Nucleon Tomography and Generalized Parton Distribution at Physical Pion Mass from Lattice QCD

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 approximate to 0.09 fm and volume 64(3) x 96. We use momentum-smeared sources to improve the signal at nucleon boost momentum P-z approximate to 2.2 GeV and report results at nonzero momentum transfers in [0.2, 1.0] GeV2. 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 xi = 0 are presented, along with the three-dimensional nucleon tomography and impact parameter-dependent distribution for selected Bjorken x at mu = 3 GeV in a modified minimal subtraction scheme.

Automated summary

This study presents the first lattice calculation of the nucleon isovector unpolarized generalized parton distribution at the physical pion mass, using a lattice ensemble with highly improved staggered quarks and momentum-smeared sources to enhance signal. Results at nonzero momentum transfers and three-dimensional distributions at xi=0 are shown, along with impact parameter-dependent distribution for selected Bjorken x values.