Lattice Calculation of Parton Distribution Function from LaMET at Physical Pion Mass with Large Nucleon Momentum

Mar 12, 2018
6 pages
e-Print:
Report number:
  • MSUHEP-18-003,
  • MIT-CTP/4991,
  • MIT-CTP-4991

Citations per year

2017201920212023202405101520
Abstract: (arXiv)
We present a lattice-QCD calculation of the unpolarized isovector parton distribution function (PDF) using ensembles at the physical pion mass with large proton boost momenta Pz{2.2,2.6,3.0}P_z \in \{2.2,2.6,3.0\}~GeV within the framework of large-momentum effective theory (LaMET). In contrast to our previous physical-pion PDF result, we increase the statistics significantly, double the boost momentum, increase the investment in excited-state contamination systematics, and switch to γt\gamma_t operator to avoid mixing with scalar matrix elements. We use four source-sink separations in our analysis to control the systematics associated with excited-state contamination. The one-loop LaMET matching corresponding to the new operator is calculated and applied to our lattice data. We detail the systematics that affect PDF calculations, providing guidelines to improve the precision of future lattice PDF calculations. We find our final parton distribution to be in reasonable agreement with the PDF provided by the latest phenomenological analysis.
Note:
  • 6 pages, 4 figures
  • parton: distribution function
  • isovector
  • quark: mass dependence
  • nucleon: momentum
  • quantum chromodynamics
  • lattice field theory
  • numerical calculations
  • effective field theory
  • excited state
  • quark: staggered