Speaker
Description
It has been argued in the literature that an effective restoration of the $U(1)_A$ symmetry can be probed by examining the degeneracy of flavour non-singlet pseudoscalar and scalar correlation functions. In this talk, I will present a method to investigate the onset of such degeneracies using correlators computed on anisotropic lattice ensembles generated by the FASTSUM collaboration with unphysical pion masses and $N_f=2+1$ flavours of sea quarks. As a first validation step, the method is applied to the vector and axial–vector channels, which are sensitive to the restoration of $SU(2)_L\times SU(2)_R$ chiral symmetry. The resulting pseudo-critical temperature is in agreement with that obtained from the renormalised chiral condensate on the same ensambles. Applying the method with scalar and pseudoscalar correlators we observe indications of effective $U(1)_A$ symmetry restoration in the temperature range $T_c < T_{U(1)_A} < 2T_c$.