Evidence for a First Order, Finite Temperature Phase Transition in 8 Flavor QCD

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As part of our ongoing investigations of QCD with many flavors of quarks, here we report on studies of the finite temperature phase transition for eight-flavor QCD with the DBW2 gauge action and na\"ive staggered fermions.

• We find a clear first order phase transition between the chirally asymmetric phase at zero temperature and the chirally symmetric phase at finite temperature, signaled by a two-state signal for $\langle\bar{\psi}\psi\rangle$ at a non-zero temperature.
• We see this signal at a gauge coupling of $\beta=0.54$, where, to set the scale, the zero temperature value for $f_\pi$, in the chiral limit, is 0.06661(92).
• This strong, first-order signal is seen for two different values of the quark mass, $m_q=0.007$ and 0.0195, at $N_\tau=8$ and 6 respectively.