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We investigate new physics models that can increase the lifetime differences in the $B_q$--$bar{B}_q$ systems ($q = d,s$) above their standard model values. If both $B_q$ as well as $bar{B}_q$ can decay to a final state through flavour dependent new physics interactions, the so-called Grossman bound may be evaded. As examples, we consider the scalar leptoquark model and $lambda$-type R-parity violating supersymmetry. We find that models with a scalar leptoquark can enhance $DeltaGamma_s/Gamma_s$ all the way up to its experimental upper bound and $DeltaGamma_d/Gamma_d$ to as much as $sim 2.5%$, at the same time allowing the CP violating phase $beta_s$ to vary between $- 45^circ$ and $20^circ$. R-parity violating supersymmetry models cannot enhance the lifetime differences significantly, but can enhance the value of $beta_s$ up to $sim pm 20^circ$. This may bring the values of $DeltaGamma_q/Gamma_q$ as well as $beta_s$ within the measurement capabilities of $B$ factories and LHCb. We also obtain bounds on combinations of these new physics couplings, and predict enhanced branching ratios of $B_{s/d} to tau^+ tau^-$.
We study $B_d$ and $B_s$ mixing in unquenched lattice QCD employing the MILC collaboration gauge configurations that include u, d, and s sea quarks based on the improved staggered quark (AsqTad) action and a highly improved gluon action. We implement
This article summarizes recent developments in $Bto D^{(ast)}tau u$ decays. We explain how to extract the tau leptons production properties from the kinematics of its decay products. The focus is on hadronic tau decays, which are most sensitive to th
We review the two and three-body baryonic $B$ decays with the dibaryon (${bf Bbar B}$) as the final states. Accordingly, we summarize the experimental data of the branching fractions, angular asymmetries, and $CP$ asymmetries. In the approach of pert
B meson semileptonic decays are a crucial tool in our studies of the quark mixing parameters Vcb and Vub. The interplay between experimental and theoretical challenges to achieve precision in the determination of these fundamental parameters is discussed.