The Electromagnetic Self-Energy Contribution to M_p - M_n and the Isovector Nucleon Magnetic Polarizability
We update the determination of the isovector nucleon electromagnetic self-energy, valid to leading order in QED. A technical oversight in the literature concerning the elastic contribution to Cottingham's formula is corrected and modern knowledge of the structure functions is used to precisely determine the inelastic contribution. We find {delta}M{sub p-n}{sup {gamma}} = 1.30(03)(47) MeV. The largest uncertainty arises from a subtraction term required in the dispersive analysis, which can be related to the isovector magnetic polarizability. With plausible model assumptions, we can combine our calculation with additional input from lattice QCD to constrain this polarizability as: {beta}{sub p-n} = -0.87(85) x 10{sup -4} fm{sup 3}.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC05-06OR23177
- OSTI ID:
- 1043288
- Report Number(s):
- JLAB-THY-12-1574; DOE/OR/23177-2191; arXiv:1203.0254; PRLTAO; TRN: US1203054
- Journal Information:
- Physical Review Letters, Vol. 108, Issue 23; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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