# The 34th International Symposium on Lattice Field Theory (Lattice 2016)

Jul 24 – 30, 2016
Highfield Campus, University of Southampton
Europe/London timezone

## Roberge-Weiss transition in Nf=2 QCD with staggered fermions and Nt=6

Jul 25, 2016, 5:05 PM
20m
Building 32 Room 1015 (Highfield Campus, University of Southampton)

### Building 32 Room 1015

#### Highfield Campus, University of Southampton

Talk Nonzero Temperature and Density

### Speaker

Mr Alessandro Sciarra (Goethe Universität)

### Description

﻿The QCD phase diagram at imaginary chemical potential exhibits a rich structure and studying it can constrain the phase diagram at real values of the chemical potential. Moreover, at imaginary chemical potential standard numeric techniques based on importance sampling can be applied, since no sign problem is present. In the last decade, a first understanding of the QCD phase diagram at imaginary chemical potential has been developed, but it is so far based on investigations on coarse lattices ($N_t=4,\;a=0.3$ fm). Considering the $N_f=2$ case, at the Roberge-Weiss critical value of the imaginary chemical potential, the chiral/deconfinement transition is first order for light/heavy quark masses and second order for intermediate values of the mass: there are then two tricritical masses, whose position strongly depends on the lattice spacing and on the discretisation. On $N_t=4$, we have the chiral $m_{\pi}^{\mbox{tric.}}\simeq400$ MeV with unimproved staggered fermions and $m_{\pi}^{\mbox{tric.}}\simeq900$ MeV with unimproved pure Wilson fermions. Employing finite size scaling we investigate the change of this tricritical point between $N_t=4$ and $N_t=6$ as well as between Wilson and staggered discretisations.

### Primary author

Mr Alessandro Sciarra (Goethe Universität)

### Co-author

Prof. Owe Philipsen (Goethe Universität)

### Presentation materials

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