Details

Autor(en) / Beteiligte

• Valderrama, M Pavón
• Phillips, D R

Titel

Power counting of contact-range currents in effective field theory

Ist Teil von

• Physical review letters, 2015-02, Vol.114 (8), p.082502-082502, Article 082502

Ort / Verlag

United States: American Physical Society

Erscheinungsjahr

2015

Link zum Volltext

Quelle

American Physical Society Journals

Beschreibungen/Notizen

• We analyze the power counting of two-body currents in nuclear effective field theories (EFTs). We find that the existence of nonperturbative physics at low energies, which is manifest in the existence of the deuteron and the ^{1}S_{0} NN virtual bound state, combined with the appearance of singular potentials in versions of nuclear EFT that incorporate chiral symmetry, modifies the renormalization-group flow of the couplings associated with contact operators that involve nucleon-nucleon pairs and external fields. The order of these couplings is thereby enhanced with respect to the naive-dimensional-analysis estimate. Consequently, short-range currents enter at a lower order in the chiral EFT than has been appreciated up until now, and their impact on low-energy observables is concomitantly larger. We illustrate the changes in the power counting with a few low-energy processes involving external probes and few-nucleon systems, including electron-deuteron elastic scattering and radiative neutron capture by protons.