Explaining B to K pi anomaly with non-universal Z boson

We study the effect of non-universal $Z$ boson in the decay modes $B to K pi$. In the standard model these modes receive dominant contributions from $b to s$ QCD penguins. Therefore, in this limit one expects $S_{pi^0 K^0} approx sin 2 beta $, $A_{pi^0 K^0} approx 0$ and $A_{pi^0 K^-} approx A_{pi^+ K^-}$. The corrections due to the presence of small non-penguin contributions is found to yield $S_{pi^0 K^0} > sin 2 beta $ and $Delta A_{CP}(K pi) simeq 2.5 %$. However, the measured value of $S_{pi^0 K^0}$ is less than $ sin 2 beta $ and $Delta A_{CP}(K pi) simeq 15 %$. We show the model with a non-universal $Z$ boson can successfully explain these anomalies.

$B_s^0 - bar B_s^0$ mixing and $b to s $ transitions in isosinglet down quark model

The recent observation of the mass difference in $B_s$ system seems to be not in complete agreement with the corresponding standard model value. We consider the model with an extra vector like down quark to explain this discrepancy and obtain the constraints on the new physics parameters. Thereafter, we show that with these new constraints this model can successfully explain other observed deviations associated with $b to s$ transitions, namely, $B_s to psi phi$, $Bto K pi$ and $Bto phi K_s$.

Signature of new physics in B -> phi pi decay

We investigate the effect of an extra fourth quark generation and FCNC mediated $Z$ and $Z$ bosons on the rare decay mode $B^- to phi pi^-$. In the standard model, this mode receives only $b to d$ penguin contributions and therefore, highly suppressed with branching ratio $sim 5 times 10^{-9}$. This in turn makes this mode a very sensitive probe for new physics. We find that due to the above mentioned new physics contributions there is a significant enhancement in its branching ratio. Furthermore, the direct CP violation parameter which is identically zero in the SM is found to be quite significant. If this mode will be observed in the upcoming LHCb experiment, it will not only provide a clear signal of new physics but also can be used to constrain the new physics parameter space.

Probing the unparticle signal in $b to d $ penguin processes

We investigate the effect of unparticles in the pure $ b to d $ penguin processes $ B^0 to K^0 bar K^0$ and $B^{+,0} to phi pi^{+,0} $. Since these processes receive dominant contributions due to the {it top} quark in the loop, direct and mixing-induced CP asymmetry parameters in these processes are expected to be vanishingly small in the standard model. We find that due to the unparticle effect sizable nonzero CP violation could be possible in these channels.