Nucleon Mass and Charges with Lattice Quantum Chromodynamics

  • April 29, 2021, 2:30 pm US/Central
  • Yin Lin, Fermilab/University of Chicago
  • Will Jay
  • slides
  • video

Theoretical understandings of the neutrino-nucleus cross sections are critical for constraining neutrino parameters in future neutrino oscillation experiments such as DUNE and Hyper-K. For neutrino energies at around 1 GeV, uncertainties in the nucleon axial form factor, which parameterizes the weak response of a neutron or proton as a function of the four momentum transfer, limit the cross-section precision in nuclear models. The form factor is difficult to measure experimentally, so a first-principle calculation with lattice quantum chromodynamics (QCD) provides an alternative method to obtain a systematically improvable result without proposing new experiments.

In this talk, I will introduce the basic methodologies of lattice QCD and show how to calculate nucleon observables. In particular, I will focus on calculations of the nucleon mass and charges with the staggered fermion discretization, which is one of the most efficient, if not the most efficient, lattice fermions to simulate. Theoretical difficulties had prevented calculating nucleon observables with staggered fermions. Here I will provide a solution to the problem based on the generalized Wigner-Eckart theorem and present numerical results to validate our answers.