Phys. Rev. Lett. 93, 122001 (2004) [5 pages]

Measurement of the Generalized Polarizabilities of the Proton in Virtual Compton Scattering at Q2=0.92 and 1.76  GeV2

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G. Laveissière et al. Jefferson Lab Hall A Collaboration
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Received 23 December 2003; published 14 September 2004

We report a virtual Compton scattering study of the proton at low c.m. energies. We have determined the structure functions PLL-PTT/ϵ and PLT, and the electric and magnetic generalized polarizabilities (GPs) αE(Q2) and βM(Q2) at momentum transfer Q2=0.92 and 1.76  GeV2. The electric GP shows a strong falloff with Q2, and its global behavior does not follow a simple dipole form. The magnetic GP shows a rise and then a falloff; this can be interpreted as the dominance of a long-distance diamagnetic pion cloud at low Q2, compensated at higher Q2 by a paramagnetic contribution from πN intermediate states.


©2004 The American Physical Society

URL: http://link.aps.org/doi/10.1103/PhysRevLett.93.122001
DOI: 10.1103/PhysRevLett.93.122001
PACS: 13.60.Fz

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