TESTING TIME-REVERSAL INVARIANCE IN EXCLUSIVE SEMILEPTONIC B-MESON DECAYS

We demonstrate that polarization measurements in exclusive semileptoni c B decays are powerful tools for unraveling non-standard model source s of T-violation. Measurements of the transverse polarization of the t au lepton in the B --> D tau<(nu)over bar> and B --> Dtau<(nu)over ba r> decays probe separately effective scalar and pseudoscalar CP-violat ing four-Fermi interactions, whereas the D polarization in the B --> Dl<(nu)over bar> (l = e, mu) decay is sensitive to an effective right -handed quark current interaction. Two T-odd polarization structures e xist involving the D polarization and they can be isolated and studie d separately. An estimate of these T-odd effects is also given in the context of supersymmetric theories. (C) 1997 Elsevier Science B.V.