Radiative Neutron Capture on Lithium-7

TL;DR

This paper presents a model-independent calculation of the radiative neutron capture on lithium-7 using halo effective field theory, highlighting the dependence on the p-wave effective range parameter and fitting low energy data accurately.

Contribution

The work introduces a model-independent approach to calculate the cross section, directly relating it to scattering parameters and explicitly analyzing the impact of the p-wave effective range.

Findings

The cross section depends critically on the p-wave effective range parameter r.

A single parameter fit accurately describes low energy data.

The effective field theory approach reduces model dependence in calculations.

Abstract

The radiative neutron capture on lithium-7 is calculated model independently using a low energy halo effective field theory. The cross section is expressed in terms of scattering parameters directly related to the S-matrix element. The cross section depends on the poorly known p-wave effective range parameter r. This constitutes the leading order uncertainty in traditional model calculations. It is explicitly demonstrated by comparing with potential model calculations. A single parameter fit describes the low energy data extremely well and yields r = -1.47 fm^{-1}.