It is shown that baryon chiral perturbation theory can be employed to calculate the excited-state contamination in various nucleon observables due to two-particle nucleon-pion states. Leading order results are presented for the nucleon axial, tensor and scalar charge and three Mellin moments of parton distribution functions (quark momentum fraction, helicity and transversity moment). Taking into ... More

Analyses of LHC (and other!) experiments require robust and statistically accurate determinations of the structure of the proton, encoded in the parton distribution functions (PDFs). The standard description of hadronic processes relies on factorization theorems, which allow a separation of process-dependent short-distance physics from the universal long-distance structure of the proton. Trad ... More

We report on a lattice QCD calculation of the nucleon axial charge, $g_A$, using Mobius Domain-Wall fermions solved on the dynamical $N_f=2+1+1$ HISQ ensembles after they are smeared using the gradient-flow algorithm. The calculation is performed with three pion masses, $m_\pi\sim\{310,220,130\}$ MeV. Three lattice spacings ($a\sim\{0.15,0.12,0.09\}$ fm) are used with the heaviest pion mass, whi ... More