2008/07/05 by Ph. de Forcrand, O Philipsen
Physics and Astronomy · #Baryon #Critical point (mathematics) #Crossover #Deconfinement #High-Energy Particle Collisions Research #Lattice (music) #Lattice QCD #Mathematical physics #Monte Carlo method #Particle physics #Particle physics theoretical and experimental studies #Phase (matter) #Phase diagram #Physics #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum mechanics #Quark #hep-lat
paper · pdf · doi:10.1088/0954-3899/35/10/104098
4 pages, 6 figures, proceedings of Quark Matter 2008, Jaipur (India), Feb. 2008, to appear in J. Phys. G
arxiv created 2008/07/05 · openalex publication_date 2008/09/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The phase diagram of QCD, as a function of temperature T and quark chemical potential mu, may contain a critical point (muE,TE) whose non-perturbative nature makes it a natural object of lattice studies. However, the sign problem prevents the application of standard Monte Carlo techniques at non-zero baryon density. We have been pursuing an approach free of the sign problem, where the chemical potential is taken as imaginary and the results are Taylor-expanded in mu/T about mu=0, then analytically continued to real mu. Within this approach we have determined the sensitivity of the critical chemical potential muE to the quark mass, d(\μE)2/dmq|\μE=0. Our study indicates that the critical point moves to em smaller chemical potential as the quark mass em increases. This finding, contrary to common wisdom, implies that the deconfinement crossover, which takes place in QCD at mu=0 when the temperature is raised, will remain a crossover in the mu-region where our Taylor expansion can be trusted. If this result, obtained on a coarse lattice, is confirmed by simulations on finer lattices now in progress, then we predict that no em chiral critical point will be found for muB lesssim 500 MeV, unless the phase diagram contains additional transitions.