Speaker
Daniel McDonald
(R)
Description
In part to search for a possible critical point (CP) in the phase
diagram of hot nuclear matter, a beam energy scan was performed at
the Relativistic Heavy-Ion Collider at Brookhaven National
Laboratory. The STAR experiment collected significant Au+Au data
sets at beam energies, $\sqrt{\rm s_{\rm NN}}$, of 7.7, 11.5, 19.6,
27, 39, 62.4 and 200 GeV. Lattice and phenomenological calculations
suggest that the presence of a CP might result in divergences of the
thermodynamic susceptibilities and correlation lengths [1,2]. The
statistical moments of the multiplicity distributions of particles
reflecting conserved quantities, {\it e.g.} net-charge and
net-strangeness, are expected to depend sensitively on these correlation lengths, making them attractive tools for the search of
a possible critical point.
In this talk, the centrality and beam energy dependence of the
statistical moments of the net-charge multiplicity distributions will
be presented. The observables studied include the lowest four
statistical moments (mean, variance, skewness, kurtosis), products of
these moments, and the intensive normalized cumulants [2]. The
measured moments of the net-Kaon and total-pion multiplicity
distributions will also be presented. These will be compared to the
predictions from approaches lacking critical behavior, such as the
Hadron Resonance Gas model [3] and Poisson statistics.
References
[1] M. Cheng {\it et al.}, Phys. Rev. D 79, 074505 (2009).
[2] C. Athanasiou {\it et al.}, Phys. Rev. D 82, 074008 (2010),
M. Stephanov, Phys. Rev. Lett. 107, 052301 (2011).
[3] F. Karsch and K. Redlich, Phys. Lett. B 695, 136 (2011).
Author
Daniel McDonald
(R)
Peer reviewing
Paper
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