INTERNAL SELF-CONSISTENCY OF WEAK NEUTRAL CURRENT DATA AT LEP/SLC FAVORS PHYSICS BEYOND STANDARD MODEL

Abstract

The recent measurements of Rb=Γb/Γhad together with other experimentally independent measurements of weak neutral current observables at LEP/SLC, display excellent internal self-consistency if the top dependent [Formula: see text] vertex correction is ignored. Extending this consistency further, the possibility of ignoring even the propagator/oblique corrections is not ruled out. Being a clean top mass indicator within SM, free from Higgs and strong interaction uncertainty, a comparison of Rb with the directly measured top quark mass at Tevatron clearly strengthens the above view. To preserve the weak radiative corrections of SM origin, for which evidence exists from measurements at low energies, independent of LEP/SLC, the most natural choice would be to invoke new radiative corrections of opposite sign from physics beyond SM. We stress that an improved measurement of Rb at LEP/SLC together with the direct measurement of top quark mass at Tevatron will play a clean and decisive role in this direction.