Novel evaluation of the two-pion contribution to the nucleon isovector form factors

Belushkin, M. A.; Meissner, U.G.; Hammer, H. W.

doi:10.1016/j.physletb.2005.12.053

Journal Article

PreJuSER-54801

Novel evaluation of the two-pion contribution to the nucleon isovector form factors

Belushkin, M. A. ; Hammer, H. W. ; Meissner, U. G.FZJ*

2006
North-Holland Publ. Amsterdam

Physics letters / B 633, 507 - 511 (2006) [10.1016/j.physletb.2005.12.053]

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Please use a persistent id in citations: http://hdl.handle.net/2128/10610 doi:10.1016/j.physletb.2005.12.053

Abstract: We calculate the two-pion continuum contribution to the nucleon isovector spectral functions drawing upon the new high statistics measurements of the pion form factor by the CMD-2, KLOE, and SND Collaborations. The general structure of the spectral functions remains unchanged, but the magnitude increases by about 10%. Using the updated spectral functions, we calculate the contribution of the two-pion continuum to the nucleon isovector form factors and radii. We compare the isovector radii with simple p-pole models and illustrate their strong underestimation in such approaches. Moreover, we give a convenient parametrization of the result for use in future form factor analyses. (c) 2005 Elsevier B.V. All rights reserved.

Keyword(s): nucleon: form factor ; isovector ; dispersion relation ; spectral representation: two-pion ; pi: form factor ; numerical calculations ; interpretation of experiments: Frascati Stor