Speaker
Dr
Mariola Klusek-Gawenda
(Institute of Nuclear Physics, Polish Academy of Sciences)
Description
We will discuss diphoton semi(exclusive) production
in ultraperipheral $PbPb$ collisions at energy of $\sqrt{s_{NN}}=$ 5.5 TeV (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:
\begin{itemize}
\item box diagrams with leptons and quarks in the loops and
\item a vector-meson dominance (VDM-Regge) contribution
with virtual intermediate hadronic (vector-like) excitations of the photons.
\end{itemize}
We get much higher cross sections in $PbPb$ collisions ($310$ nb)
than in earlier calculation from the literature $35 \pm 7$ nb\footnote{D. d'Enterria and G.G. da Silveira,
Phys. Rev. Lett. \textbf{111} (2013) 080405}.
This opens a possibility to study the $\gamma \gamma \to \gamma \gamma$
(quasi)elastic scattering at the LHC.
We will present many interesting differential distributions which could
be measured by the ALICE, CMS or ATLAS Collaborations.
We will show the range of energy $W_{\gamma\gamma}$ where elastic
$\gamma \gamma$ scattering could be measured in the heavy-ion collisions.
\vspace{2cm}
This talk will be based on our recent paper:\\
- M. K{\l}usek-Gawenda, P. Lebiedowicz and A. Szczurek, arXiv/nucl-th:1601.07001.
Primary author
Dr
Mariola Klusek-Gawenda
(Institute of Nuclear Physics, Polish Academy of Sciences)
Co-authors
Prof.
Antoni Szczurek
(Institute of Nuclear Physics, Polish Academy of Sciences)
Dr
Piotr Lebiedowicz
(Institute of Nuclear Physics, Polish Academy of Sciences)