Related papers: Possibility of large lifetime differences in neutr…
In the standard model, CP asymmetries in the $B^\pm \to \pi^\pm K$ channels are about 2% based on perturbative calculation. Rescattering effects might enhance it to at most (20-25)%. We show that lepton-number-violating $\lambda'$ couplings…
We derive the upper bounds on certain products of R-parity- and lepton-flavor-violating couplings from $B \ra X_s {l_i}^+ {l_j}^-$ decays. These modes of B-meson decays can constrain the product combinations of the couplings with one or…
We consider a possibility that $R$-parity violating interactions of particles which do not involve the first generation have large (up to 1) coupling constants, $\Lambda$. Such couplings, if exist, could have a number of phenomenological…
The present status of the theoretical estimates of the difference between the widths of the neutral Bs-mesons and of the B-meson lifetime ratios is reviewed. In particular, the lattice results for the matrix elements of the relevant (delta…
Recent time-dependent CP asymmetry measurements in the $B_d \to J/\psi K_S$ channel by the BaBar and Belle Collaborations yield somewhat lower values of $\sin 2\beta$ compared to the one obtained from the standard model fit. If the…
Using the expansions of the heavy meson decay widths in the heavy quark mass and QCD sum rules for estimates of corresponding matrix elements,\, we calculate the $D^{\pm,o,s}$ and $B^{\pm,o,s}$ meson lifetimes. The results for D mesons are…
One possible probe to physics beyond the standard model is to look for scalar bilinears, which couple to two fermions of the standard model. We point out that the scalar bilinears allow new diagrams contributing to the neutrinoless double…
In recent years, significant experimental indications that point towards Lepton Flavour Universality violating effects in B-decays, involving $b \to c \tau \nu$ and $b \to s \ell^+ \ell^-$ have been accumulated. A possible New Physics…
We analyse present constraints on the SM parameter space and derive, in a model independent way, various bounds on New Physics contributions to $B_d^0$--$\bar B_d^0$ and $B_s^0$--$\bar B_s^0$ mixings. Our analyses include information on a…
We discuss the modes $B\to K^{(*)}\nu\bar\nu$ in the context of non-standard neutrino interactions that add incoherently to the SM rates. We consider two scenarios: an additional light neutrino; and neutrino lepton flavour violation. We…
Non-leptonic B_s decays into CP eigenstates that are caused by \bar b -> \bar cc\bar s quark-level transitions, such as B_s -> D_s^+D^-_s, J/psi eta^(') or J/psi phi, provide a powerful tool to search for ``new physics'', as the…
We derive the upper bounds on certain products of R-parity- and lepton-flavor-violating couplings from $B^\pm \to l^\pm \nu$ decays. These modes of B-meson decays can constrain the product combinations of the couplings with one or more…
Using the expansions of the heavy meson decay widths in the heavy quark mass and QCD sum rules for estimates of corresponding matrix elements,\, we calculate the $D^{\pm,o,s}$ decay widths and the $B^{\pm,o,s}$ lifetime differences. The…
The lifetime difference ($y_D=\Delta\Gamma_D/2\Gamma_D$) and mass difference ($x_D=\Delta m_D/\Gamma_D$) of neutral $D$ meson have been measured with $y_D=(0.80\pm 0.13)%$ and $x_D=(0.59 \pm 0.20)%$, respectively. Intriguingly, in contrast…
A global fit to quark flavour-physics data disfavours the Standard Model with 3.6 standard deviations and points towards new CP-violating physics in meson-antimeson mixing amplitudes. Tevatron data call for a new Bs-Bs-bar mixing phase and…
Motivated by the large like-sign dimuon charge asymmetry observed recently, whose explanation would require an enhanced decay rate of $B_s \to \tau^+ \tau^-$, we explore how large a branching ratio of this decay mode is allowed by the…
The recent measurements of $B_s^0 \to \mu\bar{\mu}$ decay candidates at the LHC consistent with the standard model rate, and the improving upper limits for $B_d^0 \to \mu\bar{\mu}$ can strongly constrain beyond the standard model physics.…
We give an update on the lifetime difference of $B_s$ mesons which accounts for recent lattice bag parameter results, and obtain $(\Delta\Gamma/\Gamma)_{B_s}=(9.3^{+3.4}_{-4.6})%$. We then review the current theoretical uncertainties and…
We study the effect of scalar leptoquarks in the lepton flavour violating $B$ meson decays induced by the flavour changing transitions $b \to q l_i^+ l_j^-$ with $q=s,d$. In the standard model these transitions are extremely rare as they…
A width difference of the order of 20\% has previously been predicted for the two mass eigenstates of the $B_s$ meson. The dominant contributor to the width difference is the $b\rightarrow c\bar c s$ transition, with final states common to…