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arXiv · 0907.4671

Extraction of the strong neutron-proton mass difference from the charge symmetry breaking in pn-->d pi0

A. Filin·V. Baru·E. Epelbaum·J. Haidenbauer·C. Hanhart·A. Kudryavtsev·U. -G. Meißner
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Abstract

We perform a complete calculation of charge symmetry breaking effects for the reaction pn -> d pi0 at leading order in chiral perturbation theory. A new leading-order operator is included. From our analysis we extract δm_N^{str}, the strong contribution to the neutron-proton mass difference. The value obtained, δm_N^{str} = 1.5 \pm 0.8 (exp.) \pm 0.5 (th.) MeV, is consistent with the result based on the Cottingham sum rule. This agreement provides a non-trivial test of our current understanding of the chiral structure of QCD.

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A. Filin, V. Baru, E. Epelbaum, J. Haidenbauer, C. Hanhart, A. Kudryavtsev, U. -G. Meißner. 2009-10-28. Extraction of the strong neutron-proton mass difference from the charge symmetry breaking in pn-->d pi0. https://doi.org/10.1016/j.physletb.2009.10.069

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