Semi-leptonic charm baryon decays in the relativistic spectator quark model

We calculate the exclusive semi-leptonic charm baryon decays of the lowest lying charm baryon states into the ground state strangeness baryons using the covariant spectator quark model approach. We present results on rates,q ²- andE _l -spectra as well as on the angular decay distribution in the cascade decay \(\Omega _c \to \Omega ( \to \Xi \pi ,\Lambda {\rm K})\) .     

Two-photon decays of mesons in a relativistic quark model

We present a relativistic calculation of two-photon decays for heavy and light mesons in the framework of the Salpeter equation for quark-antiquark states. The meson-photon-photon vertex is computed by reconstructing the Bethe-Salpeter vertex function and evaluating the four-dimensional Feynman diagram with off-shell quark amplitudes.The two-photon width for light and heavy quarkonia up to spin equal six are calculated with various parameter sets taken from the literature thus giving a complete overview on mesonic two-photon physics. We find that relativistic effects including the negative-energy components of the wave function are important for any two-photon width - even for heavy quarkonia - yielding a remarkable agreement with available data as well as predictions for future experiments.     

Exclusive semileptonic decays of heavy mesons

Exclusive semileptonic decays of heavy mesons provide interesting information on systems consisting of quarks of unequal mass. We express the formfactors of the hadronic current in terms of relativistic bound state wave functions for which we take the solutions of a relativistic harmonic oscillator potential. The wave function overlap is determined by the quark mass dependent longitudinal momentum distribution and differs from results based on non relativistic wave functions. The semileptonic widths and lepton spectra are calculated using in addition nearest pole dominance for the momentum transfer dependence of the formfactors. We compare our results with recent experimental data. The formfactor calculation also allows an estimate of special nonleptonic transitions. From the CLEO results on \(\bar B^0 \to \pi ^ + \pi ^ -\) and \(\bar B^0 \to D^{* + } + \pi ^ -\) we find for the corresponding Kobayashi-Maskawa matrix element ratio the limit |V _ub /V _cb |?0.3.     

CP violation in semi-leptonic decays of the top quark within MSSM

We calculate the CP violating effects in the top quark semi-leptonic three body decays induced by the supersymmetric CP-odd phase of the top squark trilinear soft breaking term . The light top squark mass is assumed to be close to the top quark mass, . The CP conserving phase is provided by the and cut. We find that the partial rate asymmetry is on the 0.1% level. In the most favorable parameter region the decay rate asymmetry can reach up to 0.55%. Received: 19 April 1999 / Published online: 16 November 1999     

Exclusive two-body weak decays of heavy mesons

Two-body weak decays of heavy mesons are studied using a simple non-relativistic model for the meson-quark-antiquark vertex. Numerical results are compared with experimental data where possible. The properties of the amplitudes calculated suggest that dynamical factors are important in determining the nature of these decays.     

Nonleptonic weak decays of bottom mesons

Based on the Kobayashi-Maskawa weak current model we investigate the properties of weak hadronic decays of the anticipated bottom mesons. Our main results concern twobody and quasitwobody decays of bottom mesons into pseudoscalar and vector mesons.