Neutrinos are the fundamental particles, blind to all kind of interactions except the weak and gravitational. Hence, they can propagate very long distances without any deviation. This characteristic property can thus provide an ideal platform to investigate Planck suppressed physics through their long distance propagation. In this work, we intend to investigate CPT violation through Lorentz invariance violation (LIV) in the long-baseline accelerator based neutrino experiments. Considering the simplest four-dimensional Lorentz violating parameters, for the first time, we obtain the sensitivity limits on the LIV parameters from the currently running long-baseline experiments T2K and $$\hbox {NO}\nu \hbox {A}$$NOνA. In addition to this, we show their effects on mass hierarchy and CP violation sensitivities by considering $$\hbox {NO}\nu \hbox {A}$$NOνA as a case study. We find that the sensitivity limits on LIV parameters obtained from T2K are much weaker than that of $$\hbox {NO}\nu \hbox {A}$$NOνA and the synergy of T2K and $$\hbox {NO}\nu \hbox {A}$$NOνA can improve these sensitivities. All these limits are slightly weaker ($$2 \sigma $$2σ level) compared to the values extracted from Super-Kamiokande experiment with atmospheric neutrinos. Moreover, we observe that the mass hierarchy and CPV sensitivities are either enhanced or deteriorated significantly in the presence of LIV as these sensitivities crucially depend on the new CP-violating phases. We also present the correlation between $$\sin ^2 \theta _{23}$$sin2θ23 and the LIV parameter $$|a_{\alpha \beta }|$$|aαβ|, as well as $$\delta _{CP}$$δCP and $$|a_{\alpha \beta }|$$|aαβ|.

In the current epoch of neutrino physics, many experiments are aiming for precision measurements of oscillation parameters. Thus, various new physics scenarios which alter the neutrino oscillation probabilities in matter deserve careful investigation. In this context, we study the effect of a vector leptoquark which induces non-standard neutrino interactions (NSI) that modify the oscillation probabilities of neutrinos in matter. We show that such interactions provide a relatively large value of NSI parameter $$\varepsilon _{e \mu }$$ ε e μ . Considering this NSI parameter, we successfully explain the recent discrepancy between the observed $$\delta _{CP}$$ δ CP results of T2K and NOvA.

In this paper, we study the hierarchy sensitivity of Protvino to ORCA (P2O) experiment in three flavour scenario as well as its sensitivity to non-standard interactions (NSI) in neutrino propagation. Because of the largest possible baseline length of 2595 km, P2O is expected to have strong sensitivity towards neutrino mass hierarchy and NSI parameters. In our study, we show that even though the number of appearance channel events for the minimal configuration of P2O are higher compared to DUNE, still the hierarchy sensitivity of P2O is less than DUNE because of large background events. Our results show that for a background reduction factor of 0.46 and appearance channel background systematic normalization error of 4%, the hierarchy sensitivity of P2O becomes equivalent of DUNE for δCP = 195°. We call this configuration of P2O as optimized P2O. Regarding the study of NSI, we find that, for ϵeμ (ϵeτ) sensitivity of DUNE is similar (better) as compared to optimized P2O when both ϵeμ and ϵeτ are included in the analysis. Our results show that in presence of NSI, the change of hierarchy sensitivity with respect to standard three flavor scenario, is higher in P2O as compared to DUNE. Further, hierarchy sensitivity in presence of NSI is lower (higher) than sensitivity in the standard three flavour scenario for δCP = 270°(90°). It is important to note that hierarchy sensitivity of optimized P2O does not get significantly better than DUNE for the current favourable values of δCP which is 180° < δCP< 360° as obtained by the global analysis in both standard three flavour and in presence of NSI.

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Recent ν e appearance data from the Mini Booster Neutrino Experiment (MiniBooNE) are in support of the excess of events reported by the Liquid Scintillator Neutrino Detector (LSND), which provides an indirect hint for the existence of eV-scale sterile neutrino. As these sterile neutrinos can mix with the standard active neutrinos, in this paper, we explore the effect of such active-sterile mixing on the determination of various oscillation parameters by the currently running long-baseline neutrino experiments. We find that the existence of sterile neutrino can lead to new kind of degeneracies among these parameters which would deteriorate the mass hierarchy sensitivity of NOνA experiment. We also find that addition of data from T2K experiment helps in resolution of degeneracies.

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Recent νe appearance data from the Mini Booster Neutrino Experiment support the excess of events reported by the Liquid Scintillator Neutrino Detector, which provides an indirect hint of the existence of eV-scale sterile neutrinos. As these sterile neutrinos can mix with the standard active neutrinos, in this paper we explore the effect of such active–sterile mixing on the determination of various oscillation parameters by the currently running long-baseline neutrino experiments T2K and NOνA. We find that the existence of sterile neutrinos can lead to new kinds of degeneracies among these parameters which would substantially deteriorate the mass hierarchy sensitivity of the NOνA experiment. We further notice that the inclusion of data from the T2K experiment helps in resolving the degeneracies. The impact of new CP-violating phases δ14 and δ34 on the maximal CP violation exclusion sensitivity for the NOνA experiment has also been illustrated. Finally, we discuss the implication of such light sterile neutrinos on neutrinoless double-beta decay processes in line with recent experimental results, as well as on the sensitivity reach of future experiments.

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