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arXiv · 1210.7777

Cottingham formula for the electromagnetic self-energy contribution to M_p - M_n

Andre Walker-Loud·Carl E. Carlson·Gerald A. Miller
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Abstract

We provide an update of the determination of the electromagnetic self-energy contribution to M_p - M_n based upon Cottingham's Formula. A technical oversight in the literature is uncovered: the application of the Cottingham Formula requires the use of a subtracted dispersion integral; an argument to evade the subtraction function was presented; the argument was based on false assumptions about the scaling violations of the parton model, a point first mentioned by J. C. Collins. We elucidate this point and utilize low-energy effective theory to relate the unknown subtraction function to the nucleon isovector magnetic polarizability. This allows us to provide the first reliable determination of dM = 1.30(03)(47) MeV [1].

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Andre Walker-Loud, Carl E. Carlson, Gerald A. Miller. 2012-10-29. Cottingham formula for the electromagnetic self-energy contribution to M_p - M_n. https://arxiv.org/abs/1210.7777

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