DELTA-F=2 EFFECTIVE LAGRANGIAN IN THEORIES WITH VECTOR-LIKE FERMIONS

in this work we analyze a new piece present in the Delta F = 2 effecti ve Lagrangian in models with extra vector-like quarks. This piece, whi ch was not taken into account previously, is required in order to pres erve gauge invariance once the unitarity of the CKM matrix is lost. We illustrate the effects of this new piece in both, CP conserving and C P violating processes. (C) 1998 Elsevier Science B.V. All irghts reser ved.