Abstract
We present a measurement of the total cross section for , with one photon quasireal and the other a spacelike photon of mass squared . Results are presented as a function of and the center-of-mass energy , with the range extending from 0.2 to 60 Ge, and in the range from 2 to 10 GeV. The data were taken with the TPC/Two-Gamma facility at the SLAC storage ring PEP, which was operated at a beam energy of 14.5 GeV. The cross section exhibits a gentle falloff with increasing . Its dependence is shown to be well described by an incoherent sum of vector-meson and pointlike scattering over most of the observed range. Agreement at high is improved if a minimum- cutoff (motivated by QCD) is imposed on the pointlike contribution.
- Received 11 September 1989
DOI:https://doi.org/10.1103/PhysRevD.41.2667
©1990 American Physical Society