Light gluinos and precision tests at the CERNe+e−collider LEP

A slight mismatch between the low and high energy ${\alpha }_s$ 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 (∼3 GeV) on some electroweak observables measured at the CERN $e^{+}{e}^{-}$ 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.