Speaker
Dr
Olga Lukina
(SINP MSU)
Description
The ratio of the exclusive electroproduction of psi(2S) and J/psi mesons has been
measured at HERA. The results are sensitive to the wave functions of the vector
mesons
and are compared to predictions of QCD-inspired models of vector-meson production.
Exclusive dijet production in diffractive deep inelastic scattering has been measured
at HERA. Cross sections are presented as a function of $\beta$, the Bjorken variable
defined with respect to the diffractive exchange and, in bins of $\beta$, as a function
of $\phi$, the angle between the $\gamma^{\star}$--dijet plane and the $\gamma^{\star}$--e plane in the
rest frame of the dijet final state. The results are compared to predictions from
models which are based on different assumptions about the nature of the diffractive
exchange.
The first measurement of exclusive photoproduction of rho mesons associated with
leading
neutrons with the H1 detector at HERA is also presented. The data are interpreted in
terms of two dominant contributions: diffractive proton dissociation channel and
elastic
production via virtual pion exchange.
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. 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
Olga Lukina
(SINP MSU)
