Journal of East China Normal University(Natural Science) ›› 2020, Vol. 2020 ›› Issue (2): 90-97.doi: 10.3969/j.issn.1000-5641.201922008

• Physics and Electronics • Previous Articles     Next Articles

A study of nucleon-nucleon scattering in covariant chiral effective field theory at the two-loop level

SUN Jin, YANG Jifeng   

  1. School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
  • Received:2019-03-25 Published:2020-03-16

Abstract: The amplitude of the two-loop level in N-N(nucleon-nucleon) scattering is calculated using covariant chiral effective theory. Based on the skeleton of the box diagram, the two-loop diagram results from the correction of pion self-energy. Two subtraction schemes will be employed for comparison: $\overline {{\rm{MS}}}$ and ${\rm{E}}\overline {{\rm{MS}}}$. The loop amplitude obtained with $\overline {{\rm{MS}}}$ contains terms that violate chiral power counting rules; with ${\rm{E}}\overline {{\rm{MS}}}$, the results are entirely chiral contributions with the exception of non-local “anomalous” ones that must be retained.

Key words: covariant chiral effective field theory, $\scriptstyle\overline {{\rm{MS}}}$ scheme, $\scriptstyle{\rm{E}}\overline {{\rm{MS}}}$ scheme, chiral power counting rules

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