Finite size and cut-off effects on the Roberge-Weiss transition in $N_\text{f}=2$ QCD with Staggered fermions

Understand

In the absence of a genuine solution to the sign problem, lattice studies at imaginary quark chemical potential are an important tool to constrain the QCD phase diagram.

• We calculate the values of the tricritical quark masses in the Roberge-Weiss plane, $\mu=\imath\pi T/3$, which separate mass regions with chiral and deconfinement phase transitions from the intermediate region, for QCD with $N_\text{f}=2$ unimproved staggered quarks on $N_\tau=6$ lattices.
• A quantitative measure for the quality of finite size scaling plots is developed, which significantly reduces the subjective judgement required for fitting.
• We observe that larger aspect ratios are necessary to unambiguously determine the order of the transition than at $\mu=0$.