We study the polarization of the J/ψ meson of the B̄c → J/ψ μ ν̄μ decay process, followed by J/ψ → μμ, with the help of the heavy-quark spin symmetry formalism (HQSS) of Jenkins et al. [1] We adapt the ISGW wave function. Due to the clean signature of the decay mode, measurements of the polarization of the J/ψ meson can play a special role in extracting |Vcb|, the quark mixing-matrix element. We ...

We investigate the effect that a charged Higgs decay channel for the top quark has on the signature for top quark pair production at the Tevatron. The branching ratios for the various multijet and multilepton final states arising from tt production are obtained for a wide range of values for tanβ and the charged Higgs boson mass. In addition, the effect of the charged Higgs decay of the top qua...

Stop contributions to radiative corrections to Rb and the top quark decay are analysed over the relevant MSSM parameter space. One sees a 30% increase in the former along with a similar drop in the latter in going from the higgsino dominated to the mixed region. Consequently one can get a viable SUSY contribution to Rb within the constraint of the top quark data only in the mixed region, corres...

We calculate in the framework of two Higgs doublet models the differential decay rate for inclusive B̄ → τ ν̄ X transitions to order 1/m2b in the heavy quark expansion, for both polarized and unpolarized tau leptons. In contrast to the situation in the standard model, we find sizeable 1/m2b corrections. A systematic heavy quark expansion significantly reduces the theoretical uncertainties in the ...

By describing strong interactions between hadrons via a relativistic supermultiplet scheme and regarding weak interactions as a perturbation thereof, we derive expressions for nonleptonic weak decay amplitudes in terms of constituent quark masses and CKM angles, with no other parameters. Application of this method leads to ∆I = 1/2 dominance in some pseudoscalar meson decays if one scales down ...

Semileptonic decays of heavy baryons consisting of one heavy (Q = b, c) and two light (q = u, d, s) quarks are considered in the heavy-quark–light-diquark approximation. The relativistic quasipotential equation is used for obtaining masses and wave functions of both diquarks and baryons within the constituent quark model. The weak transition matrix elements are expressed through the overlap int...

We review the theory and phenomenology of heavy-quark symmetry, exclusive weak decays of B mesons, inclusive decay rates and lifetimes of b hadrons. To appear in the Second Edition of Heavy Flavours, edited by A.J. Buras and M. Lindner (World Scientific, Singapore) CERN-TH/97-24 February 1997 B DECAYS AND THE HEAVY-QUARK EXPANSION MATTHIAS NEUBERT Theory Division, CERN, CH-1211 Geneva 23, Switz...

We present complete one-loop radiative corrections to the decay rate of a top quark into a charged Higgs boson and a bottom quark, and for the decay of a charged Higgs boson into leptons. The results are discussed in the framework of the two Higgs boson extension of the Standard Model suggested by supersymmetry. The effect of electroweak corrections after exclusion of universal corrections ∆r i...

A method to extract B-physics parameters (b-quark mass and fB, fBs decay constants) from currently available lattice data is presented and tested. The approach is based on the idea of constructing appropriate ratios of heavy-light meson masses and decay constants, respectively, possessing a precisely known static limit, and evaluating them at various pairs of heavy quark masses around the charm...

We study the fragmentation of the b quark in top decay in NLO QCD, within the framework of perturbative fragmentation, which allows one to resum large logarithms ∼ log(m 2 t /m 2 b). We show the b-energy distribution, which we compare with the exact O(α S) result for a massive b quark. We use data from e + e − machines in order to describe the b-quark hadronization and make predictions for the ...