Unpolarized gluon distribution in the nucleon from lattice quantum chromodynamics

Tanjib Khan , Raza Sabbir Sufian , Joseph Karpie , Christopher J. Monahan , Colin Egerer , Bálint Joó , Wayne Morris , Kostas Orginos , Anatoly Radyushkin , David G. Richards , Eloy Romero , Savvas Zafeiropoulos (1)

1 CPT - Centre de Physique Théorique - UMR 7332

In this study, we present a determination of the unpolarized gluon Ioffe-time distribution in the nucleon from a first principles lattice quantum chromodynamics calculation. We carry out the lattice calculation on a ${32}^3\times 64$ ensemble with a pion mass of 358 MeV and lattice spacing of 0.094 fm. We construct the nucleon interpolating fields using the distillation technique, flow the gauge fields using the gradient flow, and solve the summed generalized eigenvalue problem to determine the gluonic matrix elements. Combining these techniques allows us to provide a statistically well-controlled Ioffe-time distribution and unpolarized gluon parton distribution function. We obtain the flow time independent reduced Ioffe-time pseudodistribution and calculate the light-cone Ioffe-time distribution and unpolarized gluon distribution function in the $\overline{\mathrm{MS}}$ scheme at $\mu =2\mathrm{GeV}$, neglecting the mixing of the gluon operator with the quark singlet sector. Finally, we compare our results to phenomenological determinations.

Mots clés: quark: singlet; pi: mass; gluon: operator; gluon: distribution function; nucleon; flow; lattice; lattice field theory; GeV; gauge field theory; light cone; mixing

Domaines: Physique des Hautes Energies - Réseau [hep-lat]; Physique des Hautes Energies - Expérience [hep-ex]; Physique des Hautes Energies - Phénoménologie [hep-ph]; Physique Nucléaire Expérimentale [nucl-ex]; Physique Nucléaire Théorique [nucl-th]

Tanjib Khan, Raza Sabbir Sufian, Joseph Karpie, Christopher J. Monahan, Colin Egerer, et al.. Unpolarized gluon distribution in the nucleon from lattice quantum chromodynamics. Physical Review D, 2021, 104 (9), pp.094516. ⟨10.1103/PhysRevD.104.094516⟩. ⟨hal-03313186⟩