Speaker
Description
Determining the order of the QCD chiral transition in the massless limit remains an important open problem in finite-temperature QCD. The critical behavior near this transition is also closely related to the strength of anomalous (U(1)_A) breaking. Möbius domain-wall fermions provide good control over chiral symmetry at finite cutoff and the correct axial-anomaly structure in the continuum limit, making them particularly suitable for studying these questions.
We present results from ((2+1))-flavor QCD calculations with Möbius domain-wall fermions and the dislocation suppressing determinant ratio (DSDR) at (N_\tau=8). We consider two light-quark masses corresponding to pion masses of approximately (110) and (80\,\mathrm{MeV}), with several temperatures across the transition region. We study the temperature and quark-mass dependence of the light-quark condensate and chiral susceptibilities and test their consistency with (O(4)) critical scaling at finite lattice spacing. We also discuss the effects of the finite fifth-dimensional extent and the associated residual chiral symmetry breaking on these observables.
We further investigate anomalous (U(1)A) breaking through the difference of the iso-vector pseudoscalar and scalar susceptibilities, (\chi\pi-\chi_\delta), over the full temperature range covered by our calculations and study its dependence on the light-quark mass. This provides complementary information on the strength of anomalous (U(1)_A) breaking across the chiral transition and its behavior as the light-quark mass is reduced.