Towards the chiral phase transition in the Roberge-Weiss plane

Abstract

We discuss the interplay between chiral and center sector phase transitions that occur in QCD with an imaginary quark chemical potential $\mu =i(2n+1)\pi T/3$. Based on a finite size scaling analysis in (2+1)-flavor QCD using HISQ fermions with a physical strange quark mass and a range of light quark masses, we show that the endpoint of the line of first-order Roberge-Weiss (RW) transitions between center sectors is second order for light quark masses $m_l\ge m_s/320$, and that it belongs to the $3$-d, $Z(2)$ universality class. The operator for the chiral condensate behaves like an energy-like operator in an effective spin model for the RW phase transition. As a consequence, for any non-zero value of the quark mass, the chiral condensate will have an infinite slope at the RW phase transition temperature, $T_{RW}$. Its fluctuation, the disconnected chiral susceptibility, behaves like the specific heat in $Z(2)$ symmetric models and diverges in the infinite volume limit at the RW phase transition temperature $T_{RW}$ for any non-zero value of the light quark masses. Our analysis suggests the critical temperatures for the RW phase transition and the chiral phase transition coincide in the RW plane. On lattices with temporal extent $N_{\tau }=4$, we find in the chiral limit $T_{\chi }=T_{RW}=195(1)$MeV.

17 pages

References in corpus (12)

• The QCD Equation of State with almost Physical Quark Masses
• Highly Improved Staggered Quarks on the Lattice, with Applications to Charm Physics
• The QCD Equation of State to $\mathcal{O}({\mu }_B^6)$ from Lattice QCD
• On the order of the QCD chiral phase transition for different numbers of quark flavours
• The chiral phase transition in two-flavor QCD from imaginary chemical potential
• Second order cumulants of conserved charge fluctuations revisited I. Vanishing chemical potentials
• The Roberge-Weiss endpoint in N_f = 2 QCD
• The Chiral Phase Transition in three-flavor QCD from Lattice QCD
• Critical endpoint of finite temperature phase transition for three flavor QCD
• Critical point phase transition for finite temperature 3-flavor QCD with non-perturbatively O($a$) improved Wilson fermions at $N_{\mathrm{t}}=10$
• Net-baryon number fluctuations
• Conserved charge fluctuations in the chiral limit

Cited by in corpus (5)

• SIMULATeQCD: A simple multi-GPU lattice code for QCD calculations
• Determination of Lee-Yang edge singularities in QCD by rational approximations
• Searching for the QCD critical point using Lee-Yang edge singularities
• Study of the effects of external imaginary electric field and chiral chemical potential on quark matter
• On the nature of the QCD chiral phase transition with imaginary chemical potential