Can the minimal supersymmetric standard model with light bottom squark and light gluino survive Z-peak constraints? -: art. no. 111802

In the framework of the minimal supersymmetric model we examine the Z-peak constraints on the scenario of one light bottom squark (sbottom) (similar to2-5.5 GeV) and light gluino (similar to12-16 GeV) which has been successfully used to explain the excess of bottom quark production in hadron collisions. Such a scenario is found to be severely constrained by the CERN LEP Z-peak observables, especially by R-b, due to the large effect of gluino-sbottom loops. To account for the Rb data in this scenario, the other mass eigenstate of sbottom, i.e., the heavier one, must be lighter than 125 ( 195) GeV at 2sigma(3sigma) level, which, however, is disfavored by CERN LEP II experiments.