BOUNDS ON SCALAR LEPTOQUARK MASSES FROM S,T,U PARAMETERS IN THE MINIMAL 4-COLOR QUARK-LEPTON SYMMETRY MODEL

The contributions into radiative correction parameters S,T,U from the scalar leptoquarks are calculated in the minimal gauge model with the four-color quark-lepton symmetry. It is shown that the contributions i nto T and U from the scalar leptoquark doublets are not positive defin ite. Using the current experimental data on S,T,U the bounds on the sc aler leptoquark masses are obtained. In particular, the existence of t he relatively light scalar leptoquark with electric charge 2/3 is show n to be compatible with the current experimental data on S,T,U. (C) 19 98 Published by Elsevier Science B.V. All rights reserved.