YUKAWA-COUPLING CORRECTIONS TO SCALAR QUARK DECAYS

Heavy squark decays into top and charginos or neutralinos could be an unexpected source of top quarks at hadron colliders. A detailed treatm ent of these processes is necessary for a reliable calculation of both the top quark production cross-section and the standard top quark bra nching ratio in the MSSM. Along this line we compute the electroweak c orrections to the sbottom decays (b) over tilde(a) --> chi(i)(-) t wit hin the Yukawa coupling approximation. The calculation of these higher order contributions requires renormalization of both the bottom squar k mixing angle and of tan beta. This type of corrections gives the lea ding order electroweak effects at low and high tan beta. (C) 1998 Else vier Science B.V. All rights reserved.