5-11 February 2017
Hyatt Regency Chicago
America/Chicago timezone

ALICE measurements on $\rho^0$ photoproduction in Pb-Pb ultra-peripheral collisions

Not scheduled
2h 30m
Hyatt Regency Chicago

Hyatt Regency Chicago

151 East Wacker Drive Chicago, Illinois, USA, 60601
Board: A06


David Horak (Czech Technical University (CZ))


The powerful photon fluxes of relativistic nuclei provide a possibility
to study photonuclear and two-photon interactions in ultra-peripheral collisions (UPC)
where the nuclei do not overlap and no strong nuclear interactions occur.
Within Vector-meson Dominance Model (VDM), $\rho^0$ contribution prevails in QCD photon structure
function and gamma+A -> $\rho^0$ +A process in heavy-ion UPC is a tool to test, so-called, black disk regime
where the target nuclei appears like a black disk and the total $\rho^0$ +A cross section reaches its limit.
RHIC and first LHC results have deviated from some Glauber+VDM calculations, which thus call for new data.
ALICE reports measurements on $\rho^0$ photoproduction cross sections
in Pb-Pb UPC with data taken at sqrt(NN)=2.76 TeV and new measurements with the data
taken at sqrt(NN)=5.02 TeV. The mid-rapidity cross section of coherent $\rho^0$ photoproduction is measured,
and it is compared to theoretical models. The measurements are presented for various nuclei
breakup scenarios - without electromagnetic dissociation (EMD) of nuclei and with single or mutual EMD as well.

Preferred Track Initial State Physics and Approach to Equilibrium
Collaboration ALICE

Primary author

David Horak (Czech Technical University (CZ))

Presentation materials