Showing papers by "Amitava Raychaudhuri published in 1994"

Rare decay H+-->W+ gamma in the minimal supersymmetric standard model.

Abstract: The amplitude for the one-loop-induced decay [ital H][sup +][r arrow][ital W][sup +][gamma] is calculated in the 't Hooft--Feynman gauge in the minimal supersymmetric standard model concentrating on the scalar sector only. It is shown that Feynman graphs with gauge bosons, physical and unphysical scalars, and Faddeev-Popov ghosts in the loops undergo large cancellations to contribute negligibly to the final amplitude. The dominant contribution comes from graphs with internal [ital t] and [ital b] quarks. A numerical evaluation shows that if the charged Higgs boson is lighter than the [ital t] quark, then the branching ratio for this process can be as large as [similar to]7[times]10[sup [minus]5]. For a wide range of parameters, this could remain well within the range of detect- ability at the CERN LHC and SSC.

Light gluinos and precision tests at the CERN e+e- collider LEP.

Abstract: A slight mismatch between the low and high energy [alpha][sub [ital s]] measurements has fueled speculation in recent times on the existence of light gluinos---a scenario not yet ruled out by direct experimental searches. We study the impact of light virtual gluinos ([similar to]3 GeV) on some electroweak observables measured at the CERN [ital e][sup +][ital e[minus]] collider LEP 1 with unprecedented precision. We conclude that squark masses in the range 50--60 GeV are disfavored by the present data with the above choice of gluino mass.