Measurement of Three-jet Distributions in Photoproduction at HERA
arXiv:hep-ex/9810046 · doi:10.1016/S0370-2693(98)01360-4
Abstract
The cross section for the photoproduction of events containing three jets with a three-jet invariant mass of M_3J > 50 GeV has been measured with the ZEUS detector at HERA. The three-jet angular distributions are inconsistent with a uniform population of the available phase space but are well described by parton shower models and O(alpha alpha_s^2) pQCD calculations. Comparisons with the parton shower model indicate a strong contribution from initial state radiation as well as a sensitivity to the effects of colour coherence.
13 pages including 5 figures