Seminar über Physik der Starken Wechselwirkung, 2Probing the hot QCD matter with event-by-event fluctuations"

by Dr. Mesut Arslandok (Universität Heidelberg - Physikalisches Institut)

PH 3344 (Seminarraum Theorie) (TUM, Physik-Department)

PH 3344 (Seminarraum Theorie)

TUM, Physik-Department

James-Franck-Str. 1, Garching

In a thermal system, fluctuations of particle yields are directly encoded in the
equation of state of the system under the study. By measuring event-by-event
fluctuations over an ensemble of events via cumulants or moments of particle
multiplicity distributions, one can study the freeze-out conditions in heavy-ion collisions
and clarify their relation to the QCD phase transition. The thermodynamic
susceptibilities, which can be calculated within the Lattice QCD (LQCD) framework,
describe the response of a thermalized system to external conditions and they can be
directly related to the cumulants of conserved charges such as electric charge,
strangeness, and baryon number.
In this talk, I will discuss recent studies of measured event-by-event fluctuation
signals, as well as several experimental challenges, such as particle-misidentification,
detection efficiency losses and volume fluctuations. These experimental results will be
confronted with the corresponding signals from dynamical models, and the dependence
of fluctuation measurements on phase-space coverage of detected particles will be
addressed in view of the calculations from Lattice QCD and the Hadron Resonance Gas