Speaker
Andrzej Rybicki
(H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences)
Description
In this talk we review our studies of spectator-induced electromagnetic (EM) effects on charged
pion emission in ultrarelativistic heavy ion collisions. These effects are found to consist
in the electromagnetic *charge splitting* of pion directed flow as well as very large
distortions in spectra and ratios of produced charged particles. As it emerges from our
analysis, they offer sensitivity to the actual distance $d_E$ between the pion formation zone at
freeze-out and the spectator matter. As a result, this gives a new possibility of studying
the space-time evolution of dense and hot matter created in the course of the collision.
Having established that $d_E$ traces the longitudinal evolution of the system and therefore
rapidly decreases as a function of pion rapidity, we investigate the latter finding in view
of pion feed-over from intermediate resonance production. As a result we obtain a first
estimate of the pion decoupling time from EM effects which we compare to existing HBT data.
We conclude that spectator-induced EM interactions can serve as a new tool for studying the
space-time characteristics and longitudinal evolution of the system. We discuss the future
perspectives for this activity on the basis of existing and future data from NICA,
NA61/SHINE, STAR and ALICE experiments.
Authors
Andrzej Rybicki
(H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences)
Antoni Szczurek
(H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences)
