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Electromagnetic Contribution to the Proton-Neutron Mass Splitting

Nuclear Theory 2015-03-05 v1 High Energy Physics - Lattice High Energy Physics - Phenomenology

Abstract

We study the electromagnetic contribution to the proton-neutron mass splitting by combining lattice simulations and the modified Cottingham sum rule of Walker-Loud, Carlson and Miller. This analysis yields an estimate of the isovector nucleon magnetic polarizability as a function of pion mass. The physical value, obtained by chiral extrapolation to the physical pion mass, is βpn=(1.12±0.40)×104 fm3\beta_{p-n}=(-1.12 \pm 0.40)\times 10^{-4}\ \mathrm{fm}^3, which is in agreement with the empirical result, albeit with a somewhat smaller error. As a result, we find δMpnγ=1.04±0.11 MeV\delta M^{\gamma}_{p-n}=1.04 \pm 0.11\ \mathrm{MeV}, which represents a significant improvement in precision.

Keywords

Cite

@article{arxiv.1406.4579,
  title  = {Electromagnetic Contribution to the Proton-Neutron Mass Splitting},
  author = {A. W. Thomas and X. G. Wang and R. D. Young},
  journal= {arXiv preprint arXiv:1406.4579},
  year   = {2015}
}
R2 v1 2026-06-22T04:40:59.563Z