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Sep 24 – 29, 2023
US/Eastern timezone

Moments of proton GPDs from the OPE of nonlocal quark bilinears up to NNLO

Sep 27, 2023, 11:22 AM
18m
Meeting Room 3-4 (Durham Convention Center)

Meeting Room 3-4

Durham Convention Center

Talk 3D Structure of the Nucleon: GPDs and Form Factors 3D Structure of the Nucleon: GPDs and Form Factors

Speaker

Xiang Gao

Description

We present a lattice QCD determination of Mellin moments of unpolarized generalized parton distributions (GPDs) of the proton from an analysis of the quasi-GPD matrix elements within the short-distance factorization framework. We perform our calculation on an $N_f$=2+1+1 twisted mass fermions ensemble with a clover improvement at lattice spacing $a=0.093$ fm and a pion mass of $m_\pi=260$ MeV. Focusing on the zero-skewness case, the iso-vector and iso-scalar quasi GPDs are calculated from the $\gamma_0$ definition, as well as a recently proposed Lorentz-invariant definition. We utilize data on both symmetric and asymmetric kinematic frames, which allows us to obtain the Mellin moments for several values of the momentum transfer, $-t$, in the range 0.17 to $2.77~\rm{GeV}^2$. We use the ratio scheme with leading-twist factorization formula and perturbatively calculated matching coefficients up to the next-next-to-leading order (NNLO) to extract Mellin moments of GPDs. We estimated the moments of GPDs up to the fifth ones for the first time. The impact parameter space interpretation of the GPD moments is discussed, which provides insights into the spatial distribution of unpolarized quarks and their correlations in the transverse plane of an unpolarized or transversely polarized proton.

Primary authors

Andreas Metz (Physics Department, Temple University, Philadelphia) Fernanda Steffens (University of Bonn) Joshua Miller (Temple University) Krzysztof Cichy (Adam Mickiewicz University) Martha Constantinou (Temple University) Peter Petreczky (BNL) Shohini Bhattacharya (BNL) Swagato Mukherjee (Brookhaven National Laboratory) Xiang Gao Yong Zhao (Argonne National Laboratory)

Presentation materials