A 1993 Look at the Lower Bound on the Top Quark Mass from CP Violation

Abstract

We point out that the lower bound on $m_t$ from the CP violation parameter ${ϵ}_K$ has increased considerably. Using Wolfenstein parametrization of the CKM matrix we derive an analytic expression for this bound as a function of $\mid V_{cb}\mid ,\mid V_{ub}/V_{cb}\mid$ and the non-perturbative parameter $B_K$. For $B_K\le 0.80,\mid V_{cb}\mid \le 0.040$ and $\mid V_{ub}/V_{cb}\mid \le 0.10$ we find $m_t>130GeV$. However, for $B_K\le 0.70,\mid V_{cb}\mid \le 0.038$ and $\mid V_{ub}/V_{cb}\mid \le 0.08$ the bound is raised to $m_t>205GeV$. The lower bound on $m_t$ from $B^o-{\bar{B}}^o$ mixing is also reconsidered.

Comments: latex, 8p, 3 figs not included, MPI-Ph/93-52 and TUM-T31-45/93