Nucleon Tomography and Generalized Parton Distribution at Physical Pion Mass from Lattice QCD
Huey-Wen Lin
Abstract
We present the first lattice calculation of the nucleon isovector unpolarized generalized parton distribution at the physical pion mass using a lattice ensemble with $2+1+1$ flavors of highly improved staggered quarks generated by the MILC Collaboration, with lattice spacing $a\ensuremath{\approx}0.09\text{ }\text{ }\mathrm{fm}$ and volume ${64}^{3}\ifmmode\times\else\texttimes\fi{}96$. We use momentum-smeared sources to improve the signal at nucleon boost momentum ${P}_{z}\ensuremath{\approx}2.2\text{ }\text{ }\mathrm{GeV}$ and report results at nonzero momentum transfers in $[0.2,1.0]\text{ }\text{ }{\mathrm{GeV}}^{2}$. Nonperturbative renormalization in a regularization-independent momentum-subtraction scheme is used to obtain the quasidistribution before matching to the light-cone generalized parton distributions. The three-dimensional distributions $H(x,{Q}^{2})$ and $E(x,{Q}^{2})$ at $\ensuremath{\xi}=0$ are presented, along with the three-dimensional nucleon tomography and impact parameter--dependent distribution for selected Bjorken $x$ at $\ensuremath{\mu}=3\text{ }\text{ }\mathrm{GeV}$ in a modified minimal subtraction scheme.