Study of the effective transverse momentum of partons in the proton using prompt photons in photoproduction at HERA
arXiv:hep-ex/0104001 · doi:10.1016/S0370-2693(01)00615-3
Abstract
The photoproduction of prompt photons, together with an accompanying jet, has been measured with the ZEUS detector at HERA using an integrated luminosity of 38.6 pb^{-1}. A study of the effective transverse momentum, k_T, of partons in the proton, as modelled within the framework of the PYTHIA Monte Carlo, gives a value of k_T = 1.69+/-0.18 ^{+0.18}_{-0.20} GeV for the photon-proton centre-of-mass energy range 134 < W < 251 GeV. This result is in agreement with the previously observed trend in hadron-hadron scattering for k_T to rise with interaction energy.
20 pages including 4 figures; accepted by Physics Letters B