Radiative capture reactions in lattice effective field theory

TL;DR

This paper presents a lattice effective field theory method to compute nuclear radiative capture reactions, demonstrating its effectiveness by calculating the neutron-proton capture process with results matching continuum calculations.

Contribution

It introduces a novel lattice approach for two-body capture reactions, specifically calculating the M1 contribution to neutron-proton radiative capture at low energies.

Findings

Good agreement with exact continuum results

Effective method for lattice calculations of capture reactions

Demonstrated on pionless effective field theory

Abstract

We outline a general method for computing nuclear capture reactions on the lattice. The method consists of two major parts. In this study we detail the second part which consists of calculating an effective two-body capture reaction on the lattice at finite volume. We solve this problem by calculating the two-point Green's function using an infrared regulator and the capture amplitude to a two-body bound state. We demonstrate the details of this method by calculating on the lattice the leading M1 contribution to the radiative neutron capture on proton at low energies using pionless effective field theory. We find good agreement with exact continuum results.