We report the first investigation of the QCD transition temperature $T_c$ for two flavors of staggered quarks with unequal masses at lattice spacings of $1/4T.$ On changing the $u/d$ quark mass ratio in such a way that $m_{{\pi }^0}^2{/m}_{{\pi }^{\pm }}^2$ changes from 1 to 0.78, thus bracketing the physical value of this ratio, we find that $T_c$ remains unchanged in units of both $m_{\rho }$ and ${\Lambda }_{\overline{\mathrm{MS}}}.$

• Received 19 September 2002

DOI:https://doi.org/10.1103/PhysRevD.66.094510