Radiative Corrections to Superallowed π½ Decays in Effective Field Theory
Radiative Corrections to Superallowed π½ Decays in Effective Field Theory
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Abstract
The accuracy of ππ’β’π determinations from superallowed π½ decays critically hinges on control over radiative corrections. Recently, substantial progress has been made on the single-nucleon, universal corrections, while nucleus-dependent effects, typically parametrized by a quantity πΏNS, are much less well constrained. Here, we lay out a program to evaluate this correction from effective field theory (EFT), highlighting the dominant terms as predicted by the EFT power counting. Moreover, we compare the results to a dispersive representation of πΏNS and show that the expected momentum scaling applies even in the case of low-lying intermediate states. Our EFT framework paves the way toward abΒ initio calculations of πΏNS and thereby addresses the dominant uncertainty in ππ’β’π.
