The Higgs mass in the MSSM infrared fixed point scenario

In the infrared fixed point scenario of the minimal supersymmetric model (MSSM), the top-quark mass and other physical quantities of the low-energy theory are insensitive to the values of the parameters of the theory at some high energy scale. In this framework we evaluate the light CP-even Higgs mass, $m_h$, taking into account some important effects that had not been previously considered. The most notable of these is the supersymmetric correction to the relation between the running and the physical top-quark masses, which lowers the value of $\tan\beta$. As a result, the predicted value of $m_h$ is significantly lower than in previous evaluations. Assuming a supersymmetric threshold $M_S\leq 1$ TeV, we find an absolute upper bound of $m_h\le 97\pm 2$ GeV; the most plausible value of $m_h$ lies somewhat below the upper bound. This places the Higgs boson well within the reach of the LEP-2 Higgs search.