Speaker
Dr
Prasad Hegde
(Central China Normal University)
Description
Hydrodynamic models of heavy-ion collisions have increasingly begun to rely on lattice results for the Equation of State[1]. While the lattice has the advantage of being a first-principles approach to QCD, the notorious sign problem prevents a direct determination of the equation of state and other thermodynamic observables at finite baryon chemical potential $\mu_B$.
In our talk, we will present results from a high-statistics calculation of all the Taylor coefficients upto sixth order in a $(\mu_B,\mu_Q,\mu_S)$-expansion of the pressure. Our calculation allows us to extrapolate, for the first time, the equation of state on the freezeout curve upto $\mathcal{O}(\mu_B^4)$ while our sixth-order results show that the truncation error is not more than a few % upto $\mu_B/T\sim1.5$. Thus our equation of state should be useful in describing both the LHC results as well as results from RHIC beam energy scan down to $\sim$20 GeV. We will also use our results to construct the isentropic equation of state for strangeness-neutral systems.
Our lattice QCD calculations make use of the gauge ensembles generated using the HISQ action[2,3]. Our lattice sizes range from $6\times24^3$ to $12\times48^3$. The pion mass ($\sim$160 MeV) is nearly equal to its physical value while the strange quark mass has been set to exactly its physical value.
**References**
[1] See for e.g. C. Gale, S. Jeon and B. Schenke, Int. J. Mod. Phys. **A28**, 1340011 (2013); C. Shen, U. Heinz, P. Huovinen and H. Song, Phys. Rev. **C82**, 054904 (2010).
[2] A. Bazavov *et al.* [HotQCD Collaboration], Phys. Rev. **D86**, 035409 (2012).
[3] A. Bazavov, H.-T. Ding, P. Hegde, O. Kaczmarek, F. Karsch, E. Laermann, Y. Maezawa, S. Mukherjee, H. Ohno, P. Petreczky, C. Schmidt, S. Sharma, W. Soeldner and M. Wagner, Phys. Rev. Lett. **111**, 082301 (2013).
Author
Dr
Prasad Hegde
(Central China Normal University)
