Frankfurt 2014 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 20: Schwerionenkollisionen und QCD Phasen

HK 20.8: Vortrag

Dienstag, 18. März 2014, 15:45–16:00, HZ 7

The Binder cumulant in O(N)-models — •Paul Springer and Bertram Klein — Physik Department, Technische Universität München, 85747 Garching

The phase structure of QCD is a much discussed topic in particle physics. In the context of this discussion we need precise knowledge about the nature of the chiral phase transition. A powerful tool to investigate it are lattice simulations. They are, however, still restricted to relatively large quark masses, far from the chiral limit, and to small volumes, which could affect the critical behavior. These two facts complicate the scaling analysis of lattice QCD results.

In the chiral limit, a continuous phase transition is expected in two-flavor QCD. Since continuous phase transitions are controlled by the long range fluctuations, only the dimensionality and symmetries dictate the universal behavior near the critical point. Therefore, more simple systems from the same universality class can be investigated in order to describe scaling behavior which is expected in lattice QCD.

Because the long range fluctuations play a prominent role at continuous phase transitions, it is self-evident that it is useful to investigate the behavior of higher-order critical fluctuations at the transition point. For this purpose the Binder cumulants seem to be very well suited.

We analyze the fourth-order Binder cumulant in 3-dimensional O(2)- and O(4)-models in finite volumes using non-perturbative Renormalization Group methods. This approach allows us to gain explicit insight into the behavior of the critical fluctuations and provides a tool which assists in analysis of lattice QCD data.