Search

This paper investigates the capability of long-baseline experiments, which are making use of neutrinos that are coming from Japan Proton Accelerator Research Complex, in establishing the unitarity of active-neutrino mixing by ruling out the nonunitary mixing scheme as a function of true values of CP-violating phase δCP. It is found that T2HK can establish the unitarity of active neutrino mixing at above 2σ C.L. irrespective of neutrino mass hierarchy and the true value of δCP, if the nonunitary (NU) parameter α21 is of the order of 10-2. Further, this paper also discusses the bound on the NU parameter in the 21 sector and the sensitivity limit of these experiments in determining the NU parameter. It is found that the bounds on (α21/2) are 0.028, 0.0026, 0.005 at 2σ C.L., respectively, for T2K, T2HK, and T2HKK. Moreover, it is also found that the sensitivity limit of T2HK on NU parameter is far better than that of both T2HKK and T2K. [ABSTRACT FROM AUTHOR]

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 δCP 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 ϵμeμe=0.01. [ABSTRACT FROM AUTHOR]

Nonstandard neutrino interactions (NSIs), the subleading effects in the flavor transitions of neutrinos, play a crucial role in the determination of the various unknowns in neutrino oscillations, such as neutrino mass hierarchy, the Dirac CP violating phase, and the octant of the atmospheric mixing angle. In this work, we focus on the possible implications of lepton flavor violating (LFV) NSIs, which generally affect the neutrino propagation, on the determination of these unknown oscillation parameters. We study the effect of these NSIs on the physics potential of the currently running and upcoming long-baseline experiments, i.e., T2K, NOνA, and DUNE. We also check the allowed oscillation parameter space in the presence of LFV NSIs. [ABSTRACT FROM AUTHOR]