PT Journal
AU Alvarado, F
   Alvarez-Ruso, L
TI Light-quark mass dependence of the nucleon axial charge and pion-nucleon scattering phenomenology
SO Physical Review D
JI Phys. Rev. D
PY 2022
BP 074001
EP 13pp
VL 105
IS 7
DI 10.1103/PhysRevD.105.074001
LA English
AB The light-quark mass dependence of the nucleon axial isovector charge (gA) has been studied up to nextto-next-to-leading order, O(p4), in relativistic chiral perturbation theory using extended-on-mass-shell renormalization, without and with explicit Delta(1232) degrees of freedom. We show that in the Delta-less case, at this order, the flat trend of gA(MN) exhibited by state-of-the-art lattice QCD (LQCD) results cannot be reproduced using low energy constants extracted from pion-nucleon elastic and inelastic scattering. A satisfactory description of these LQCD data is only achieved in the theory with Delta. From this fit, we report gA(MN(phys)) = 1.260 1 0.012, close to the experimental result, and d16 = -0.88 1 0.88 GeV-2, in agreement with its empirical value. The large uncertainties are of theoretical origin, reflecting the difference between O(p3) and O(p4) that still persists at large MN in presence of the Delta.
ER