Martin J. Savage

A New expansion for nucleon-nucleon interactions

Abstract We introduce a new and well defined power counting for the effective field theory describing nucleon-nucleon interactions. Because of the large NN scattering lengths it differs from other applications of chiral perturbation theory and is facilitated by introducing an unusual subtraction scheme and renormalization group analysis. Calculation to subleading order in the expansion can be done analytically, and we present the results for both the 1 S 0 and 3 S 1 − 3 D 1 channels.

Two nucleon systems from effective field theory

Abstract We elaborate on a new technique for computing properties of nucleon-nucleon interactions in terms of an effective field theory derived from low energy NN scattering data. Details of how the expansion is carried out to higher orders are presented. Analytic formulae are given for the amplitude to subleading order in both the 1 S 0 and 3 S 1 − 3 D 1 channels.

Nucleon-Nucleon Scattering from Effective Field Theory

We perform a non-perturbative calculation of the 1S0 NN scattering amplitude, using an effective field theory (EFT) expansion. The expansion we advocate is a modification of what has been used previously; it is not a chiral expansion in powers of mπ. We use dimensional regularization throughout, and the MS renormalization scheme; our final result depends only on physical observables. We show that the EFT expansion of the quantity |p| cotθ(p) converges at momenta much greater than the scale A that characterizes the derivative expansion of the EFT Lagrangian. Our conclusions are optimistic about the applicability of an EFT approach to the quantitative study of nuclear matter.

Towards a Perturbative Theory of Nuclear Forces

NT@UW-01-06 LBNL 47692 RBRC-186 Towards a Perturbative Theory of Nuclear Forces S.R. Beane a , P.F. Bedaque b , M.J. Savage a,c , and U. van Kolck d,e arXiv:nucl-th/0104030 v1 9 Apr 2001 a Department of Physics, University of Washington, Seattle, WA 98195 b Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 c Jefferson Laboratory, 12000 Jefferson Avenue, Newport News, VA 23606 Department of Physics, University of Arizona, Tucson, AZ 85721 d e RIKEN-BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973 Abstract We show that an expansion of nuclear forces about the chiral limit is formally consistent and is equivalent to KSW power counting in the 1 S 0 channel and Weinberg power counting in the 3 S 1 − 3 D 1 coupled channels. Numerical evidence suggests that this expansion converges. The feasibility of making contact between nuclear physics and lattice-QCD simulations is discussed.

Evidence for a bound H dibaryon from lattice QCD.

We present evidence for the existence of a bound H dibaryon, an I=0, J=0, s=-2 state with valence quark structure uuddss, at a pion mass of m(π)∼389  MeV. Using the results of lattice QCD calculations performed on four ensembles of anisotropic clover gauge-field configurations, with spatial extents of L∼2.0, 2.5, 3.0, and 3.9 fm at a spatial lattice spacing of b(s)∼0.123  fm, we find an H dibaryon bound by B(∞)(H)=16.6±2.1±4.6  MeV at a pion mass of m(π)∼389  MeV.

Nonperturbative contributions to the inclusive rare decays B-->Xs gamma and B-->Xsl+l-

We discuss nonperturbative contributions to the inclusive rare

Two nucleons on a lattice

B

Hyperon–nucleon scattering from fully-dynamical lattice QCD

decays

Variation of fundamental couplings and nuclear forces

B\to X_s\gamma

Extra dimensions, SN1987a, and nucleon-nucleon scattering data

and