title: Exclusive photoproduction of hard dijets and magnetic susceptibility of the QCD vacuum.
abstract: We argue that coherent production of hard dijets by linearly polarized real photons can provide direct evidence for chirality violation in hard processes, the first measurement of the magnetic susceptibility of the quark condensate and the photon distribution amplitude. It can also serve as a sensitive probe of the generalized gluon parton distribution. Numerical calculations are presented for HERA kinematics.
authors.affiliation: Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany.
authors.forename: V M
authors.initials: VM
authors.lastname: Braun
authors.forename: S
authors.initials: S
authors.lastname: Gottwald
authors.forename: D Yu
authors.initials: DY
authors.lastname: Ivanov
authors.forename: A
authors.initials: A
authors.lastname: Schäfer
authors.forename: L
authors.initials: L
authors.lastname: Szymanowski