J. Phys. Colloques
Volume 35, Numéro C2, Mars 1974Colloque international sur les collisions photon-photon dans les anneaux de stockage électron-positron / International colloquium on photon-photon collisions in electron-positron storage rings
|Page(s)||C2-122 - C2-123|
J. Phys. Colloques 35 (1974) C2-122-C2-123
"Quark parton model, light-cone expansions and virtual γγ-scattering"V. L. CHERNYAK and V. G. SERBO
Institute for Mathematics, Novosibirsk (USSR)
Here a model like that of Landshoff and Polkinghorne is presented. Within it a method is formulated which allows one for producing an arbitrary number of currents to obtain an expansion when one of the distances is small. The model is applied to the study of the forward γγ-scattering in the region of deep virtuality of one of the photons : - q21 >> m20, q22 is arbitrary (q1 and q2 are photon momenta) (q1 + q2)2 = s m0 ~ 1 GeV. For the absorptive part of the amplitude the following results have been obtained : a) In the region m20 << s << p2 q2/m20 the contribution of the box-diagram is dominant, and therefore amplitude is known. The eight independent invariant amplitudes of the process reduce to the two unknown functions in all the other cases. These last ones depend on two combinations of three independent variables s, q21 and q22 only. b) In the region s0 ~ m20 these combinations are s/m20 and (q21 - q22)/(q21 + q22). c) In the region s > q21 q22/m20 these combinations are s/q21 and q22/m20. At q22/m20 >> 1 the dependence on only argument s m20/q21 q22 is left and at s m20/q21 q22 >> 1 the Regge behaviour takes place.