Exploring the QCD phase diagram

Abstract

Lattice simulations employing reweighting and Taylor expansion techniques have predicted a (μ,T)-phase diagram according to general expectations, with an analytic quark-hadron crossover at μ=0 turning into a first order transition at some critical chemical potential μ_E. By contrast, recent simulations using imgainary μfollowed by analytic continuation obtained a critical structure in the {m_{u,d},m_s,T,μ} parameter space favouring the absence of a critical point and first order line. I review the evidence for the latter scenario, arguing that the various raw data are not inconsistent with each other. Rather, the discrepancy appears when attempting to extract continuum results from the coarse (N_t=4) lattices simulated so far, and can be explained by cut-off effects. New (as yet unpublished) data are presented, which for N_f=3 and on N_t=4 confirm the scenario without a critical point. Moreover, simulations on finer N_t=6 lattices show that even if there is a critical point, continuum extrapolation moves it to significantly larger values of μ_E than anticipated on coarse lattices.

10 pages, 7 figures, Invited talk at the workshop 'Critical point and onset of deconfinement', GSI Darmstadt, July 9-13 2007

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Cited by in corpus (5)

• Lepton asymmetry and the cosmic QCD transition
• The Phase Diagram of Strongly-Interacting Matter
• Spontaneous magnetization in QCD and non-Fermi-liquid effects
• Chemical potentials of light hadrons and quarks from yield ratios of negative to positive particles in high energy $pp$ collisions
• Recent Result in QCD Thermodynamics from the Lattice