Speaker
Antoni Szczurek
(Institute of Nuclear Physics)
Description
We estimate the electromagnetic effect of the spectator charge on
azimuthal anisotropies observed in heavy ion collisions. For peripheral
Pb+Pb reactions at the top energy of the CERN Super Proton Synchrotron,
$\sqrt{s_{NN}}=17.3$ GeV, we predict this effect to bring very large
distortions to the observed directed flow, $v_1$, of positive and
negative pions emitted close to beam rapidity. The overall magnitude of
this effect is comparable to values of $v_1$ reported by the WA98 experiment.
We argue that also at lower rapidities, the spectator induced
electromagnetic effect may result in the splitting of values of $v_1$
observed for positive and negative pions.
Such a splitting is visible also in the data reported by the STAR
Collaboration from the RHIC Beam Energy Scan.
Both effects are sensitive to the space-time scenario assumed for
pion emission. Therefore, the electromagnetic splitting brings new
information on the collision dynamics. The presentation will be based
on our recent preprint [1].
1) A. Rybicki and A. Szczurek, arXiv:1303.7354, submitted to
Phys. Rev. {\bf C}.
Author
Antoni Szczurek
(Institute of Nuclear Physics)
Co-author
Dr
Andrzej Rybicki
(Institute of Nuclear Physics, Krakow)
