Doubly virtual Compton scattering and the beam normal spin asymmetry

dc.creatorGorchtein, Mikhail
dc.date2005-12-08
dc.date2006-01-17
dc.date.accessioned2026-07-07T10:44:28Z
dc.date.available2026-07-07T10:44:28Z
dc.descriptionWe construct an invariant basis for Compton scattering with two virtual photons (VVCS). The basis tensors are chosen to be gauge invariant and orthogonal to each other. The properties of the corresponding 18 invariant amplitudes are studied in detail. We consider the special case of elastic VVCS with the virtualities of the initial and final photons equal. The invariant basis for VVCS in this orthogonal form does not exist in the literatur. We furthermore use this VVCS tensor for a calculation of the beam normal spin asymmetry in the forward kinematics. For this, we relate the invariant amplitudes to the helicity amplitudes of the VVCS reaction. The imaginary parts of these latter are related to the inclusive cross section by means of the optical theorem. We use the phenomenological value of the transverse cross section $σ_T\sim0.1$ mbarn and the Callan-Gross relation which relates the longitudinal cross section $σ_L$ to the transverse one. The result of the calculation agrees with an existing calculation and predicts the negative values of the asymmetry $B_n$ of the order of 4-6 ppm in the energy range from 6 to 45 ppm and for very forward angles.
dc.description13 pages, 2 figures, revtex, submitted to Phys. Rev. C; new version: two figures added, typos corrected
dc.identifierhttps://arxiv.org/abs/hep-ph/0512106
dc.identifierhttp://arxiv.org/abs/hep-ph/0512106
dc.identifierPhys.Rev.C73:035213,2006
dc.identifierdoi:10.1103/PhysRevC.73.035213
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/182603
dc.subjectHigh Energy Physics - Phenomenology
dc.subjectNuclear Theory
dc.titleDoubly virtual Compton scattering and the beam normal spin asymmetry
dc.typetext

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