https://doi.org/10.1140/epja/i2016-16250-7
Regular Article - Theoretical Physics
Net baryon fluctuations from a crossover equation of state
1
School of Physics & Astronomy, University of Minnesota, 55455, Minneapolis, MN, USA
2
National Superconducting Cyclotron Laboratory, Michigan State University, 48824, East Lansing, MI, USA
* e-mail: kapusta@physics.umn.edu
Received:
13
May
2016
Accepted:
3
July
2016
Published online:
23
August
2016
We have constructed an equation of state which smoothly interpolates between an excluded-volume hadron resonance gas at low energy density to a plasma of quarks and gluons at high energy density. This crossover equation of state agrees very well with lattice calculations at both zero and nonzero baryon chemical potential. We use it to compute the variance, skewness, and kurtosis of fluctuations of baryon number, and compare to measurements of proton number fluctuations in central Au-Au collisions as measured by the STAR Collaboration in a beam energy scan at the Relativistic Heavy-Ion Collider. The crossover equation of state can reproduce the data if the fluctuations are frozen out at temperatures well below than the average chemical freeze-out.
© SIF, Springer-Verlag Berlin Heidelberg, 2016
