Speaker
Description
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.
