Light-Cone 2024: Hadron Physics in the EIC era

25 Nov 2024, 09:00 → 29 Nov 2024, 20:00 Asia/Shanghai

Meeting Center, Institute of Modern Physics, Chinese Academy of Sciences (Huizhou, Guangdong, China)

Xingbo Zhao (Institute of Modern Physics, Chinese Academy of Sciences), Jiangshan Lan (Institute of Modern Physics), Satvir Kaur (Institute of Modern Physics), Chandan Mondal, Siqi Xu, Yair Mulian (Institute of Modern Physics), Yuxiang Zhao

Light-Cone 2024: Hadron Physics in the EIC era (LC2024) is scheduled to take place from November 25 to 29, 2024 in the Huizhou campus of the Institute of Modern Physics, Chinese Academy of Sciences.

https://english.imp.cas.cn

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Registration deadline: Nov 15, 2024

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Light-Cone 2024 continues the conference series that began in 1991, overseen by the International Light Cone Advisory Committee (ILCAC). For the information on past Light Cone conferences, please refer to the ILCAC website (http://www.ilcacinc.org/past-meetings). These conferences have been crucial for advancing our understanding of quantum field theory, quantum chromodynamics (QCD), and high-energy physics. Over time, they also evolved into a platform for exploring developments in hadron and nuclear physics, with a focus on several experimental facilities including upcoming EICs. These conferences serve as a hub where scientists come together to exchange ideas, cooperate on research, and keep pushing the boundaries of our knowledge about the smallest building blocks of the universe.

The previous conference on “Light-Cone 2023: Hadrons and Symmetries” held in Rio de Janeiro, Brazil (https://indico.in2p3.fr/event/29047) emphasized phenomenological applications where one can gain fruitful interpretations in terms of hadron-structure observables, matching the experimental efforts, carried on in many facilities around the world.

The objective of LC2024 is to design a scientific program that will inspire advancements in the leading edge of research in nuclear, hadron, and particle physics at Electron-Ion Colliders (EICs)

Light-Cone 2024 will focus on the following physics topics and theoretical/experimental tools.  

Physics Topics:     
• Physics of EIC and EicC     
• Hadron spectroscopy and reactions     
• Hadron/nuclear structure   
• Spin physics     
• Relativistic many-body physics      
• QCD phase structure

Theoretical/Experimental Tools:     
• Light-front field theory     
• AdS/CFT and holography     
• Nonperturbative QFT methods     
• Effective field theories     
• Lattice field theories      
• Quantum computing 
• Present and future facilities

We look forward to welcoming you in Huizhou in November 2024 !

logo_LC-2024.jpg

poster_LC_2024.pdf

Monday, 25 November

09:00 Opening & Photo

Plenary

1 EicC

Speaker: Jiancheng Yang

2 Exclusive reactions at Jefferson Lab and the future EIC

Deeply Virtual Compton Scattering (DVCS) is the easiest reaction that accesses the Generalized Parton Distributions (GPDs) of the nucleon. GPDs offer the exciting possibility of mapping the 3-D internal structure of protons and neutrons by providing a transverse image of the constituents as a function of their longitudinal momentum. A vigorous experimental program is currently pursued at Jefferson Lab (JLab) to study GPDs through DVCS. Recent results will be shown and discussed, in particular from experiments run after the Upgrade of JLab to 12 GeV. We will conclude by discussing the future Electron-Ion Collider (EIC), which will complete this program by studying the gluon content of nucleons and nuclei.

Speaker: Carlos Munoz Camacho

10:30 Tea Break

Plenary

3 Perspectives on TMD phenomenology at future electron-ion colliders

Transverse-Momentum dependent Distributions (TMDs) are a key tool to understand the internal partonic 3D structure of hadrons in momentum space. I will discuss some recent TMD extractions for quarks in the Nucleon, whose analyses are reaching a theoretical precision comparable to collinear Parton Distribution Functions (PDFs), and I will show the potential impact of future electron-ion colliders. On the contrary, gluon TMDs are poorly known from a phenomenological point of view. I will sketch the possible channels that can be explored at an electron-ion collider, and I will discuss a recent model calculation of all (un)polarized gluon TMDs in the Nucleon at leading twist.

Speaker: Prof. Marco Radici (INFN - Sezione di Pavia)

4 Progress on generalized parton distributions and gravitational form factors

Masses and spins of hadrons are fundamental quantities in physics; however, their origins are not understood yet and their investigations are major purposes of building electron-ion colliders in 2030's. Both of them can be investigated by generalized parton distributions (GPDs). The $t$-channel or spacelike ($s$-channel or timelike) GPDs are studied by deeply virtual Compton scattering (two-photon processes) at charged-lepton accelerator facilities ($e^+ e^-$ collider facilities) such as the JLab, CERN-AMBER, and EICs (KEKB). Here, the $s$-channel GPDs are generally called generalized distribution amplitudes (GDAs) and they could be also called timelike GPDs because they contain timelike form factors. I discuss experimental prospects mainly at the $e^+ e^-$ collider KEKB, the hadron-accelerator facility J-PARC, and the Long-Baseline Neutrino Facility (LBNF) at Fermilab. It is possible to extract the $s$-channel GPDs and gravitational form factors of hadrons by the two-photon processes $\gamma^* + \gamma \to h + \bar h$, where h is a hadron. Actually, there was the first report on the determination of the gravitational form factors and radii (mass and mechanical radii were 0.32-0.39 fm and 0.82-0.88 fm for $\pi^0$) from actual experimental measurements in Ref.[1]. At J-PARC, the GPDs will be investigated by the exclusive Drell-Yan process $\pi^- p \to \mu^+ \mu^- B$ [2], where the baryon B could be a nucleon or $\Delta$. In future, other processes could be investigated for the GPDs. For example, the $2 \to 3$ reaction processes $NN \to N \pi B$ could be used for probing the GPDs in the ERBL (Efremov-Radyushkin-Brodsky-Lepage) region. In addition, the neutrino facility Fermilab-LBNF, possibly also the nuSTORM at CERN, can be used for the GPD measurement by the single-pion production processes $\nu + N \to \ell^- + N' + \pi$ and $\bar\nu + N \to \ell^+ + N' + \pi$ [3].

References
[1] S. Kumano, Qin-Tao Song, and O. V. Teryaev, Phys. Rev. D 97, 014020 (2018).
[2] S. Kumano, M. Strikman, and K. Sudoh, Phys. Rev. D 80, 074003 (2009), T. Sawada et al., Phys. Rev. D 93, 114034 (2016); J-K. Ahn et al., Letter of Intent for J-PARC, LoI_2019-07; Wen-Chen Chang et al., J-PARC proposal under preparation.
[3] X. Chen, S. Kumano, R. Kunitomo, S. Wu, and Y.-P. Xie, arXiv:2401.11440, European Physical Journal A, in press.

Speaker: Shunzo Kumano (Japan Women's University / KEK)

5 Probing the Quark Orbital Angular Momentum at EIC and EicC

We propose to detect signals from quark orbital angular momentum (OAM) through exclusive π production in electron-(longitudinally-polarized) proton collisions. Our analysis demonstrates that the sin 2ϕ azimuthal angular correlation between the transverse momentum of the scattered electron and the recoil proton serves as a sensitive probe of quark OAM. Additionally, we present a numerical estimate of the asymmetry associated with this correlation for the kinematics accessible at EIC and EicC. This study aims to pave the way for the first experimental study of quark OAM in relation to the Jaffe-Manohar spin sum rule.

Speaker: Prof. Jian Zhou (Shandong University)

12:30 Lunch

Parallel-1

6 Light cone distribution of light meson on lattice

The light cone distribution of light mesons, encompassing both one-dimensional light cone distribution amplitudes (LCDAs) and three-dimensional transverse momentum dependent wave functions (TMDWFs), provides insight into the inner structure of hadrons. These distributions are crucial inputs for perturbative calculations in hard exclusive processes. In this talk, I will present recent advancements in the research of both LCDAs and TMDWFs on the lattice. I will particularly focus on the applications of the LaMET framework for LCDAs of pseudoscalar and vector mesons, as well as TMDWFs for pions.

Speaker: Jun Hua (South China Normal University)

7 Determining heavy meson light-cone distribution amplitudes from lattice QCD

We develop an new approach for calculating heavy quark effective theory (HQET) light-cone distribution amplitudes (LCDAs) by employing a sequential effective theory methodology. The theoretical foundation of the framework is established, elucidating how the quasi distribution amplitudes (quasi DAs) with three scales can be utilized to compute HQET LCDAs. We provide theoretical support for this approach by demonstrating the rationale behind devising a hierarchical ordering for the three involved scales, discussing the factorization at each step, clarifying the underlying reason for obtaining HQET LCDAs in the final phase, and addressing potential theoretical challenges. The lattice QCD simulation aspect is explored in detail, and the computations of quasi DAs are presented. We employ three fitting strategies to handle contributions from excited states and extract the bare matrix elements. For renormalization purposes, we utilize the state-of-the-art techniques and apply hybrid renormalization schemes at short and long distance separations. To mitigate long-distance perturbations, we perform an extrapolation in $\lambda= z\cdot P^z$ and assess the stability against various parameters. After two-step matching, our results for HQET LCDAs are found in agreement with existing model parametrizations. The potential phenomenological implications of the results are discussed, shedding light on how these findings could impact our understanding of the strong interaction dynamics, and physics beyond the standard model.

Speaker: Qi-An Zhang (Beihang University)

8 The EMC effect within the light-front Hamiltonian dynamics for few-nucleon bound systems

Speaker: Filippo Fernetti

Parallel-2

9 Holographic approach to exotic hadrons

After 60 years of quantum chromodynamics (QCD) and the quark constituent model, new experimental evidence challenges existing descriptions of hadronic states. This work introduces a holographic approach to describing exotic vector states emerging in heavy quarkonium. We propose a WKB-based approach inspired by diquark Regge trajectories to infer the structure of the holographic confining potential. The eigenvalues of this potential will characterize these heavy exotic states.

Speaker: Prof. Miguel Angel Martin Contreras (University of South China)

10 Exploring the light-cone wave functions with Dyson-Schwinger equations.

In this talk I will discuss some recent progress in the study of photon and flavor asymmetric pseudoscalar meson light front wave functions made within DSEs approach.

Speaker: Chao Shi (Nanjing University of Aeronautics and Astronautics)

11 Exploring QCD Matter: Phase Transitions, Critical Endpoints, and Rotation Effects in Pure Gluon and Multi-Flavor Models

We employ the non-perturbative gauge/gravity duality approach to study the phase structure of Quantum Chromodynamics (QCD) under finite temperature, baryon chemical potential, and rotational effects. Our models include the SU(3) pure gluon system, 2-flavor QCD, and 2+1-flavor QCD, all calibrated with the latest lattice data to analyze their thermodynamic properties and predict the location of the critical endpoint (CEP). For the 2-flavor model, we find the CEP at ($\mu_\text{CEP}$,$T_\text{CEP}$) = (219, 182) MeV. We also compute critical exponents associated with the CEP and find that they almost coincide with the critical exponents of the quantum 3D Ising model. In addition, by introducing angular velocity via a local Lorentz boost, we investigate the impact of rotation on the pure gluon and 2+1 flavor QCD systems, finding that the critical temperature and baryon chemical potential decrease as rotation increases. We construct a 3D phase diagram incorporating temperature, baryon chemical potential, and angular velocity for 2+1 QCD system, as well as a 2D phase diagram for the pure gluon system. Our findings reveal several interesting phenomena near the CEP. This study provides theoretical insights into the phase structure of QCD matter under various rotational conditions.

Speaker: Yan-Qing Zhao (HaiNan Normal University)

Parallel-3

12 Solitons in quantum field theory

In the instant-time formulation of quantum field theory, solitons correspond to states. We present a new formalism for treating these states. The formalism is much simpler and easier to use than previous formalisms, making many previously impractical problems now practical. We have used it to calculate soliton masses, spectra, form factors, and scattering amplitudes, as well as the decay rates of excited solitons. Our long-term goal is to treat the monopoles whose condensation may be responsible for confinement in QCD.

Speaker: Jarah Evslin (Institute of Modern Physics, CAS)

13 Feasibilty study about Sullivan Process on the u-channel

This work presents a systematic feasibility study on measuring backward deeply virtual Compton scattering (bDVCS) on the pion through Sullivan processes, within the framework of collinear QCD factorization. In this approach, pion-to-photon transition distribution amplitudes (TDAs) are used to describe the photonic structure of the pion. Using the TDA framework considering overlap of light-front wave functions, we aim to estimate the cross-section for DVCS processes and evaluate the prospects for future measurements at electron-ion colliders in the U.S. and China.

Speaker: Abigail Rodrigues Castro (CEA-Saclay)

14 Exploring the pion off-shell effects in the light-front

The off-shell pion electromagnetic form factors are explored
using phenomenological relativistic constituent quark models. These composite pion models feature
massive, structureless blue quark and antiquark, allowing the computation of microscopic form factors
via the Mandelstam approach. Each model relies on two parameters which are determined by closely reproducing the pion decay constant and charge radius.

The existing data on the cross-sections for the Sullivan process, $^1\text{H}(e,e',\pi^+)n$, where pion pole dominance and low off-shell virtuality permit comparison with the model results as well as
the extraction of the off-shell pion form factor.

The off-shell form factor is not directly accessible by electron scattering but can be derived from a relation
based on the Ward-Takahashi identity for the pion electromagnetic current.

We found that the adopted models reproduce the extracted off-shell form factor
$F_1(Q^2,t)$ for $t<0$ from these cross-sections with an accuracy of a few percent.

Additionally, we extracted the new form factor $g(Q^2,t)$
which is directly related with the charge radius of the
pion $g(Q^2=0, m_\pi^2) = /6$, exhibiting a variation of about 10\%
within the models used in this work.
We also identify the pion valence parton distribution function (PDF)
and transverse momentum distribution (TMD) in terms of the light-front wave function and discuss their
on-shell properties.

Speaker: João Pacheco de Melo (LFTC - Universidade Cruzeiro do Sul - UNICID)

15:30 Tea Break

Parallel-1

15 Dihadron azimuthal asymmetry and light-quark dipole moments at the Electron-Ion Collider

We propose a novel method to probe light-quark dipole moments by examining the azimuthal asymmetries between a collinear pair of hadrons in semi-inclusive deep inelastic lepton scattering off an unpolarized proton target at the Electron-Ion Collider. These asymmetries provide a means to observe transversely polarized quarks, which arise exclusively from the interference between the dipole and the Standard Model interactions, thereby depending linearly on the dipole couplings. We demonstrate that this novel approach can enhance current constraints on light-quark dipole operators by an order of magnitude, free from contamination of other new physics effects. Furthermore, it allows for a simultaneous determination of both the real and imaginary parts of the dipole couplings, offering a new avenue for investigating potential $CP$-violating effects at high energies.

Speaker: Bin Yan (IHEP)

16 Meson Structure Program at EicC

As the simplest quark-antiquark systems, pions and kaons are pseudo Nambu-Goldstone bosons closely related to the spontaneous symmetry breaking of the strong interaction. The study of their form factors and parton distribution functions is not only key to understanding their internal structures, but also tied to the mechanism of Emergent Hadron Mass, one of the mass generation mechanisms in the Standard Model, together with Higgs boson mechanism. Despite the long-standing discovery of pions and kaons, there is still a lack of understanding of their internal structure and dynamic characteristics, especially given the scarcity of experimental data due to their instability. However, the Sullivan process, taking advantage of the virtual meson cloud of a nucleon, provides a special approach to overcome this difficulty. Such an approach has been validated at HERA, DESY, JLab, and will be adopted by future EIC and EicC to collect more data in a wider kinematic range.
In this talk, I will discuss in detail how EicC can provide a unique platform for studying the structure of pions and kaons, and present their projected results. I will also emphasize the uniqueness of the EicC, and its complementarity to other facilities, such as JLab and EIC.

Speaker: ZongYang Lu (Shandong University)

17 Probing gluon 3D structure by using linearly polarized photons at EICs

As Fermi had realized 100 years ago (in 1924), the electromagnetic field inspired by fast moving charged particles can be treated as photon flux, i.e, equivalent photon approximation (EPA). The EPA photons are linearly polarized, which can be used to probe the nucleus 3D structure. We studied the azimuthal asymmetries induced by the linearly polarized photons in exclusive $\rho^0$ and $J/\psi$ production in eA collisions at EIC energies and in UPCs at heavy-ion colliders, in the framework of color glass condensate effective theory. In addition, we will briefly discuss searching for the evidence of the Coulomb correction in the Bethe-Heitler process at EICs.

Speaker: Yajin Zhou (Shandong University)

18 Illuminating Nucleon Gluon Interference via Calorimetric Asymmetry

We present an innovative approach to the linearly polarized gluons confined inside the unpolarized nucleon in lepton-nucleon scattering. Our method analyzes the correlation of energy flows at azimuthal separations $\phi$.
The interference of the spinning gluon with both positive and negative helicities translates into a $\cos(2\phi)$ asymmetry imprinted on the detector. Unlike the conventional transverse momentum dependent (TMD) probes, the $\cos(2\phi)$ asymmetry in this approach is preserved by rotational symmetry, holds to all orders, and is free of radiation contamination, thus expected to provide the exquisite signature of the nucleon linearly polarized gluons.

Speaker: Xiaolin Li (Beijing Normal University)

19 Azimuthal modulation in light-by-light scattering from ultraperipheral collisions at LHC

Elastic light-by-light (LbL) scattering, one of the most fascinating processes in the Standard Model (SM), has recently been observed in the ultraperipheral collisions (UPCs) of relativistic heavy ions in the Atlas and CMS experiments at the Large Hadron Collider (LHC). However, the measured LbL cross section exhibits noticeable tension with the SM predictions based on the collinear factorization approach. Recognizing that the incident quasi-real photons in LbL scattering are strongly linearly polarized, we re-investigate the LbL scattering at UPCs by incorporating the joint dependence of the impact parameter and transverse momenta of the incident photons. Accounting for these effects alleviates the tension between the Atlas measurements and the preceding predictions from collinear factorization. Moreover, we show that the linear polarization of incident photons generates a sizable cos 2ϕ-type azimuthal modulation, which awaits the test in future LHC and EIC/EicC experiments.

Speaker: 硕 林 (中国科学技术大学)

20 Measurement of charge-dependent directed flow in STAR Beam Energy Scan (BES-II) Au+Au and U+U Collisions

The presence of ultra-strong electromagnetic (EM) fields can give rise to various important phenomena in heavy ion collisions (HIC). During the early stages of HI collisions an ultra-strong EM field ($B \approx 10^{18}$ Gauss) is expected to be generated, which can have profound implications for QCD phase transitions as well as chiral symmetry restoration. The charge-dependent directed flow ($v_1$) serves as a potential tool for detecting EM field effects and QCD medium properties [1].

In this talk, we will present measurements of directed flow ($v_1$) for identified particles ($\pi^\pm$, $K^\pm$, and $p/\bar{p}$) and their charge dependence, conducted by the STAR experiment in Au+Au collisions at $\sqrt{s_{NN}} = 7.7$–$200$ GeV including the RHIC Beam Energy Scan, as well as in isobar (Ru+Ru and Zr+Zr) collisions at $\sqrt{s_{NN}} = 200$ GeV and U+U collisions at $\sqrt{s_{NN}} = 193$ GeV. The $v_1$ values will be reported as functions of rapidity, transverse momentum and collision centrality. Comparisons of the slope ($dv_1/dy$) and the charge-dependent difference, $\Delta(dv_1/dy)$, across different collision systems and energies, including U+U, Au+Au, and isobar (Ru+Ru and Zr+Zr) collisions, aim to provide insights into electromagnetic field effects and transport coefficients of the QCD medium, such as electrical conductivity.

[1] STAR Collaboration, Phys. Rev. X 14, 011028

Speaker: Muhammad Farhan Taseer (for the STAR Collaboration) (Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China)

Parallel-2

21 Holographic renormalized Entanglement and entropic c-function

We compute holographic entanglement entropy (EE) and the renormalized EE in AdS solitons with gauge potential for various dimensions. The renormalized EE is a cutoff-independent universal component of EE. Via Kaluza-Klein compactification of S1 and considering the low-energy regime, we deduce the (d−1)-dimensional renormalized EE from the odd-dimensional counterpart. This corresponds to the shrinking circle of AdS solitons, probed at large l. The minimal surface transitions from disk to cylinder dominance as l increases. The quantum phase transition occurs at a critical subregion size, with renormalized EE showing non-monotonic behavior around this size. Across dimensions, massive modes decouple at lower energy, while degrees of freedom with Wilson lines contribute at smaller energy scales.

Speaker: Mitsutoshi Fujita (University of South China)

22 Simulating Parton Fragmentation on Quantum Computers

Parton fragmentation functions (FFs) are indispensable for understanding processes of hadron production ubiquitously existing in high-energy collisions, but their first principle determination has never been realized due to the insurmountable difficulties in encoding their operator definition using traditional lattice methodology. We propose a framework that makes a first step for evaluating FFs utilizing quantum computing methodology. The key element is to construct a semi-inclusive hadron operator for filtering out hadrons of desired types in a collection of particles encoded in the quantum state. We illustrate the framework by elaborating on the Nambu-Jona-Lasinio model with numeral simulations. Remarkably, We show that the semi-inclusive hadron operator can be constructed efficiently with a variational quantum algorithm. Moreover, we develop error mitigation techniques tailed for accurately calculating the FFs in the presence of quantum noises. Our work opens a new avenue for investigating QCD hadronization on near-term quantum computers.

Speaker: Tianyin Li (South China Normal University)

23 Bell-CH Inequalities and Quantum Nonlocality in Spin-Correlated Decays

Quantum nonlocality, a fundamental feature of quantum mechanics, is frequently associated with the experimental violation of Bell-Clauser-Horne (Bell-CH) inequalities. We present a set of novel methods for the rearrangement and linear inequalities to derive a broad class of Bell-CH inequalities, which can be violated by particular quantum-entangled states. The rapid advancements in Quantum Information Science (QIS) have opened new avenues for probing fundamental aspects of physics. Central to distinguishing quantum information from classical information, quantum nonlocality has been extensively investigated through the violation of Bell-CH inequalities in particle decay processes. Nonetheless, a comprehensive framework grounded in quantum information theory for particle interactions remains elusive. To bridge this gap, we propose a generalized quantum measurement framework for spin-1/2 hyperon decay processes, aligning this approach with established theoretical models and applying it to the joint decay of correlated $\Lambda \overline{\Lambda}$ pairs. Utilizing quantum simulations, we demonstrate the violation of Bell-CH inequalities in hyperon decays. This generalized measurement framework is versatile and can be extended to a range of high-energy processes, including the decays of vector mesons, $J/\psi$ and $\psi(2S) \rightarrow \Lambda \overline{\Lambda}$, within the Beijing Spectrometer III (BESIII) experiment at the Beijing Electron Positron Collider (BEPC).

Speaker: Dr Yangguang Yang (Institute of Modern Physics, Chinese Academy of Sciences)

24 Next-to-leading order photon+jet production

Using the CGC effective theory together with the hybrid factorisation in light-cone formalism, we study forward photon+jet production in proton-nucleus collisions beyond leading order. We first compute the "real" next-to-leading order (NLO) corrections, i.e. the radiative corrections associated with a three-parton final state, out of which only two are being measured. Then we move to the "virtual" NLO corrections to di-jet production, in which a gluon loop is included as a part of the amplitude, before or after the measurement. Each of these loop diagrams diverges, and we explain our treatment in order to obtain finite expression for the cross section. We explicitly work out the interesting limits where the unmeasured gluon is either a soft, or the product of a collinear splitting. We find the expected results in both limits: the B-JIMWLK evolution of the leading-order dijet cross-section in the first case (soft gluon) and, respectively, the DGLAP evolution of the initial and final states in the second case (collinear splitting).

Speaker: Yair Mulian (Institute of Modern Physics)

25 Structure Functions from the BK evolution

We fit the structure function $F_2$ data from HERA using the Balitsky-Kovchegov (BK) equation. The non-linear equation for the unintegrated gluon density is solved, also incorporating resummations due to the DGLAP evolution and kinematical constraints. Parallel computation on GPUs is employed to handle the intensive calculations, achieving a good fit to the structure function with $\chi^2 \sim 1.5$. Notably, we extend the range of integration in the BK equation to a minimum $k^2 = 10^{-3} \, \text{GeV}^2$, successfully capturing a part of the soft contribution that was previously modeled with collinear approximation in earlier approaches.

Speaker: Wanchen Li (Fudan University)

26 Nucleon relativistic weak-neutral axial-vector four-current distributions

Relativistic full weak-neutral axial-vector four-current distributions inside a general spin-$\frac{1}{2}$ system are systematically studied for the first time. We show in particular that the slope of the axial form factor $G_A(Q^2)$ in the forward limit -- conventionally denoted as $R^2_A$ in the literature -- does not represent the three-dimensional mean-square axial radius in the Breit frame, but corresponds instead to a contribution to the mean-square spin radius. We derive explicit expressions for the latter in different frames and find in general additional contributions that depend on both the nucleon mass and the forward values of the axial-vector form factors $G_A(0)$ and $G_P(0)$. This provides an additional key motivation for on-going lattice QCD calculations and future experimental measurements of the induced pseudoscalar form factor $G_P(Q^2)$.

Speaker: Yi Chen (University of Science and Technology of China, China)

Parallel-3

27 Nucleon tomography in the threshold limit

We apply the joint threshold and transverse momentum dependent (TMD)
factorization theorem to introduce new threshold-TMD distribution functions, including threshold-TMD parton distribution functions (PDFs) and fragmentation functions (FFs). We apply Soft-Collinear Effective Theory and renormalization group methods to perform QCD evolution for both threshold-TMD PDFs and FFs. We show the universality of threshold-TMD functions among three standard processes, i.e., the Drell-Yan production in pp collisions, semi-inclusive deep-inelastic scattering, and back-to-back two hadron production in e+e- collisions.

Speaker: Dingyu Shao (Fudan University)

28 Precision three-dimensional imaging of nuclei using recoil-free jets

In this study, we explore the azimuthal angle decorrelation of lepton-jet pairs in e-p and e-A collisions as a means for precision measurements of the three-dimensional structure of bound and free nucleons. Utilizing soft-collinear effective theory, we perform the first-ever resummation of this process in e-p collisions at NNLL accuracy using a recoil-free jet axis. Our results are validated against Pythia simulations. In e-A collisions, we address the complex interplay between three characteristic length scales: the medium length $L$, the mean free path of the energetic parton in the medium $\lambda$, and the hadronization length $L_h$. We demonstrate that in the thin-dilute limit, where $L \ll L_h$ and $L \sim \lambda$, this process can serve as a robust probe of the three-dimensional structure for bound nucleons. We conclude by offering predictions for future experiments at the Electron-Ion Collider within this limit.

Speaker: 申 方 (复旦大学)

29 Transverse-momentum-dependent wave functions and soft functions at one-loop in large momentum effective theory

In large-momentum effective theory (LaMET), the transverse-momentum-dependent (TMD) light-front wave functions and soft functions can be extracted from the simulation of a four-quark form factor and equal-time correlation functions. In this work, using expansion by regions we provide a one-loop proof of TMD factorization of the form factor. For the one-loop validation, we also present a detailed calculation of ${\cal O}(\alpha_s)$ perturbative corrections to these quantities, in which we adopt a modern technique for the calculation of TMD form factor based the integration by part and differential equation. The one-loop hard functions are then extracted. Using lattice data from Lattice Parton Collaboration on quasi-TMDWFs, we estimate the effects from the one-loop matching kernel and find that the perturbative corrections depend on the operator to define the form factor, but are less sensitive to the transverse separation. These results will be helpful to precisely extract the soft functions and TMD wave functions from the first-principle in future.

Speaker: 志福 邓 (香港中文大学 深圳)

30 Global analysis of Sivers and Collins asymmetries within TMD factorization

We will present a global analysis of Sivers function, transversity distribution functions and Collins fragmentation functions within TMD factorization. This analysis encompasses the latest data sets from semi-inclusive deep inelastic scattering, Drell-Yan, and $W^{\pm}/Z$-boson production as recently reported by the COMPASS and STAR Collaborations. Upon integrating this new data into our fitting, the accuracy of the $d$ and $\bar{d}$ quark extraction for both transversity and Sivers distribution is notably improved, as well as the tensor charge. Alongside this enhancement, we observed a positive transversity distribution for the $\bar{d}$ quark for the first time .

Speaker: Hongxin Dong (NNU)

31 A new contribution to Single Transverse Spin Asymmetry in forward pp and pA collisions

Nuclear dependence of Single Transverse Spin Asymmetry (STSA) in $p^↑ p$ and $p^↑ A$ collisions is still a standing mystery. Recent results by PHENIX ($A^{-1/3}$) [1] and STAR ($A^0$) [2] collaborations posses strikingly different nuclear scaling which suggest that the dominant underlying mechanism for STSA may vary with the kinematics of the collision. In the forward regime, where the gluon saturation effects become important, and where the collisions are described in the so-called hybrid formalism [3], two contributions to STSA in $p^↑ p$ and $p^↑ A$ collisions have been found [4,5]. In [5], the phase required for STSA comes from the imaginary part of twist-3 fragmentation function (FF) with the polarized projectile described with Transversity parton distribution function and the unpolarized target with real part of Dipole distribution, Pomeron. We have found a new contribution to STSA [Benić, Vivoda in preparation] which comes from the combination of real part of genuine twist-3 FF and the imaginary part of dipole distribution, Odderon. The Odderon mechanism to STSA is known to generate significant nuclear dependance [6] and we expect that this approach could shine a new light at RHIC data [1,2]. Also, this contribution will give us some insight into the real part of the twist-3 FF which has not yet been constrained by global fits [7]. In this talk I will first provide a formula for polarized cross section and then discuss our numerical results for STSA [Benić, Vivoda in preparation].

References:
[1] C. Aidala et. al. (PHENIX Collaboration), Phys. Rev. Lett. 123, 122001 (2019).
[2] J. Adam et. al. (STAR Collaboration), Phys. Rev. D 103, 072005 (2021).
[3] A. Schafer and J. Zhou, Phys. Rev. D 90, 034016 (2014), 1404.5809.
[4] Y. Hatta, B.-W. Xiao, S. Yoshida and F. Yuan, Phys. Rev. D 94, 054013 (2016).
[5] Y. Hatta, B.-W. Xiao, S. Yoshida and F. Yuan, Phys. Rev. D 95, 014008 (2017).
[6] Y. V. Kovchegov and M. D. Sievert, Phys. Rev. D 86, 034028 (2012), [Erratum: Phys.Rev.D 86, 079906 (2012)].
[7] L. Gamberg et al. (Jefferson Lab Angular Momentum (JAM) Collaboration), Phys. Rev. D 106, 034014 (2022).

Speakers: Eric Andreas Vivoda (Department of Physics, Faculty of Science, University of Zagreb), Sanjin Benic (University of Zagreb)

32 Generalized parton distributions of the proton from a light-front QCD Hamiltonian

We solve the nucleon's wave functions as eigenstates of the light-front quantum chromodynamics (QCD) Hamiltonian for the first time, using a fully relativistic and nonperturbative approach based on light-front quantization, without an explicit confining potential. These eigenstates are determined for the three-quark, three-quark-gluon, and three-quark-quark-antiquark Fock sectors, making them suitable for low-resolution probes. From this, we calculate generalized parton distributions (GPDs) at nonzero skewness in both the DGLAP and ERBL regions. Our results show qualitative agreement with other theoretical approaches. We further convolute our GPDs with the tree-level hard function, demonstrating the feasibility of calculating Compton form factors within tree-level factorization.

Speaker: 一平 刘 (近代物理所)

18:10 Buffet

Tuesday, 26 November

Plenary

33 Basis Light-Front Quantization: recent results and future prospects

Speaker: James Vary

34 Gluon mass and small $x$ in QCD Hamiltonian for hadronic constituents

The canonical Hamiltonian of QCD in the front form involves severe small-$x$ divergences that impede access to the logarithmically scale-dependent Hamiltonians for quarks and gluons. We propose a method for circumventing these divergences, thus opening a pathway for the systematic computation of the Hamiltonians using the renormalization group procedure for effective particles (RGPEP). Our approach involves a gluon mass parameter and an auxiliary scalar octet field whose quanta correspond to the longitudinal gluons. The auxiliary field drops out of the dynamics in the limit of the gluon mass parameter going to zero. We first explain how the severe small-x divergences can cancel out in the quark and gluon scattering amplitudes in the femtouniverse despite our introduction of mass for gluons. Then we discuss the cancelation in the renormalized bound-state dynamics, using the RGPEP. Hence, the perturbative and bound-state features of the theory are approached in the same formulation, instead of matching complementary formulations in the different regimes.

Speaker: Stanislaw Glazek (University of Warsaw)

35 Nucleon charge and gravitational radii

Speaker: Fengkun Guo

10:30 Tea Break

Plenary

36 Light-Front Physics from Continuum Schwinger Function Methods

Speaker: Craig Roberts

37 PDF Global Analysis with Lattice-QCD Input

Speaker: Tiejiun Hou

38 Lambda polarization in deep inelastic scattering

Speaker: Tianbo Liu

12:30 Lunch

Parallel-1

39 Gluon Distributions in the proton

Though the quark distributions are are studied in different models, the gluon distributions inside the proton are not studied extensively. To understand the three dimensional structure of proton and the spin and angular momentum contributions of different partons, it is important to evaluate the gluon GPDs and TMDs. We will define a simple spectator model to study the gluon distributions in the proton. Results for orbital angular momentum, spin-orbit correlations will also be discussed.

Speaker: Prof. Dipankar Chakrabarti (Indian Institute of Technology Kanpur)

40 Glueballs in QCD sum rules

Glueballs are colorless bound states of gluons as they have self-couplings. The existence of glueballs are very distinctive predictions of QCD. In this talk, I will briefly review recent experimental and theoretical progresses on the researches of glueballs. Especially, I will introduce the latest QCD sum rule calculations of the mass spectroscopy for the two-gluon and three-gluon glueballs.

Speaker: Wei Chen (Sun Yat-Sen University)

41 Angular momentum distribution for a quark dressed with a gluon

We investigate different decompositions of angular momentum in QCD for a relativistic spin 1/2 composite state, specifically a quark dressed with a gluon. We employ light-front Hamiltonian perturbation theory developed in the light-front gauge and utilize a two-component framework that eliminates constrained degrees of freedom. Our investigation extends to various decompositions of angular momentum, examining two-dimensional densities in the light-front formalism, and considers the impact of potential terms. We contrast these decompositions with other literature findings and explore the gravitational form factor associated with the antisymmetric part of the energy-momentum tensor. Additionally, we verify angular momentum sum rules to ensure consistency

Speaker: Mr Sudeep Saha (Indian Institute of Technology Bombay, India)

Parallel-2

42 Exclusive production and polarization of $\chi_c$'s as Odderon signatures at the EIC and EIcC

Exclusive $\chi_c$ production is sensitive to the C-odd colorless tri-gluon correlation in the $t$-channel - the long sought Odderon. While a non-perturbative C-odd compound has been recently discovered through elastic $pp$ collisions [1], however, Odderon escaped the direct detections at HERA. At the EIC and the EIcC, the high luminosity can counteract the feeble Odderon amplitude. Using the high energy light-cone approach we compute the amplitude and the cross section for $\chi_{c0}$, $\chi_{c1}$ and $\chi_{c2}$ production. We find an excess above the Primakoff background as well as the characteristically slow falling t-distribution, predicting about a dozen events per month should be seen at the EIC. In the low-$t$ region a contribution from the spin dependent Odderon is revealed that is closely related to the gluon Sivers function [3]: one of the main targets at the future EIC and EIcC. Focusing on axial vector $\chi_{c1}$, where the Coulomb tail (~1/|t|) of the Primakoff process is screened (Landau-Yang theorem), the spin dependent Odderon can be directly probed in unpolarized $\gamma+p$ collisions. The two contributions (spin dependent Odderon and photon) can be disentangled by accessing the $\chi_{c1}$ polarization via the angular distribution of its decay products revealing another potential signature for the Odderon at the EIC.

Speaker: Sanjin Benic (University of Zagreb)

43 Diffractive processes at next-to-leading order in the color-glass condensate

The gluon density in nucleons has been observed to increase rapidly with energy, which would eventually violate unitarity. At high energies, however, nonlinear effects in QCD start to become important, slowing down the evolution of the gluon density and hence giving rise to gluon saturation. To study this saturation region of QCD one possibility is to look at diffractive processes which are approximately proportional to the gluon density squared and thus especially sensitive to saturation effects. It is then important to have a precise theoretical understanding of diffractive processes which includes calculating these to higher orders in perturbation theory.

In this talk, I will explain how light-cone perturbation theory can be used for a systematic treatment of higher-order corrections in the color-glass condensate framework. The talk will focus specifically on diffractive processes such as inclusive diffraction and exclusive vector meson production. I will discuss the cancellation of divergences at next-to-leading order, and show numerical comparisons to the experimental data from HERA and the LHC.

Speaker: Jani Penttala (UCLA)

44 How well does nonrelativistic QCD factorization work for inclusive quarkonium production at next-to-leading order?

Speaker: Xiangpeng Wang

Parallel-3

45 Renormalized Hamiltonian of QCD

The most challenging aspect of Quantum Chromodynamics (QCD) is perhaps the complexity of calculations required to obtain precise results. For example, ab initio Lattice QCD calculations demand expensive computations on large supercomputers. Yet, existing machines are still not sufficiently powerful to fully address many interesting problems such as structure functions of hadrons, or hadronization processes. In fact, conventional computers may never be powerful enough to simulate time evolution of quark matter. On the other hand, fault-tolerant quantum computers may offer resources required to perform those calculations in the future. Front form of Hamiltonian dynamics is one of the natural high-energy-physics frameworks one can hope to employ on a quantum computer. In order to successfully simulate QCD on a quantum computer one has to address the problem of renormalization. We report on the progress of calculation of the renormalized Hamiltonian of QCD using renormalization group procedure for effective particles. Using canonical Hamiltonian of QCD as a starting point we derive an effective (renormalized) Hamiltonian up to second order in the coupling constant. Our Hamiltonian is free from ultraviolet divergences and can be diagonalized without the need to adjust the parameters as a function of the basis size (accuracy of the calculation), as opposed to typical renormalization schemes. This allows for separation between the renormalization process and the diagonalization process. Therefore, the challenges and uncertainties inherent to the two processes are also separated and the resulting Hamiltonian can be used in conjunction with any diagonalization method (classical or quantum). Additionally, the problem of complicated structure of effective interactions is overcome with the discovery of a simplified form of the renormalized Hamiltonian. We also comment on some known challenges that still need to be addressed.

Speaker: Kamil Serafin (Tufts University)

46 Effective quarks and gluons forming hadrons in the Fock space

Speaker: Maria Gomez Rocha

47 In-medium dressed quark evolution in a light-front Hamiltonian approach

Using a non-perturbative light-front Hamiltonian approach, we investigate the scattering and gluon emission of dressed quark states inside a SU(3) colored background field. We consider the scenario in deep inelastic scattering and in heavy ion collisions, where the quark originates from far outside the background field and is described by the light-front wavefunction of the QCD eigenstate in the |q>+|qg> Fock space. We perform numerical simulations of the real-time quantum state evolution of an initially dressed quark state. We then extract the jet momentum distribution, the cross section, and the gluon emission rate. This investigation provides a novel systematic description of in-medium jet evolution using a non-perturbative formalism.

Speaker: Meijian Li (IGFAE)

15:30 Tea Break

Parallel-1

48 The D-term of the proton with basis light-front quantization

We compute the gravitational form factors (GFFs) and study their applications for the description of the mechanical properties such as the pressure, shear force distributions, and the mechanical radius of the proton from its light-front wave functions (LFWFs) based on basis light-front quantization (BLFQ). We find acceptable agreement between our BLFQ computations and the lattice QCD for the GFFs. Our $D$-term form factor also agrees well with the extracted data from the deeply virtual Compton scattering experiments at Jefferson Lab, and the results of different phenomenological models. The distributions of pressures and shear forces are similar to those from different models.

Speaker: Sreeraj Nair (The Institute of Modern Physics (IMP) of the Chinese Academy of Sciences)

49 Gravitational form factors of charmonium on the light front

We investigate the internal stress of charmonium using the recently derived light-front wave function representation. We employ three “good components” of the energy-momentum tensor, $T^{++}$, $T^{+-}$, and $T^{12}$, to extract the gravitational form factors. The obtained form factors satisfy the known constraints and are used to derive the physical distributions of the system. We discover tantalizing evidence of a tachyonic core within $\eta_c$. Additionally, we find an attractive core within $\chi_{c0}$, contradicting the speculation based on mechanical stability that a stable system must have a repulsive core.

Speaker: Tianyang Hu (Institute of Modern Physics, CAS)

50 Gravitational form factors on the light-front

We investigate the gravitational form factors of a strongly coupled scalar theory in the light-front Hamiltonian approach. The theory can be used to mimic the interaction between the nucleon and the pion. We renormalize the energy-momentum tensor with a Fock sector-dependent scheme. We futher analyze the hadron matrix elements of the energy-momentum tensor and identify three “good currents” to be used to extract the physical form factors. We show that these currents are free of spurious contributions and are consistent with the covariant perturbation theory in the perturbative limit. We present the gravitational form factors of the nucleon within a Fock space up to three particles (one nucleon plus two pions). The extracted form factors obey known sum rules, including the von Laue condition. Based on the investigation of the scalar theory, we propose a systematic non-perturbative wave function representation of the gravitational form factors, which is then applied to various systems, e.g. the pion and charmonium.

Speaker: Xianghui Cao (University of Science and Technology of China)

51 Basis Light-front Quantization Approach to $\Lambda_b$ and $\Sigma_b$ Baryons

Within Basis light-front Quantization framework, we obtain the masses comparable to experiment and the light-front wave functions of $\Lambda_b$ and its isospin triplet baryons $\Sigma_b^+$, $\Sigma_b^0$ and $\Sigma_b^-$. Our prediction of their electromagnetic properties is in agreement with other theoretical calculations. Meanwhile their parton distribution functions (PDFs) are obtained with the gluon and the sea quark PDFs generated dynamically from the QCD evolution of the valence ones.

Speaker: Lingdi Meng (Institute of Modern Physics, Chinese Academy of Sciences)

52 Double parton distributions of the proton from basis light-front quantization

Within the basis light-front quantization framework, we systematically investigate the unpolarized and longitudinally polarized double parton distributions (DPDs) of quarks inside the proton. We utilize the light-front wave functions of the proton derived in the valence sector from a Hamiltonian quantized on the light-front. Our current analysis yields significant correlations of the quarks' longitudinal momenta with their transverse separation. We also demonstrate that our calculations do not support the commonly used $x-\vec{k}_\perp$ factorization of the DPDs in $x$ and $k_\perp$.

Speaker: Tiancai Peng (Lanzhou university)

53 Flavor asymmetry from the non-perturbative nucleon sea

We demonstrate, in the context of a scalar version of the chiral effective field theory, that the multi-sea quark contribution to the nucleon is significant and highly non-trivial in sharp contrast to the prediction of perturbation theory. The non-perturbative calculation is performed in the Fock sector dependent renormalization scheme on the light front, in which the non-perturbative renormalization is incorporated. The calculation suggests that a fully non-perturbative calculation of the chiral EFT is needed to obtain a robust result to be compared with the recent experimental measurement of flavor asymmetry in the proton.

Speaker: Yihan Duan (University of Science and Technology of China)

Parallel-2

54 Quark helicity PDFs of proton from lattice QCD

In this talk I will present the results of lattice calculation of the quark helicity PDFs of proton.

Speaker: Hai-Tao Shu (CCNU)

55 Total Gluon Helicity from Lattice without Effective Theory Matching

We propose two approaches for extracting the total gluon helicity contribution to proton spin from lattice QCD, one from local operator matrix elements in a fixed gauge accessible on lattice with feasible renormalization, and the other from gauge-invariant nonlocal gluon correlators. Neither of these approaches requires a matching procedure when converted to the MS scheme. Our proposal resolves a long-standing inconsistency in the literature regarding lattice calculations of the total gluon helicity, and has the potential to greatly facilitate these calculations.

Speaker: Zhuoyi Pang (The Chinese University of HongKong, ShenZhen)

56 ρ and ϕ vector meson spectroscopy and their diffractive production using holographic light-front QCD

We determine the mass spectroscopy and diffractive cross-section of ρ and ϕ vector meson by solving the holographic light-front Schrodinger equation along with the ’t Hooft equation of (1+1)-dimensional QCD in the large Nc limit. In order to obtained the diffractive cross-sections, we utilized the holographic LFWFs in conjunction with the color glass condensate dipole cross-section. Our spectroscopic and diffractive cross sections results are consistent with the available experimental data. Additionally, we also showed that the resulting LFWFs for the ρ and ϕ meson can effectively describe various properties, including its decay constant, distribution amplitudes, electromagnetic form factors, charge radius, magnetic and quadrupole moments.

Speaker: Bheemsehan Gurjar (IIT Kanpur)

57 The semileptonic form factors of the open-charm mesons in $N_f=4$ holographic QCD

Semileptonic decays involve the transition of a heavy meson (such as B or D) to a lighter meson via the exchange of a W boson. Understanding the form factors governing these transitions is essential for precision measurements of CKM matrix elements and testing the Standard Model. The form factors are manifestations of nonperturbative QCD processes, and various phenomenological models have been used to obtain some information on them.

In this talk, we present the study of the semileptonic form factors of $D_{(s)}$ meson from a modified soft-wall 4-flavor holographic model. We investigate the semileptonic decay processes $D^{+} \to (\pi, K, \eta) l^{+} \nu_{l}$ and $D_{s}^{+} \to ( K, \eta) l^{+} \nu_{l}$, associated with the vector meson exchange, as well as $D_{(s)}^{+} \to K^{} l^{+} \nu_{l}$, associated with the vector and axial vector meson exchange. The form factors $f_{+}(q^{2})$ for $D \to\pi$ and $D_{(s)}\to K$ decays agree excellently with experimental and lattice data, outperforming other theoretical approaches. The $f_{+}(q^{2})$ form factor for $D^{+} \to \eta $ is compatible with experimental data, while a slight discrepancy is observed for $D_{s}^{+} \to \eta $ at large $q^{2}$. Additionally, we predict the vector form factors $V(q^{2})$ and $A_{1}(q^{2})$ for $D \to K^{}$ and $D_{s} \to K^{}$ decays, respectively. The results agree well with other approaches and lattice data at maximum recoil ($q^{2}=0$).

Speaker: Mr Hiwa Ahmed (University of Chinese Academy of Scineces)

58 Covariant analysis of electromagnetic current on the light cone: exposition with scalar Yukawa theory

We present the first systematic investigation of the Lorentz covariance of the charge form factor for a strongly coupled scalar theory in (3+1)-dimensions. Our results are based on the non-perturbative solution of the scalar Yukawa theory with a Fock sector expansion including up to thee-particles (one mock nucleon plus two mock pions or two mock nucleons plus one mock anti-nucleon). The light-front Hamiltonian is constructed and renormalized using a Fock sector dependent scheme. The derived eigenvalue equation is then solved non-perturbatively to obtain the wave functions, which are then used to compute the current matrix element.We then perform a covariant analysis of the current matrix element taking into account possible violation of the Poincare symmetry due to the Fock sector truncation. The physical form factor depends on two boot invariants $\zeta$,$\Delta_\perp^2$, instead of the single Lorentz invariant $Q\\^2$. Instead of adopting the conventional Drell-Yan frame $\zeta$ = 0, we evaluate the form factor in general frames, and use the frame dependence to quantitatively gauge the loss of the Lorentz covariance. Our numerical result shows that as more Fock sectors are included, the frame dependence reduces dramatically. In particular, the anti-nucleon degree of freedom plays an important role in the reduction of the frame dependence, even though it only takes a small portion within the state vector. We also nd that there is no zero-mode contribution to the current for the scalar Yukawa theory.

Speaker: Wenyu Zhang (University of Science and Technology of China)

59 Solution of Bethe--Salpeter equation in Minkowski space with Nakanishi integral representation

We propose a method to solve for the structure of relativistic 2-body bound states from Bethe--Salpeter equations (BSEs) in Minkowski space. Particularly after introducing both the Källén--Lehmann spectral representation of dressed propagators and the Nakanishi integral representation of the Bethe--Salpeter amplitudes, the BSE for scalar bound states of scalar constituents is converted into integral equations of corresponding spectral functions. Analytical kernel functions for integrations in such equations are deduced. Numerical solutions of the BSE in Minkowski space in terms of the Nakanishi spectral functions are subsequently obtained in the massive variant of the Wick--Cutkosky model. We validate out results with those applying numerical kernels for the BSE in Minkowski space.

Speaker: Shaoyang Jia (Argonne National Laboratory)

Parallel-3

60 Kinematic power corrections to DVCS to twist-six accuracy

In this talk, I will present our calculation of kinematic power corrections $t/Q^2$ and $m^2/Q^2$ to the amplitude of deeply-virtual Compton scattering to the twist-six accuracy on a nucleon target.

Phenomenologically, this result reduces an important source of uncertainties in the QCD predictions for intermediate momentum transfers $Q^2 \sim 1 - 10 ~{\rm GeV}^2$, accessible in the existing and planned EIC experiments. In particular, we find the higher kinematic power–corrections are significant and must be considered in the data analysis.

Our calculation is carried out using techniques from conformal theory and the corresponding results are applicable to other exclusive processes involving light-ray operators.

Speaker: Yao Ji (The Chinese University of Hong Kong, Shenzhen)

61 Non-diagonal DVCS $\gamma^* \pi \to \gamma \pi \pi$ and study of meson resonances with transition GPDs

The non-diagonal hard exclusive reactions admitting a description in terms of generalized parton distributions (GPDs) with transition $N\to\Delta, N^*$ provide insight into the internal dynamics of hadron excitations. A unified description of these reactions in the complete resonance region can be performed by introducing the concept of $N \to N \pi$ transition GPDs.
In this study, we investigate a toy model of non-diagonal hard exclusive reaction involving spinless hadrons, the deeply virtual Compton scattering (DVCS) process $\gamma^* \pi \to \gamma \pi \pi$, within the framework of $\pi\to\pi\pi$ GPD. We analyze this reaction in the vicinity of intermediate resonance states, in particular, $\rho(770)$, using the partial-wave expansion and dispersive techniques.
We calculate the pion decay angular distributions of the $e^-\pi^+ \to e^- \gamma \rho^+ \to e^- \gamma \pi^+ \pi^0$ cross section, incorporating both the Bethe-Heitler and DVCS contributions. The shape of these angular distributions turns out to be sensitive to the polarization states of produced $\rho(770)$ resonance. We also construct dispersive approach based on the Omnés representation to build a phenomenological model for the $\pi\to\pi\pi$ transition GPDs. Furthermore, the application of the Froissart-Gribov projection technique to the unpolarized $\pi\to\pi\pi$ Compton form factor is examined, enabling the exploration of hadron excitation induced by a cross channel local probe with arbitrary spin.

Speaker: Sangyeong Son (Kyungpook National University)

62 Mass spectra of strange double charm pentaquarks with strangeness S=-1

The observation of the $T_{c\bar{s}}(2900)$ indicates the potential existence of strange double charm pentaquarks based on the heavy antidiquark symmetry. We systematically study
the mass spectra of strange double charm pentaquarks with strangeness $S=-1$ in both molecular and compact structures for quantum numbers $J^{P}=1/2^{-}$, $3/2^{-}$, $5/2^{-}$. By constructing the interpolating currents, the mass spectra can be extracted from the two-point correlation functions in the framework of QCD sum rule method. In the molecular picture, we
find that the $\Xi_c^{'+}D^{\ast +}$, $\Xi_{c}^{\ast +}D^{\ast +}$, $\Xi_{cc}^{\ast ++}\bar{K}^{\ast 0}$ and $\Omega_{cc}^{\ast +}\rho^{+}$ may form molecular strange double charm pentaquarks. In both pictures, the masses of the $J^P=1/2^-, 3/2^-$ pentaquarks locate within the $4.2-4.6~\mathrm{GeV}$ and $4.2-4.5~\mathrm{GeV}$ regions, respectively. As all of them are above the thresholds of their strong decay channels, they behave as a broad state, making them challenging to be detected in experiment. On the contrary,
the strange double charm pentaquark with $J^P=5/2^-$ lies below its strong decay channel, which may be a very narrow state and easy to be identified in experiment. The best observed channel is its semi-leptonic decay to double charm baryon. As the result, we strongly suggest experiments to search for $J^P=5/2^-$ strange double charm pentaquarks as a first try.

Speaker: Dr Zi-Yan Yang

63 Deconfinement in SU(N) gauge theory with a massive adjoint fermion

The $SU(N)$ Yang-Mills theory compactified on $\mathbb{R}^3 \times \mathbb{S}^1_L$ with small $L$ has many merits, for example the long range effective theory is weakly coupled and adopts rich topological structures, making it semi-classically solvable.
Due to the $SU(N) \to U(1)^{N-1}$ symmetry breaking by gauge holonomy, the low-energy effective theory can be described in terms of unbroken $U(1)$ photons and gauge holonomy.
With the addition of $N_f$ adjoint light fermions, the center symmetry breaking phase transition can be studied using the twisted partition function, i.e., fermions with periodic boundary conditions, which preserve the supersymmetry in the massless case.
In this paper, we show that in the large-$N$ abelian limit with $N_f=1$ and an $N$-independent W-boson mass, the long-range $3$d effective theory can be regarded as a bosonic field theory in $4$d with an emergent spatial dimension. The emergent dimension is flat in the confining phase, but conformally flat in the center-symmetry broken phase with a $\mathbb{Z}_2$ reflection symmetry. The center symmetry breaking phase transition itself is due to the competition between instanton-monopoles, magnetic and neutral bions controlled by the fermion mass, whose critical value at the transition point is given analytically in the large $N$ limit.

Speaker: Baiyang Zhang (河南大学)

64 Application of Pionless Effective Field Theory in 3-hadron system.

Numerous low-lying excited hadrons can only decay into final states containing one or more photons, making them challenging to detect in experiments conducted at the Large Hadron Collider. Examples of such particles include the bottom partners of the $D^∗_ {s0}(2317)$ and $D_{s1}(2460)$, whose masses have been accurately predicted through heavy quark flavor symmetry and lattice calculations. We propose to measure the masses of such particles indirectly through quantum effects. Specifically, we aim to detect the threshold of a hadron and a companion hadron with attractive interactions using the threshold cusp effect. By subtracting the mass of the companion hadron from the threshold, we can determine the mass of the target hadron. We suggest detecting the thresholds of $B^{∗}_{s0}\bar{B}_s$ and $B_{s1} \bar{B}_s$ in the $Υϕ$ energy distribution. Furthermore, we demonstrate that the masses of $D^∗_{s0}(2317)$ and $D_{s1}(2460)$ can be extracted from the $J/ψϕ$ distribution measured by the LHCb Collaboration.

Speaker: Hailong Fu (ITP)

65 Transport coefficients of dense nucleon matter at low temperature

The transport properties of dense nucleon matter at low temperatures are important but have rarely been studied in nuclear physics and astrophysics. In this work, we present a primary study of both bulk and shear viscosities of dense nucleon matter within the framework of the Boltzmann equation. To describe the static properties of nucleon matter, we apply the Walecka model in the mean-field approximation, where we also estimate the relaxation time. Our results indicate that, at linear order in scattering, the relaxation time is proportional to the quasi-Fermi momentum divided by the square of the temperature. The fluid properties are characterized by shear and bulk viscosities proportional to the quasi-Fermi momentum over the enthalpy, with the bulk viscosity being approximately twice the shear viscosity due to its higher sensitivity to interactions.

Speaker: Jianing Li (Central China Normal University)

18:10 Reception

Wednesday, 27 November

Plenary

66 The physics program and the project status of Super Tau Charm Facility

Speaker: Yangheng Zheng

67 Hadron productions in the BESIII experiment

The BESIII experiment locates at the BEPCII e^+ e^- collider in Beijing, China, running in a center-of-mass energy range from 1.8 GeV to 4.95 GeV. After 16 years of successful running of the experiment since 2009, BESIII has accumulated a large statistics of electron-positron annihilation sample, such as data set at J/ψ, ψ(2S) and ψ(3770) peaks, and fine scan data between 1.8 GeV and 4.95 GeV. From these samples, BESIII has produced many interesting results in studying the mechanism of the hadron production in the energy region below 5 GeV, which corresponds to the non-perturbative QCD region. The topics include the inclusive single hadron production, Collins asymmetry in two hadron spin correlations, R values and baryon form factors in threshold pair productions. In this talk, the BESIII progress of QCD studies will be reported and the future prospects will be discussed.

Speaker: Xiao-Rui Lyu (University of Chinese Academy of Sciences)

68 China Hyperon-Nuclear Spectrometer (CHNS)

Speaker: Yuxiang Zhao

10:30 Tea Break

Plenary

69 Spin alignments of vector mesons in high energy reactions

Speaker: Zuotang Liang

70 Parton structure of heavy meson from Lattice QCD

Speaker: Wei Wang

71 Probing Meson Structure via Lattice QCD: Electromagnetic Form Factors at High Momenta and Generalized Parton Distributions

Speaker: Hengtong Ding

12:30 Lunch

Parallel-1

72 Insights into Proton Structure from a Light-Front QCD Hamiltonian

Speaker: Chandan Mondal

73 Structure of Lightest Nuclei in the Visible Universe on the Light Front

Speaker: Satvir Kaur

74 Energy-momentum tensor distribution for transversely polarized nucleons

We study the spatial distributions of the energy-momentum tensor (EMT) for transversely polarized nucleons in the elastic frame (EF), a general reference frame that bridges the Breit frame (rest frame) and the infinite momentum frame (IMF). As the longitudinal momentum, $P_{z}$, increases, the spin-dependent contributions are induced in the EF energy and EF longitudinal normal force distributions, derived from the matrix elements $\widehat{T}^{00}$ and $\widehat{T}^{33}$, respectively. In contrast, in the EF longitudinal momentum distribution, associated with the matrix element $\widehat{T}^{03}$, the spin-independent contributions are induced as $P_{z}$ increases. These induced contributions lead to distortions in each distribution. In the IMF, the spin-dependent contributions vanish, while the spin-independent ones remain, resulting in a perfect monopole structure in the EF energy, EF longitudinal momentum, and EF longitudinal normal force distributions for the transversely polarized nucleon.

Speaker: Ho-Yeon Won (CPHT, CNRS, École Polytechnique)

Parallel-2

75 Concerning pion structure using continuum Schwinger function methods

As the theory of quantum chromodynamics has unfolded, the pion has come to be understood as Nature’s most fundamental Nambu-Goldstone boson. It is attached to chiral symmetry, which is dynamically broken, quite probably as a corollary of emergence of hadron mass. Continuum Schwinger function methods are well suited to tackling the pion. This presentation describes the theoretical developments on pion structure, thereby providing challenges and opportunities for modern and anticipated high-luminosity, high-energy facilities - JLab at 22GeV, the AMBER project at CERN, and electron ion colliders in the USA and China - and surveys the developments in global phenomenological fits and lattice regularised QCD, enabling the picture of the pion to be drawn.

Speaker: Minghui Ding (Nanjing University)

76 From pion to dipion light-cone distribution amplitudes

As the lightest and simplest hadron composited by valence quarks, pion meson and the involved channels are usually treated as the benchmarks of measurements, which requires the theoretical calculations based on the knowledge of its inner structure to achieve at a high accuracy. How precise do we know the pion meson light-cone distribution amplitudes (LCDAs) ? In this talk I will report the recent study of the first few coefficients and the chiral mass by the data-driven dispersion relation with the electromagnetic form factor. Followed I will furtherly go to the LCDAs of dipion system where the double expansion coefficients B_nl^I would be discussed. I would like to conclude the talk with the phenomena in heavy flavor decays.

Speaker: Shan Cheng (Hunan University)

77 Towards Precise Hadron Tomography from Lattice QCD

In the past few years, there has been rapid progress in both theoretical developments and lattice calculations of the partonic structure of hadrons. In this talk, I will present some recent results aimed at achieving precise hadron tomography using lattice QCD.

Speaker: Jianhui Zhang (CUHK-Shenzhen)

Parallel-3

78 The hadron energy-momentum tensor in momentum space

We study the energy-momentum tensor of spin-0 and spin-1/2 hadrons in momentum space. We parametrize this object in terms of so-called gravitational transverse-momentum distributions, and we identify in the quark sector the relations between the latter and the usual transverse-momentum distributions. Focusing on particular components of the energy-momentum tensor, we study momentum densities, flux of inertia and stress distribution in momentum space, revealing part of the wealth of physical information that can be gained from higher-twist transverse-momentum distributions

Speaker: Qintao Song

79 Non-diagonal DVCS and $N \to N^*$ transition GPDs.

Transition GPDs describe matrix elements of nonlocal partonic QCD operators between ground and excited baryon states and provide new tools for quantifying and interpreting the structure of baryon resonances in QCD.
We consider a description of non-diagonal Deeply Virtual Compton Scattering process involving a transition between anucleon and a nucleon resonance in the pion-nucleon system within the framework of transition GPDs. We address the physical content of $N → N^*$ and $N\to \Delta$ transition GPDs, review the existing theoretical models and present theoretical estimates of related observables for the kinematic conditions corresponding to the experimental studies at JLab@12GeV. We also discuss the perspective of exploring resonance production with help of transition GPDs and consider the application of the Froissart-Gribov projections to study excitation of nucleon resonances by means of spin-$J$ QCD probes.

Speaker: Kirill Semenov-Tyan-Shanskiy (Kyungpook National University, Daegu, Korea)

80 Hadron structure in two dimensional QCD

The meson's boundstate equation in two dimensional QCD under large Nc limit (QCD₂) are exactly solvable in both light-front quantization and equal time quantization. In the meanwhile, QCD₂ captures some key features of realistic QCD in four dimension, such as color confinement, nonzero quark condensate. QCD₂ become an ideal theoretical laboratory for investigate theoretical method dealing with hadrons' structure from a field theory first-principle approach, such as Large Momentum Effective Theory, NRQCD factorization. We present the QCD₂ investigation of nonperturbative quantities: e.g. light-cone/quasi PDF/GPD, (heavy quark) fragmentation function, intrinsic charm distribution and the energy decomposition of a hadron is also discussed.

Speaker: Xiaonu Xiong (Central South University)

15:30 Tea Break

Poster

ILCAC meeting

18:00 Buffet/ ILCAC dinner

81 Public Lecture

Speaker: James Vary

Thursday, 28 November

Gary McCartor award

82 Three-dimensional structure of the proton and Sivers asymmetry within the BLFQ framework

The three-dimensional internal structures of the proton play a central role in the upcoming electron-ion colliders, among which TMDs have received increasing concentrations. They depict the proton in three-dimensional momentum space, and, via TMD factorization and evolution, can be connected to the cross-section of SIDIS process. In this talk, we start with an effective Hamiltonian to calculate all eight leading-twist quark TMDs within the Basis Light-front Quantization framework. We expand the gauge link to the first order and use the famous OGE approximation. After investigating some properties of the obtained TMDs, we further compute the Sivers asymmetry of SIDIS process. We conclude this talk by comparing our calculations with the experimental measurements.

Speaker: Zhi HU

83 Gluon distributions in the proton in a light-front spectator model

I will present a light-front spectator model for the proton that incorporates the gluonic degree of freedom. The model is based on light-front wave functions modeled from the soft-wall anti–de Sitter/QCD prediction, which allows us to explore the gluonic structure within the proton. Using this model, we have successfully predicted key results for gluon transverse momentum distributions (TMDs) and generalized parton distributions (GPDs), providing valuable insights into the behavior of gluons. In this talk, I will discuss gravitational form factors, which are essential for understanding the internal distributions of mass, energy, pressure, and shear within the proton. These form factors offer important information about the mechanical properties of the proton, particularly those related to gluonic interactions. This talk will demonstrate how our model contributes to a deeper understanding of the fundamental forces and distributions that define hadronic matter.

Speaker: Dr Poonam Choudhary (IIT Bombay)

84 Quantum simulation of quark jet and gluon jet

In this work, we demonstrate quantum advantage for simulating dynamics of multiple particles in the (3+1)-d QCD Hamiltonian on the light front, especially in the high-energy physics phenomena of an incoming quark jet or gluon jet scattered on the nuclear medium. Using quantum simulation with direct encoding, we provide an universal framework to simulate jet particles, and it is efficient in both Hamiltonian operator and multiple gluon state representation. For the numerical results, we use quantum simulator to simulate on more than a hundred qubits and we observe jet momentum broadening and gluon radiation.

Speaker: Wenyang Qian (University of Santiago de Compostela)

10:30 Tea Break

Plenary

85 Bridge between QCD and Light-Front Quark Model

I will present a mass gap solution of the 1+1D QCD in the large Nc limit known as the ‘tHooft model to discuss a link between QCD and the Light-Front Quark Model (LFQM). I will illuminate the interpolation between the instant form dynamics and the light-front dynamics and discuss its utility in the computation of the parton distribution function (PDF). I will then illustrate the Bakamjian-Thomas construction of the LFQM exemplifying the recent resolution of the light-front zero-mode issue raised about a decade ago regarding the pion transverse momentum distributions (TMDs) beyond the leading twist.

Speaker: Chueng-Ryong Ji (North Carolina State University)

86 Parton Fragmentation Functions from NPC

Speaker: Hongxi Xing

87 A new kind of TMDs inspired by the factorization theorem

We introduce and explore a new type of $k_\perp$-dependent functions. The existence of this kind of TMDs has been stemmed from the factorization theorem and they are initiated by the interactions encoded in the corresponding correlators. In contrast to the well-known transverse momentum dependentfunction, the new functions can be associated with the collective alignment of quark spin vectors. Moreover, the new functions are sensitive to the transverse motion of partons inside hadrons, which are linked to the spin alignment of partons.

Speaker: Prof. Igor V. Anikin (JINR, Dubna & IMP, Lanzhou)

12:30 Lunch

Excursion (HIAF & EicC in the future)

18:00 Banquet

Friday, 29 November

Plenary

88 Covariant two-body currents in light front quantum mechanics

Light-front quantum mechanics is an alternative to light-front quantum
field theory for modeling strongly interacting systems at relativistic
energies. The advantages are that (1) rotational covariance is exact,
so there are no problems identifying states of a given spin or
applying arbitrary Poincar\'e transformations to these states (2) it
is possible to construct realistic models of strongly interacting
systems that reproduce experimental binding energies and phase shifts
(3) numerically exact calculations of bound and scattering states can
be performed (4) it has the same kinematic symmetries as light-front
field theory and (5) there are irreducible sets of kinematic
operators. The disadvantages are (1) there is no direct connection to
light-front quantum field theory so the dynamical models are
representation dependent (2) two-body currents required by current
covariance and current conservation are necessary, representation
dependent, and not unique. The lack of understanding on how to
construct dynamically consistent two-body currents is the most serious
problem with applications of light-front quantum mechanics to
calculations of electroweak observables at relativistic momentum
transfers. In this work I construct two-body currents consistent with
the dynamics by (1) representing the light-front Hamiltonian in the
Weyl representation (using the irreducible set of kinematic operators)
(2) replacing the light-front momentum operators by gauge covariant
derivatives and (3) extracting the coefficient of the term linear in
the vector potential. This provides a candidate for the two-body
current that is consistent with the dynamics that is determined by
requiring local gauge invariance in the Weyl representation.

Speaker: Wayne Polyzou (University of Iowa)

89 nucleon energy correlator

We introduce the concept of the nucleon energy correlators, a set of novel objects that encode the microscopic details of a nucleon, such as the parton angular distribution in a nucleon, the collinear splitting to all orders, as well as the internal transverse dynamics of the nucleon.

Speaker: Prof. Xiaohui Liu (Beijing Normal University)

90 Nucleon and pion structure in Minkowski space

I will review the application of few-body methods to explore the structure of light hadrons in Minkowski space. The description of the nucleon and pion are based on the solution of the Bethe-Salpeter equation in Minkowski space built with phenomenological kernels. For the proton, we will show results obtained with the projection onto the light-front of the Faddeev-Bethe-Salpeter equation, including the valence parton distribution and the image of the valence state on the null-plane. The results for the pion structure observables are computed from the solution of the Bethe-Salpeter equation in Minkowski space using the Nakanishi integral representation. Results for the pion charge form factor, including higher Fock-components will be shown, and compared to the valence one. We found that the charge radius of the higher Fock components is about a half femtometer. The image of the pion valence state onto the null-plane will be presented, as well as results for the PDF and transverse momentum distributions. Some future prospects of research along these lines will be provided.

Speaker: Prof. Tobias Frederico (Instituto Tecnologico de Aeronautica)

10:30 Tea Break

Plenary

91 Holographic spin alignment for vector mesons

We develop a general framework for studying the spin alignment ρ00 for flavorless vector mesons by using the gauge/gravity duality. Focusing on the dilepton production through vector meson decay, we derive the relation between production rates at each spin channel and meson's spectral function, which can be evaluated by holographic models for a strongly coupled system. As examples, we study ρ00 for J/ψ and ϕ mesons, induced by the relative motion to a thermal background, within the soft-wall model. We show that ρ00 in the helicity frame for J/ψ and ϕ mesons have positive and negative deviations from 1/3 at T=150 MeV, respectively, which consequently leads to different properties for their global spin alignments. Further comparisons with experimental data show qualitative agreement for spin parameters λθ and λφ in the helicity and Collins-Soper frames.

Speaker: Defu Hou (CCNU)

92 Trace Anomaly and Sigma Terms of Baryons from Lattice QCD

The origin of hadron masses remains a fundamental question in QCD. While most of the proton’s mass arises from strong interactions, with only a small fraction stemming from quark masses, it is natural to ask if this phenomenon extends to other baryons with heavier quark content. In this talk, we explore how quark masses and the trace anomaly contribute to the masses of baryons containing light, strange, and charm quarks. Our lattice calculations show that baryon masses align with experimental data to within 1%, with gluon trace anomaly contributions across baryons are similar within 10% assuming the anomalous dimension $\gamma_m\sim$ 0.3.

This study reveals a potential universality in trace anomaly contributions across baryons, shedding light on the underlying nonperturbative mechanisms responsible for hadronic mass generation.

Speaker: Bolun Hu

93 PDF of Deuteron-like Di-baryon system on Lattice QCD

We report a lattice QCD calculation of the parton distribution function (PDF) of a deuteron-like dibaryon system using large-momentum effective theory. The calculation is done on three Wilson Clover ensembles with a fixed lattice spacing a=0.105 fm and two pion masses. The lattice matrix elements are computed at proton momenta up to 2.46 GeV with the signal of high momentum modes being improved by applying the momentum smearing technique. The state-of-the-art renormalization, matching and extrapolation are then applied to obtain the final result of the light-cone PDF. A comparison between the result of the dibaryon system and the sum of the proton and neutron PDFs is also given.

Speaker: Mr Peng Sun (IMP)

12:30 Lunch

Plenary

94 Some recent progress in hard exclusive processes

Speaker: Yu Jia

95 Recent results on nucleon spin structure from RHIC

Speaker: Qinghua Xu

96 Generalized parton distributions of the proton from nonlocal chiral effective theory

Speaker: Ping Wang

15:30 Tea Break

Plenary

97 Light mesons in the Instanton Liquid Model on the light cone

I will briefly outline the current Stony Brook program to address the light mesons and hadrons on the light front, based on the current evidence of the topological nature of the QCD vacuum from lattice simulations. I will provide a detailed description of the light mesons: pions, kaons, rhos on the light front, using the instanton liquid model (ILM) of the QCD vacuum.

Speaker: Prof. Ismail Zahed (Stony Brook)

98 Relativistic $^3$He light-front wave function

Light-front (LF) wave function of a three-fermion system, forming a bound state with the total angular momentum $J=\frac{1}{2}$, is determined, in general, by 16 invariant components - in coincidence with number of combinations $2\times 2\times2\times2=16$, which spin projections of three constituents and their bound state are forming. Parity conservation, in contrast to a two-fermion system, does not reduce this number. Each component depends on five variables: on modules of two independent transverse momenta $\vec{k}_{1\perp}, \vec{k}_{2\perp}$ and angle between them as well as on the longitudinal variables $x_1,x_2$. Until recently, this complexity prevented the finding of this wave function. In the framework of the explicitly covariant version of the LF dynamics, we calculated for the first time the full relativistic $^3$He LF wave function (including all the components),
for one-boson exchange interaction, not using the potential approximation. In the non-relativistic domain, its five components dominate and are close to the non-relativistic ones. Their deviation beyond this domain and appearance of new eleven components is due to the relativistic effects, found in our work, which can influence the electromagnetic form factors and other observables.

This approach
can be generalized to nuclei with larger number of nucleons ($^4$He, etc).
With replacement of nucleons by quarks and with appropriate interaction between them, it is fully applicable to the LF nucleon wave function.

A similar project for the relativistic deuteron LF wave function was realized long ago. It predicted very successfully the deuteron electromagnetic form factors.

Speaker: V.A. Karmanov (Lebedev Physical Institute of Russian Academy of Sciences, Moscow)

99 Gravity as a probe of hadron structure

The energy momentum tensor (EMT) matrix elements appear in the moments of various parton distributions. The external gravity coupling to EMT provide the constraints to hadron structure due to equivalence principle, This provides the complementary aspect of Ji's sum rules and the possibility of its tests in the experiments with precise measurements of spin precession.

The notion of equivalence principle may be (approximately) valid for quarks and gluons separately. Such extension is discussed for tensor spin structure functions and Generalized Distribution Amplitudes of exotic hybrid mesons. The possible small violation of such an extension in the latter case may be related to the smallness of viscosity of quark-gluon matter, .

Speaker: Oleg Teryaev (JINR)

100 Closing

18:00 Buffet