Speaker
Dr.
Peter Bussey
(Glasgow University)
Description
The photoproduction of isolated photons, both inclusive and together
with a jet, has been measured with the ZEUS detector at HERA using an
integrated luminosity of 374 pb-1. A variety of kinematic variables
that are sensitive to different aspects of the event dynamics are studied.
Cross sections are given in terms of the collinearity of the photon and
the jet, the fraction of the proton energy involved in the interaction,
and the pseudorapidity difference between the photon and the jet. These
and other variables are also studied for different ranges of
x_gamma^{meas}, the fraction of the photon energy involved in the
interaction, in order to enhance the direct and resolved photon components
of the process. Differential cross sections are also presented for
inclusive isolated-photon production as functions of the transverse energy
and pseudorapidity of the photon. Higher-order theoretical calculations
are compared to the results. Measurements of normalised cross sections
for the production of photons and neutrons at very small angles with
respect to the proton beam direction in deep inelastic scattering are
presented as a function of the Feynman variable xF and of the
centre-of-mass energy of the virtual photon-proton system, W. The data are
taken with the H1 detector and correspond to an integrated luminosity of
131 pb-1. The measurement is restricted to photons and neutrons in the
pseudorapidity range eta > 7.9. To test the Feynman scaling hypothesis
the W dependence of the xF dependent cross sections is investigated.
Predictions of deep inelastic scattering models and of models for hadronic
interactions of high energy cosmic rays are compared to the measured cross
sections.
Primary author
Dr.
Peter Bussey
(Glasgow University)
