4 research outputs found
Exclusive production of large invariant mass pion pairs in ultraperipheral ultrarelativistic heavy ion collisions
The cross section for exclusive production of and
meson pairs in ultrarelativistic heavy ion collisions is calculated for LHC
energy 3.5 TeV taking into account photon-photon mechanism.
We concentrate on the production of large two-pion invariant masses where the
mechanism of the elementary process is not fully
understood. In order to include a size of nuclei we perform calculation in the
impact-parameter equivalent photon approximation (EPA). Realistic charge
densities are used to calculate charged form factor of Pb nucleus and
to generate photon fluxes associated with ultrarelativistic heavy ions.
Sizeable cross sections are obtained that can be measured at LHC. The cross
section for elementary is calculated in the
framework of pQCD Brodsky-Lepage (BL) mechanism with the distribution amplitude
used to descibe recent data of the BABAR collaboration on pion transition form
factor, using hand-bag mechanism advocated to describe recent Belle data as
well as and -channel meson/reggeon exchanges. We present distributions
in two-pion invariant mass as well as the pion pair rapidity for the nuclear
process.Comment: 13 pages, 10 figure