Speaker
Antoni Szczurek
(Institute of Nuclear Physics)
Description
We calculate cross sections for diphoton production
in (semi)exclusive $PbPb$ collisions, relevant for the LHC.
The calculation is based on equivalent photon approximation in
the impact parameter space.
The cross sections for elementary $\gamma \gamma \to \gamma \gamma$
subprocess are calculated including two different mechanisms.
We take into account box diagrams
with leptons and quarks in the loops.
In addition, we consider a vector-meson dominance (VDM-Regge) contribution
with virtual intermediate hadronic (vector-like) excitations of the photons.
We get much higher cross sections in $PbPb$ collisions
than in earlier calculation from the literature.
This opens a possibility to study the $\gamma \gamma \to \gamma \gamma$
(quasi)elastic scattering at the LHC.
We present many interesting differential distributions which could
be measured by the ALICE, CMS or ATLAS Collaborations at the LHC.
We study whether a separation or identification of different components
(boxes, VDM-Regge) is possible. We find that the cross section for elastic
$\gamma \gamma$ scattering could be measured in the heavy-ion collisions
for subprocess energies smaller than $W_{\gamma\gamma} \approx 15-20$~GeV.
My presentation will be based on [1].
[1] M. K{\l}usek-Gawenda, P. Lebiedowicz and A. Szczurek,
arXiv:1601.07001.
Primary author
Antoni Szczurek
(Institute of Nuclear Physics)
