Shell model description of the 14C dating beta decay with Brown-Rho-scaled NN interactions

TL;DR

This paper uses shell model calculations with Brown-Rho-scaled NN interactions to accurately describe the beta decay of 14C, improving agreement with experimental data by incorporating medium modifications.

Contribution

It introduces a modified Bonn-B potential with Brown-Rho scaling into shell model calculations, successfully reproducing key features of 14C beta decay.

Findings

Gamow-Teller matrix element vanishes at 85% nuclear matter density

Improved splitting between 14N states with medium-modified potential

Transition strengths align with recent experimental results

Abstract

We present shell model calculations for the beta-decay of the 14C ground state to the 14N ground state, treating the states of the A=14 multiplet as two 0p holes in an 16O core. We employ low-momentum nucleon-nucleon (NN) interactions derived from the realistic Bonn-B potential and find that the Gamow-Teller matrix element is too large to describe the known lifetime. By using a modified version of this potential that incorporates the effects of Brown-Rho scaling medium modifications, we find that the GT matrix element vanishes for a nuclear density around 85% that of nuclear matter. We find that the splitting between the (J,T)=(1+,0) and (J,T)=(0+,1) states in 14N is improved using the medium-modified Bonn-B potential and that the transition strengths from excited states of 14C to the 14N ground state are compatible with recent experiments.