PT Journal
AU Falkowski, A
   Gonzalez-Alonso, M
   Palavric, A
   Rodriguez-Sanchez, A
TI Constraints on subleading interactions in beta decay Lagrangian
SO Journal of High Energy Physics
JI J. High Energy Phys.
PY 2024
BP 091
EP 54pp
VL 02
IS 2
DI 10.1007/JHEP02(2024)091
LA English
DE Effective Field Theories; Hadronic Matrix Elements and Weak Decays; Effective Field Theories of QCD; SMEFT
AB We discuss the effective field theory (EFT) for nuclear beta decay. The general quark-level EFT describing charged-current interactions between quarks and leptons is matched to the nucleon-level non-relativistic EFT at the OMeV momentum scale characteristic for beta transitions. The matching takes into account, for the first time, the effect of all possible beyond-the-Standard-Model interactions at the subleading order in the recoil momentum. We calculate the impact of all the Wilson coefficients of the leading and subleading EFT Lagrangian on the differential decay width in allowed beta transitions. As an example application, we show how the existing experimental data constrain the subleading Wilson coefficients corresponding to pseudoscalar, weak magnetism, and induced tensor interactions. The data display a 3.5 sigma evidence for nucleon weak magnetism, in agreement with the theory prediction based on isospin symmetry.
ER