Abstract
We calculate chiral susceptibilities in ($2+1$)-flavor QCD for different masses of the light quarks using the functional renormalization group (fRG) approach to first principles QCD. We follow the evolution of the chiral susceptibilities with decreasing masses as obtained from both the light-quark and the reduced quark condensate. The latter compares very well with recent results from the HotQCD Collaboration for pion masses ${m}_{\ensuremath{\pi}}\ensuremath{\gtrsim}100\text{ }\text{ }\mathrm{MeV}$. For smaller pion masses, fRG and lattice results are still consistent. In particular, the estimates for the chiral critical temperature are in very good agreement. We close by discussing different extrapolations to the chiral limit.
Highlights
The phase structure of QCD probed with heavy-ion collisions is well described by (2 þ 1)-flavor QCD
Assuming that the chiral phase transition is of second order in the limit of massless up and down quarks, it follows from universal scaling arguments [38] that the pion-mass scaling of the pseudocritical temperature defined as the position of the peak of the chiral susceptibility is controlled by the critical exponents of the underlying universality class
As already discussed in the previous section, the renormalized condensate only differs from the light-quark condensate by a temperature-independent shift
Summary
The phase structure of QCD probed with heavy-ion collisions is well described by (2 þ 1)-flavor QCD. For sufficiently small masses of the three quarks, one expects a finite mass range with a first-order chiral transition [22] This first-order regime may even extend to the limit of infinitely heavy strange quarks; see, e.g., Refs. Within a very recent lattice QCD study investigating pion masses in the range of 50 ≲ mπ ≲ 160 MeV with a physical strange quark mass, the scaling properties of the chiral susceptibility are found to be compatible with the 3D Oð4Þ universality class [33]. Assuming that the chiral phase transition is of second order in the limit of massless up and down quarks, it follows from universal scaling arguments [38] that the pion-mass scaling of the pseudocritical temperature defined as the position of the peak of the chiral susceptibility is controlled by the critical exponents of the underlying universality class.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.