Lightcone and quasi distribution amplitudes for light octet and decuplet baryons

Generalized parton distributions (GPDs) are key quantities for the description of a hadron’s three-dimensional structure. They are the current focus of all areas of hadronic physics—phenomenological, experimental and theoretical, including lattice QCD. Synergies between these areas are desirable and essential to achieve precise quantification and understanding of the structure of, particularly, nucleons, as the basic ingredients of matter. In this paper, we investigate, for the first time, the numerical implementation of the pseudodistribution approach for the extraction of zero-skewness GPDs for unpolarized quarks. Pseudodistributions are Euclidean parton correlators computable in lattice QCD that can be perturbatively matched to the light-cone parton distributions of interest. Although they are closely related to the quasidistributions and come from the same lattice-extracted matrix elements, they are, however, subject to different systematic effects. We use the data previously utilized for quasi-GPDs and extend it with other momentum transfers and nucleon boosts, in particular a higher one (P3=1.67 GeV) with eightfold larger statistics than the largest one used for quasidistributions (P3=1.25 GeV). We renormalize the matrix elements with a ratio scheme and match the resulting Ioffe time distributions to the light cone in coordinate space. The matched distributions are then used to reconstruct the x dependence with a fitting . We investigate some systematic effects related to this procedure, and we also compare the results with the ones obtained in the framework of quasi-GPDs. Our final results involve the invariant four-momentum transfer squared (−t) dependence of the flavor nonsinglet (u−d) H and E GPDs. Published by the American Physical Society 2024

Generalized parton distributions from the pseudodistribution approach on the lattice

Bhattacharya,

Cichy,

Constantinou

et al. 2024

Power corrections to quasidistribution amplitudes of a heavy meson

Han,

Wang,

Zhang

et al. 2024

It has been recently demonstrated that light cone distribution amplitudes (LCDAs) for a heavy meson, defined in the heavy quark limit, can be extracted by simulating quasidistribution amplitudes on the lattice with a large meson momentum Pz. This extraction involves a two-step procedure. In the first step, the quasidistribution amplitudes are matched onto the QCD LCDAs in the large Pz limit. In the second step, the QCD LCDAs are matched onto the desired LCDAs defined in heavy quark effective theory. In this work, we present the mH2n/(Pz)2n and ΛQCD2/(xPz)2 and ΛQCD2/((1−x)Pz)2 corrections in the first step with mH being the heavy meson mass and x being the momentum fraction of the light quark. To account for mH2n/(Pz)2n corrections, we employ two methods: the moment relation that can provide mass corrections to all orders, and a leading-twist projector that gives the leading-order mass corrections. For the ΛQCD2/(Pz)2 corrections, we employ a renormalon model that addresses the renormalon ambiguity stemming from the divergence of the perturbative series. We adopt two parametrizations for QCD LCDAs to conduct a numerical analysis. The results suggest that these corrections are typically smaller than 20% in the region 0.2<x<0.8, and should be included in a precision analysis. These findings will serve as a valuable guide for future studies on heavy meson LCDAs, particularly in the context of lattice QCD, where accounting for such corrections is crucial for improving the accuracy and reliability of the results. Published by the American Physical Society 2024

Light-cone sum rules study on the purely nonfactorizable Λc+→Ξ0K+ decay

Shi,

Zhao

2024

We investigate the purely nonfactorizable Λc+→Ξ0K+ decay using light-cone sum rules. To extract the decay amplitudes, a three-point correlation function is defined and calculated at hadron and quark-gluon level, respectively. Both the W-exchange and the W-inward emission diagrams are considered in the quark-gluon level calculation, where the two-particle light-cone distribution amplitudes (LCDAs) of kaon are used as nonperturbative input. We obtain the decay amplitudes contributed from the twist-2 and twist-3 kaon LCDAs, respectively. The obtained P-wave amplitude is consistent with those predicted in the literature, while the S-wave one is much smaller. This significant difference between the S- and P -wave amplitudes leads to small up-down spin asymmetry, close to the experimental measurement. Published by the American Physical Society 2024