arXiv subjects

Soumya C.

Publications and source records attributed to Soumya C..

3 recordsLinked to original sources

arXiv2020

Probing muonic charged current nonstandard interactions at decay-at-rest facilities in conjunction with T2HK

The muon decay-at-rest ($μ$-DAR) facility provides us with an ideal platform to probe purely muonic charged-current nonstandard neutrino interactions (NSIs). We propose to probe this class of NSI effects using antineutrinos from a $μ$-DAR source in conjunction with neutrinos from the future Tokai to Kamioka superbeam experiment with megaton Hyper Kamiokande detector (T2HK). Even though muonic NSIs are absent in neutrino production at T2HK, we show that our proposed hybrid setup comprising $μ$-DAR and T2HK helps in alleviating the parameter degeneracies that can arise in data. Analytic considerations reveal that the oscillation probability is most sensitive to the NSI parameter in the $μ$-e sector. For this parameter, we show that the $μ$-DAR setup can improve on the existing bounds down to around 0.01, especially when the data are combined with neutrino data from T2HK experiment due to the lifting of parameter degeneracies. The high precision with which $μ$-DAR can measure $δ_{\rm{CP}}$ is shown to be robust even in the presence of the considered NSIs. Finally, we show that the combination of $μ$-DAR along with T2HK can also be used to put mild constraints on the NSI phase in the vicinity of the maximal CP-violating value for the chosen benchmark value of $\varepsilon^{μe}_{μe}=0.01$.

hep-ph↗

arXiv2017

Impact of lepton flavour universality violation on CP violation sensitivity of long baseline neutrino oscillation experiments

The observation of neutrino oscillation as well as the recent experimental result on lepton flavor universality (LFU) violation in $B$ meson decays are indications of new physics beyond the Standard Model. Many theoretical models, which are introduced in the literature as an extension of SM to explain these observed deviations in LFU, lead to new kind of interactions so-called non-standard interaction (NSI) between the elementary particles. In this paper, we consider a model with an additional $Z'$ boson (which is quite successful in explaining the observed LFU anomalies) and analyze its effect in the lepton flavour violating (LFV) $B_d\to τ^\pm e^\mp$ decay modes. From the present upper bound of the $B_d\to τ^\pm e^\mp$ branching ratio, we obtain the constraints on the new physics parameters, which are related to the corresponding NSI parameters in the neutrino sector by $SU(2)_L$ symmetry. These new parameters are expected to have potential implications in the neutrino oscillation studies and in this work we investigate the possibility of observing the effects of these interactions in the currently running and upcoming long-baseline experiments, i.e., NOvA and DUNE respectively.

hep-ph↗

arXiv2015

Predicting Leptonic CP phase by considering deviations in charged lepton and neutrino sectors

Recently, the reactor mixing angle $θ_{13}$ has been measured precisely by Daya Bay, RENO and T2K experiments with a moderately large value. However, the standard form of neutrino mixing patterns such as bimaximal, tri-bimaximal, golden ratio of types A and B, hexagonal etc., which are based on certain flavor symmetries, predict vanishing $θ_{13}$. Using the fact that the neutrino mixing matrix can be represented as $V_{\rm PMNS}=U_l^{\dagger} U_νP_ν$, where $U_l$ and $U_ν$ result from the diagonalization of the charged lepton and neutrino mass matrices and $P_ν$ is a diagonal matrix containing Majorana phases, we explore the possibility of accounting for the large reactor mixing angle by considering deviations both in the charged lepton and neutrino sector. In the charged lepton sector we consider the deviation as an additional rotation in the (12) and (13) planes, whereas in neutrino sector we consider deviations to various neutrino mixing patterns through (13) and (23) rotations. We find that with the inclusion of these deviations it is possible to accommodate the observed large reactor mixing angle $θ_{13}$, and one can also obtain limits on the CP violating Dirac phase $δ_{CP}$ and Jarlskog invariant $J_{CP}$ for most of the cases. We then explore whether our findings can be tested in the currently running NO$ν$A experiment with 3 years of data taking in neutrino mode followed by 3 years with anti-neutrino mode.

hep-ph↗