Conveners
Poster presentation: Poster presentation
- Mingze Sun
Polarized hadron beams provide a powerful tool for exploring interactions that are unobservable with unpolarized beams, particular for testing symmetry violations. Axions are leading particle candidates for dark matter. They were originally introduced to solve the strong CP problem and have also appeared in various extensions to the Standard Model (SM). At low axion masses,...
In odd-A nuclei, for excitation energy greater than proton or neutron pairing gaps, either a proton-proton or a neutron-neutron pair can break to generate a three-quasiparticle (3qp) quadruplet, on each member of which one rotational band is formed. Rotational bands and associated high-spin phenomena are one of the important aspects of nuclear structure. The dynamics of these high-spin...
Lead-205 initially looks like a very promising candidate to be used as a chronometer for the early Solar System due to its unique position among astrophysically short-lived radionuclides as an s-only isotope probing the termination of the s process [1]. Unfortunately, the 2.3 keV $1/2^-$ first excited state in $^{205}$Pb reduces the half-life in stellar environments by around 6 orders of...
In recent years, we have constructed and built a free-electron target for electron-ion collision experiments in the heavy-ion storage rings ESR and CRYRING at GSI/FAIR, where the ribbon-shaped electron beam crossed the ion beam with an interaction angle of 90°. The electron target is one of the major new experimental installations of the SPARC collaboration within the FAIR project [1]. The...
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Using the $B\rho$-defined isochronous mass sprectrometry technique, we report the first determination of the $^{23}$Si, $^{26}$P, $^{27}$S, and $^{31}$Ar masses and improve the precision of the $^{28}$S mass by a factor of 11. Our measurements confirm that these isotopes are bound and fix the location of the proton dripline in P, S, and Ar. We find that the mirror energy differences of the...
We report microscopic many-body calculations indicating that rotational bands based on nuclear scissors vibrations exhibit systematic splitting between neighboring spin states (ΔI = 2 bifurcation) in which the magnitude of the moment of inertia oscillates between states having even and odd spins. We show that this unexpected result is caused by self-organization of the deformed proton and...
In order to pursue improved mass accuracy as a means for investigating r-process mechanisms, a position-sensitive Schottky cavity detector has been developed. This is a successor to the Schottky Cavity detectors implemented at GSI for isochronous mass spectroscopy [1]. These detectors have high resolution ($dM/M\approx10^{-6}$), however this deteriorates as the isochronous condition worsens...
All superdeformed (SD) bands of Pb isotopes have been systematically studied in
the context of SU(3) dynamical symmetry of the Interacting Boson Model (IBM) for
the first time. For each SD band in Pb isotopes, the level spins are suggested. The
model parameters are determined using a computer-based program to minimize the root
mean square (RMS) deviation of the calculated SU(3) symmetry...
The measurement of betatron tunes is important in the studies of beam dynamics in circular accelerators. Here, we report a new method to extract the fractional tune values using revolution times of single ions stored for a few hundred turns in a heavy-ion storage ring utilizing a single time-of-flight detector. The experiment was done at the experimental Cooler Storage Ring (CSRe) in Lanzhou....
Laser cooling of bunched Li-like O5+ ion beams with an energy of 275.7 MeV/u was successfully achieved at the storage ring CSRe in Lanzhou, China [1, 2]. In the experiment, the laser cooling processes were recorded in real time by employing a high-sensitivity Schottky resonator. By detuning the bunching frequency, the longitudinal beam dynamics of the laser cooling processes have been...
A novel high precision position-sensitive TOF detector has been designed for the future isochronous mass measurement experiments at Cooler Storage Ring (CSRe) and Spectrometer Ring (SRing). Compared with the existing time-of-flight detector, another MCP perpendicular to the carbon foil was added in the new design. When an ion passing through the carbon foil, it can induce signals in both the...
Radiative recombination (RR), $e^-+A^{q+}→A^{(q-1)+} (nl)+hν$, is a crucial process in various fields of fundamental and applied physics. However, an apparent discrepancy, namely RR enhancement, has been found between the rate coefficients measured at very low collision energies in the electron cooler of the storage ring and those predicted by widely recognized theoretical models [1–5].
In...
Double-β (ββ) decay is a rare transition process between nuclei (A, Z) and (A, Z + 2). There may exist two modes of this decay. One is the two-neutrino ββ (2νββ) decay with
the emission of two antineutrinos. The other mode is the neutrinoless ββ (0νββ) decay, which is a lepton-number-violating nuclear process and occurs only if neutrinos are their own antiparticles, i.e., the Majorana...
Isochronous Mass Spectrometry is a practical approach for studying decays of short-lived isomers. However,solely relying on the time stamps between the isomer and ground state does not provide clear sign of decay. To address this issue, we proposed a method for extracting decay time point by analyzing the residuals of time stamps within a window of (20 $\mu$s, 180 $\mu$s) after the start of...
The challenge of masses measurement of exotic nuclei is up to the limits of nuclear existence which are characterized by low production cross-sections and short half-lives.The isochronous mode of the Spectrometer Ring at the High Intensity heavy-ion Accelerator Facility project in China (HIAF-SRing) offers the capacity for such measurements.However, many factors limit the revolution time...
The empirical rules often lead towards the development and corroboration of new theories and played a key role in the development of physics [1]. In this article, we presented a most comprehensive validation of Gallagher and Moszkowski (GM) rules for odd-odd and even-even nuclei and their generalization to three quasiparticle states formed due to coupling of angular momenta of valence nucleons...
In conventional isochronous mass spectrometry (IMS) performed on a storage ring, the precision of mass measurements for short-lived nuclei depends on the accurate determination of the revolution times ($T$) of stored ions. However, the resolution of $T$ inevitably deteriorates due to the magnetic rigidity spread of the ions, limiting the mass-resolving power. In this study, we used the...
We present several particle detectors dedicated for the Rare-RI Ring (R3) storage ring. Since R3 in the cyclotron facility stores only a single ion at each injection, conventional beam diagnostics such as beam profile monitors and wire scanners are inapplicable. Thus, we have developed unique detectors as follows,
- Revolution time monitor, “delta-ray” detector which directly measures...
The established storage ring mass spectrometry at the current operational HIRFL-CSR facility in Lanzhou has demonstrated its efficacy in accurately measuring the masses of short-lived nuclei that are far from beta stability. With the advent of the High Intensity heavy-ion Accelerator Facility (HIAF), the beam intensity is anticipated to be three orders of magnitude higher than what can...
The precise measurements of lifetime of unstable nuclei, along with the investigation of exotic decay modes in highly charged ions, stands at the forefront of nuclear physics research. The Schottky mass spectrometer based on heavy ion cooler storage rings is one of the advanced tools for conducting relevant research, capable of realizing non-destructive and long-term measurements of ions...
The sensitivity of the r-process rare-earth peak abundances to nuclear masses has been studied in different astrophysical scenarios. The most impactful nuclei lie along the r-process paths at r-process freeze-out and at the time when the neutron-capture timescale is approximately 3 times of the β-decay timescale, corresponding to the onset and completion of rare-earth peak formation,...
Determination of the true feeding intensities (Iβ) in β-decay of fission products is very important in addressing the reactor antineutrino anomaly and modeling the reactor decay heat. β-decay measurements with high-resolution but low-efficiency detectors may affect by the Pandemonium effect. This effect may lead to underestimation of the feeding to high excited levels, thus systematically...
The NICA collider will be used for both collider experiments with heavy ions and light polarized particles. The different charge-to-mass ratio is essential in magneto-optics design. To achieve high luminosity sufficient beam lifetime must be guaranteed. Transition energy crossing must also be solved for both modes.
The ground-state mass excess (ME) of the Tz=-2 dripline nuclei 22Al,26P and 28S are measured for the first time using the newly-developed Bρ-defined isochronous mass spectrometry at the cooler storage ring in Lanzhou. The new ME value of 22Al allows to determine the mirror energy differences (MEDs) in the 22Al-22F pair. Besides, The ground-state mass excess of the Tz=-5/2 nuclei 23Si,27S and...
The newly developed software, Nucleus++, is an advanced tool for displaying basic nuclear physics properties from Nubase and integrating comprehensive mass information for each nuclide from Atomic Mass Evaluation. Additionally, it allows users to compare experimental nuclear masses with predictions from diferent mass models. Building on the success and learning experiences of its predecessor,...
To achieve a high signal-to-noise ratio and better temporal resolution, which could yield important physical information about fast processes, an improved design of a longitudinally sensitive resonant Schottky cavity pickup with copper coat for the high-intensity heavy ion accelerator facility (HIAF) project is reported. The final goal of the pickup is to detect single proton. The new 308 MHz...
he role of nuclear fission in the r-process nucleosynthesis occurring in neutron star mergers is studied. Current theoretical nuclear physics models([1][2][3]) are based on different assumptions on the fission barrier for different fission channels (spontaneous fission, neutron-induced fission, β-delayed fission, etc). In this work, the
nuclear reaction network calculation based on a...
As an essential terminal of the HIAF project, the Spectrometer Ring will be used to collect the secondary ion beams for the isochronous mass measurement. The transition energy γt can be adjusted to match the energy of beams. To decrease the effect of momentum deviation on the revolution time, the second-order isochronous condition should be corrected by the sextupole magnets installed in the...
The linear polarization of hard x-ray photons is an important observable for precision tests of QED on the dynamics of high-Z atomic systems at particle accelerators like GSI/FAIR as well as synchrotron facilities like DESY/PETRA3.
For the design of a Compton Polarimeter covering a wide energy range, we followed the concept of a telescope configuration with thick planar semiconductor...
Nuclei around 132Sn play significant role in nuclear structure and nuclear astrophysics. Their nuclear structure properties, like mass (A), half life (T1/2),Pn&P2n values, are essential to reproduce ther-process abundances and to understand the origin of the elements in the universe [1,2]. By investigating the nuclear configuration of states around the 132Sn core, the extension of the magic...
Empirical proton-neutron interactions, V_pn, in mirror nuclei are analyzed systematically using the updated ground-state atomic masses,[Eur. Phys. J. A 59, 27 (2023); Phys. Rev. Lett. , 192501 (2023)]. If masses of bound nuclei only are utilized, the corresponding V_pn values for mirror nuclei are found to be equal within one standard deviation of σ=31 keV.
However, when a proton-unbound...
Spontaneous and induced fission studies provide a rich source of new insights into the nuclear structure of neutron-rich nuclei over long isotopic chains. These nuclei span a wide range from Z~32 to 64 with a variety of nuclear shape and structure information including single particle and collective degrees of freedom. As part of a study of the evolution of the structure of in this A~100...
Rare charm decays offer the possibility to search for signals beyond the Standard Model in the up-quark sector. We review the rare charm decays to final states containing leptons and mesons. The high luminosity and excellent precision of current experiments enable the study of rare charm decay under many conditions. The different experimental scenarios allow those studies in e+e− and pp...
The High Intensity heavy ion Accelerator Facility (HIAF) is under construction in Huizhou City of China. It aims at constructing the next generation edge research platform for nuclear physics, astrophysics, atomic physics, high energy density physics, and beam applications. The Booster Ring (BRing) is the essential component which accumulates beams from iLinac by novel two plane painting and...
Differential cross sections for $p$-$^{56}\textrm{Ni}$ and $p$-$^{58}\textrm{Ni}$ elastic scattering, measured at low momentum transfer and at projectile energies of about 400 MeV/u with beams stored in the Experimental Storage Ring (ESR) at GSI, Darmstadt [1], have been analyzed up to $|t| = 0.06$ (GeV/c)$^2$ applying the model-independent Sum-of-Gaussians (SOG) method based on the Glauber...
