Production of jets and single particles at large transverse momentum in photon-photon collisions

Abstract

Photon-photon collisions will be a copious source of jets and single particles produced with large transverse momentum in e/sup +/e/sup -/ storage rings. These jets and single particles have topological properties which allow them to be easily distinguished from e/sup +/e/sup -/ annihilation events. They arise from several sources: (a) quark exchange in ..gamma gamma.. ..-->.. qq-bar, (b) quantum-chromodynamics (QCD) induced processes such as ..gamma../sub 1/ ..-->.. qq-bar, with qq scattering via vector-gluon exchange, and (c) differential cross sections proportional to p/sub T//sup -6/ and p/sub T//sup -8/ at fixed x/sub T/ = 2p/sub T//..sqrt..s-bar and fixed theta/sub c.m./ characteristic of the constituent-interchange model (CIM) picture. In particular, we predict Edsigma/d/sup 3/p (e/sup +/e/sup -/ ..-->.. e/sup +/e/sup -/ + jet + X) approx. (1 - x/sub T/)/sup 2/p/sub T//sup -6/ nb GeV/sup 4/ for p/sub T/ > 2 GeV/c, characteristic of the CIM subprocess ..gamma..q ..-->.. ..pi..q. Remarkably, the jet-trigger cross sections Edsigma/d/sup 3/p (..gamma gamma.. ..-->.. jet + X) turn out to be asymptotically scale-free and independent of ..cap alpha../sub c/(p/sub T//sup 2/) when perturbative QCD contributions to all orders are included.