Rearranging pionless effective field theory

Abstract

We point out a redundancy in the operator structure of the pionless effective field theory, EFT(π̵), which dramatically simplifies computations. This redundancy is best exploited by using dibaryon fields as fundamental degrees of freedom. In turn, this suggests a new power counting scheme which sums range corrections to all orders. We explore this method with a few simple observables: the deuteron charge form factor, np→d γ, and Compton scattering from the deuteron. Unlike EFT(π̵), the higher-dimension operators involving electroweak gauge fields are not renormalized by the s-wave strong interactions, and therefore do not scale with inverse powers of the renormalization scale. Thus, naive dimensional analysis of these operators is sufficient to estimate their contribution to a given process.