Ab-initio calculations of charge symmetry breaking in the A=4 hypernuclei

TL;DR

This paper uses ab-initio calculations with chiral EFT potentials to accurately reproduce charge symmetry breaking effects in A=4 hypernuclei, matching recent experimental data and demonstrating the importance of realistic interaction models.

Contribution

First ab-initio four-body calculations showing that realistic interaction models can reproduce observed charge symmetry breaking in A=4 hypernuclei.

Findings

Reproduced the binding energies of Lambda-4H and Lambda-4He

Demonstrated the ability to reproduce charge symmetry breaking splittings

Showed the dependence on momentum cutoff in the calculations

Abstract

We report on ab-initio NCSM calculations of the A=4 mirror Lambda hypernuclei Lambda-4H and Lambda-4He, using the Bonn-Juelich LO chiral EFT YN potentials plus a CSB Lambda0--Sigma0 mixing vertex. In addition to reproducing rather well the 0+ (g.s.) and 1+ (exc.) binding energies, these four-body calculations demonstrate for the first time that the observed CSB splitting of mirror levels, reaching hundreds of keV for 0+ (g.s.), can be reproduced using realistic theoretical interaction models, although with a non-negligible momentum cutoff dependence. Our results are discussed in relation to recent measurements of the Lambda-4H (0+ g.s.) binding energy [MAMI A1 Collaboration, Phys. Rev. Lett. 114, 232501 (2015)] and the Lambda-4He (1+ exc.) excitation energy [J-PARC E13 Collaboration, Phys. Rev. Lett. 115, 222501 (2015)].