Subtractive renormalization of chiral effective theory NN 
potentials up to next-to-next-to leading order

Chieh Jen Yang
Ohio University

We have developed a subtractive renormalization method with which we can
evaluate NN scattering phase shifts produced by the NN potential obtained at
leading, next-to-leading, and next-to-next-to-leading order (NNLO) in the
chiral effective theory. In this method the low-energy constants
associated with short-distance NN physics are eliminated from the
Lippmann-Schwinger equation (LSE) for the NN t-matrix, in favor of physical
observables. This allows to straightforwardly compute scattering phase
shifts for ultra-violet cutoffs of at least 10 GeV. We then perform detailed
analyses of several renormalization issues and determine the maximum cutoff
at which the use of an effective field NN potential in the LSE makes sense.