Precision measurement of the neutrino mixing parameters and the determination of mass hierarchy are the primary goals of the present and upcoming neutrino experiments. In this work, we study the sensitivity of T2K,NO$ u$A and LBNE experiments to disc
over leptonic CP violation and the determination of neutrino mass hierarchy. We obtain the correlation between the CP violating phase $delta_{CP}$ and the mixing angles $theta_{13}$, $theta_{23}$ and the sensitivity to determine the octant of atmospheric mixing angle $theta_{23}$. The entire analysis is done for a total 10 years (5$ u$+ 5$bar u$) of running of T2K, NO$ u$A and LBNE experiments. Furthermore, we also consider the impact of cross section uncertainties on the CP violation sensitivity of LBNE experiment.
With the recent measurement of reactor mixing angle $theta_{13}$ the knowledge of neutrino oscillation parameters that describe PMNS matrix has improved significantly except the CP violating phase $delta_{CP}$. The other unknown parameters in neutrin
o oscillation studies are mass hierarchy and the octant of the atmospheric mixing angle $theta_{23}$. Many dedicated experiments are proposed to determine these parameters which may take at least 10 years from now to become operational. It is therefore very crucial to use the results from the existing experiments to see whether we can get even partial answers to these questions. In this paper we study the discovery potential of the ongoing NO$ u$A and T2K experiments as well as the forthcoming T2HK experiment in addressing these questions. In particular, we evaluate the sensitivity of NO$ u$A to determine neutrino mass hierarchy, octant degeneracy and to obtain CP violation phase after running for its scheduled period of 3 years in neutrino mode and 3 years in anti-neutrino mode. We then extend the analysis to understand the discovery potential if the experiments will run for (5$ u$+5$bar{ u}$) years and (7$ u$+3$bar{ u}$) years. We also show how the sensitivity improves when we combine the data from (3$ u$+3$bar{ u}$) years of NO$ u$A run with (3$ u$+2$bar{ u}$) years of T2K and (3$ u$+7$bar{ u}$) years of T2HK experiments. The CP violation sensitivity is marginal for T2K and NO$ u$A experiments even for ten years data taking of NO$ u$A. T2HK has a significance above 5$sigma$ for a fraction of two-fifth values of the $delta_{CP}$ space. We also find that $delta_{CP}$ can be determined to be better than $35^circ $, $21^circ $ and $9^circ $ for all values of $delta_{CP}$ for T2K, NO$ u$A and T2HK respectively.
The recent T2K, MINOS and Double Chooz oscillation data hint a relatively large $theta_{13}$, which can be accommodated by some general modification of the Tribimaximal/Bimaximal/Democratic mixing matrices. Using such matrices we analyze several Majo
rana mass matrices with texture one-zero and show whether they satisfy normal or inverted mass hierarchy and phenomenologically viable or not.
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.
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 con
straints 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 $Bto phi K_s$.
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 suppresse
d 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.
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-indu
ced 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.
The decay channels $B_d^0 to D^{*0} K^{*0}$ are investigated for extracting weak $CKM$ phase information. These channels are described by color-suppressed tree diagrams only and are free from penguin contributions. The branching ratios for these chan
nels are found to be $sim cal O $ $(10^{-5} - 10^{-6})$ which can be measured at the currently running $B$ factories. The method presented here may be well-suited to determine the phase $gamma$.
We study the effect of unparticle stuff on $B_s - bar{B}_s$ mixing and consider possible implications of it for the decaymodes $B_s to J/psi phi$ and $phi phi$. We find that due to the new contributions from the unparticles the $B_s - bar{B}_s$ mixin
g phase could be observable at the LHC along with the possible sizable CP asymmetry parameters $S_{psi phi(phi phi)}$ in $B_s to J/psi phi(phi phi)$ decay modes.
