Bingwei Long, C. -J. Yang
Continuing our effort to build a consistent power counting for chiral nuclear
effective field theory, we discuss the subleading contact interactions, or
counterterms, in the singlet channels of nucleon-nucleon scattering, with
renormalization group invariance as the constraint. We argue that the rather
large cutoff error of the leading amplitude requires O(Q) of the low-energy
approximation to be non-vanishing, contrary to Weinberg's original power
counting. This, together with the ultraviolet divergences of two pion exchanges
in distorted-wave expansion, leads to enhancement of the 1S0 counterterms and
results in a pionless theory-like power counting for the singlet channels.
View original:
http://arxiv.org/abs/1202.4053
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