Eur. Phys. J. C (2003) 28: 249-259
https://doi.org/10.1140/epjc/s2003-01166-8

Theoretical Physics

Hard exclusive baryon-antibaryon production in two-photon collisions

C.N. Yang Institute for Theoretical Physics, SUNY Stony Brook, Stony Brook, NY 11794-3840, USA
Institut für Theoretische Physik, Universität Graz, Universitätsplatz 5, 8010 Graz, AT , Austria

Received: 4 December 2002
Published online: 14 March 2003

Abstract

We study baryon pair production in two-photon collisions, $\gamma \gamma \rightarrow B \bar{B}$, within perturbative quantum chromodynamics, treating baryons as quark-diquark systems. We extend previous work within the same approach by treating constituent-mass effects systematically by means of an expansion in the small parameter (mass/photon energy). Our approach enables us to give a consistent description of the cross sections for all octet baryon channels. Adopting the model parameters from foregoing work, we are able to reproduce the most recent large-momentum-transfer data from LEP for the $p\bar{p}$, $\Lambda\bar{\Lambda}$, and $\Sigma^0\bar{\Sigma}^0$ channels in a quite satisfactory way. We also briefly address the crossed process for the proton channel, $\gamma p \rightarrow \gamma p$.