Second-order perturbation theory for 3He and pd scattering in pionless EFT

TL;DR

This paper develops a second-order perturbation theory within pionless effective field theory to accurately describe 3He and proton-deuteron scattering, including Coulomb effects, with good convergence and precise force fixing.

Contribution

It introduces a second-order perturbative expansion around the unitarity limit in pionless EFT, incorporating Coulomb effects and fixing three-nucleon forces for improved scattering predictions.

Findings

Converges well at second order

Includes Coulomb effects perturbatively

Accurately predicts proton-deuteron scattering

Abstract

This work implements pionless effective field theory with the two-nucleon system expanded around the unitarity limit at second order perturbation theory. The expansion is found to converge well. All Coulomb effects are treated in perturbation theory, including two-photon contributions at next-to-next-to-leading order. After fixing a three-nucleon force to the 3He binding energy at this order, proton-deuteron scattering in the doublet S-wave channel is calculated for moderate center-of-mass momenta.