Effective Field Theory Approach To \vec{n} + \vec{p} -> d + \gamma At Threshold

Abstract

Previously, in an effective field theory formulated by us, we have carried out parameter-free calculations of a large number of low-energy two-nucleon properties. An experiment at the Institut Laue-Langevin is currently measuring spin-dependent effects in the polarized np capture process \vec{n}+\vec{p} -> d +\gamma at threshold. Noting that spin-dependent observables for this reaction are sensitive to terms of chiral orders higher than hitherto studied, we extend our effective theory approach to this process and make parameter-free predictions on the spin-dependent observables.