Non-standard Neutrino Interactions Parameters Research Articles

Room for new physics in electron and neutrino scattering

ναe→νβe is studied to search new physics (NP). Both model dependent and independent approaches are used. Non-Standard Neutrino interactions (NSI) are invoked for the search of NP. The bounds on NSI parameter ɛ are found by using experimental data of LSND, LAMPF-E225, CHARM-II, BNL-COL and BNL-E734. The process is analyzed by using R parity violating Supersymmetry (⁄Rp SUSY) model which is proceeding through s-bosons exchange. Experimental data of LSND and LAMPF-E225 utilized for the identification of allowed region for non-universal SUSY parameters ∑jλ1j1. In the similar fashion, CHARM-II, BNL-COL and BNL-E734 data is exploited for the exploration of allowed and forbidden limits for ∑kλ21k and ∑jλ2j1. We also establish relationship between MI and SUSY coupling parameters.

Non universality of leptons as a source of new physics from non standard interactions of pseudoscalar mesons

The rare decays, K+→π+νν¯, B+→π+νν¯ and D+→π+νν¯, are investigated in the frame work of nonstandard neutrino interactions (NSI). It is claimed that NSI are arising due to non-universality of the leptons and bounds on NSI parameters ϵll′uL are determined. For this purpose, the branching ratios (Br) of these processes with in the Standard Model (SM) and beyond the SM are calculated by applying the non-universality of the leptons. The NSI in K+→π+νν¯ and B+→π+νν¯ proceed with u quark in the loop while other two with d quark in the loop. Very stringent 1 σ level constrains on non-standard parameters (ϵττuL and ϵτl′uL) are pointed out.

Constraining nonstandard interactions with coherent elastic neutrino-nucleus scattering at the European Spallation Source

The European Spallation Source (ESS), currently under construction in Sweden, will provide an intense pulsed neutrino flux allowing for high-statistics measurements of coherent elastic neutrino-nucleus scattering (CE{\nu}NS) with advanced nuclear recoil detectors. In this paper, we investigate in detail the possibility of constraining non-standard neutrino interactions (NSIs) through such precision CE{\nu}NS measurements at the ESS, considering the different proposed detection technologies, either alone or in combination. We first study the sensitivity to neutral-current NSI parameters that each detector can reach in 3 years of data taking. We then show that operating two detectors simultaneously can significantly improve the expected sensitivity on flavor-diagonal NSI parameters. Combining the results of two detectors turns out to be even more useful when two NSI parameters are assumed to be nonvanishing at a time. In this case, suitably chosen detector combinations can reduce the degeneracies between some pairs of NSI parameters to a small region of the parameter space.

Charged-current non-standard neutrino interactions at the LHC and HL-LHC* *Supported by the National Natural Science Foundation of China (11875157, 12147214), the Natural Science Foundation of the Liaoning Scientific Committee (LJKZ0978), and the Outstanding Research Cultivation Program of Liaoning Normal University (21GDL004).

A series of new physics scenarios predict the existence of the extra charged gauge boson , which can induce charged-current (CC) non-standard neutrino interactions (NSIs). The theoretical constraints on the simplified model and further on the CC NSI parameters from partial wave unitarity and decays are considered. The sensitivity of the process to the model at the LHC and high-luminosity (HL) LHC experiments is investigated by estimating the expected constraints on ( or μ) using a Monte-Carlo (MC) simulation. We find that the interference effect plays an important role, and the LHC can strongly constrain . Compared with those at the LHC with , the expected constraints at the LHC with can be strengthened to approximately one order of magnitude.

Vector leptoquark U_3 and CP violation at T2K, NOvA experiments

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 }. Considering this NSI parameter, we successfully explain the recent discrepancy between the observed delta _{CP} results of T2K and NOvA.

Strong Constraints on Neutrino Nonstandard Interactions from TeV-Scale ν_{μ} Disappearance at IceCube.

We report a search for nonstandard neutrino interactions (NSI) using eight years of TeV-scale atmospheric muon neutrino data from the IceCube Neutrino Observatory. By reconstructing incident energies and zenith angles for atmospheric neutrino events, this analysis presents unified confidence intervals for the NSI parameter ε_{μτ}. The best-fit value is consistent with no NSI at a p value of 25.2%. With a 90%confidence interval of -0.0041≤ε_{μτ}≤0.0031 along the real axis and similar strength in the complex plane, this result is the strongest constraint on any NSI parameter from any oscillation channel to date.

Constraining nonstandard neutrino interactions at electron colliders

The presence of nonstandard neutrino interactions (NSI) has a large effect on the precision measurements at next generation neutrino oscillation experiments. Other type of experiments are needed to constrain the NSI parameter space. We study the constraints on NSI with electrons from current and future $e^+e^-$ collider experiments including Belle II, STCF and CEPC. We find that Belle II and STCF will provide competitive and complementary bounds on electron-type NSI parameters compared to the current global analysis, and strong improvements for the constraints on tau-type NSI. In addition, CEPC alone will impose stringent constraints on the parameter space of NSI with electrons. We find that the degeneracy between the left-handed (vector) and right-handed (axial-vector) NSI parameters can be lifted by combining the data from three different running modes, and the allowed ranges for $|\epsilon_{ee}^{eL}|$ ($|\epsilon_{ee}^{eV}|$) and $|\epsilon_{ee}^{eR}|$ ($|\epsilon_{ee}^{eA}|$) can be constrained to be smaller than 0.002 at CEPC even if both of them are present.

New physics effects on quantum coherence in neutrino oscillations

Several measures of quantum correlations such as Leggett–Garg and Bell-type inequalities have been extensively studied in the context of neutrino oscillations. However, these analyses are performed under the assumption of standard model (SM) interactions of neutrinos. In this work, we study new physics effects on \(l_1\)-norm based measure of quantum coherence which quantifies the quantumness embedded in the system and is also intrinsically related to various measures of quantum correlations. Moreover, it is considered to be a resource theoretical tool which can be utilized in quantum algorithms and quantum channel discrimination. The new physics effects are incorporated in a model independent way by using the effective Lagrangian for the neutral current non-standard neutrino interactions (NSI). Bounds on the NSI parameters are extracted from a recent global analysis of oscillation experiments including COHERENT (coherent neutrino-nucleus scattering experiment) data. In the context of upcoming DUNE experimental setup, we find that the most favourable combination of LMA-Light sector of \(\theta _{12}\) (i.e., \(\theta _{12}< 45^{\circ }\)) with normal mass ordering decreases the coherence in the system in comparison to the SM prediction for all values of neutrino energy E and CP violating phase \(\delta \) (except in the narrow region around \(E \sim \) 2 GeV). On the other hand, a large enhancement in the value of coherence parameter in the entire \((E-\delta )\) plane is possible for the dark octant of \(\theta _{12}\) (\(\theta _{12}> 45^{\circ }\)) with inverted ordering. For almost all values of CP violating phase, the enhancement is more protuberant in the region around \(E \sim \) 4 GeV where maximum neutrino flux is expected in the DUNE experiment. Therefore for the normal mass ordering, the SM interaction provides favourable conditions for quantum information tasks while the NSI favours inverted ordering scenario for such tasks.

Improvements on perturbative oscillation formulas including non-standard neutrino interactions

We use perturbation theory to obtain neutrino oscillation probabilities, including the standard mass-mixing paradigm and non-standard neutrino interactions (NSI). The perturbation is made on the standard parameters and sin2(θ 13) and on the non-diagonal NSI parameters, but keeps diagonal NSI parameters non-perturbated. We perform the calculation for the channels ν μ → ν e and ν μ → ν μ . The resulting oscillation formulas are compact and present functional structure similar to the standard oscillation (SO) case. They apply to a wide range in the allowed NSI space of parameters and include the previous results from perturbative approaches as limit cases. Also, we use the compact formulas we found to explain the origin of the degeneracies in the neutrino probabilities in terms of the invariance of amplitude and phase of oscillations. Then we determine analytically the multiple sets of combinations of SO and NSI parameters that result in oscillation probabilities identical to the SO case.

Sensitivities of future solar neutrino observatories to nonstandard neutrino interactions

We study the matter effect caused by non-standard neutrino interactions (NSI) in the future solar neutrino experiments, DUNE, HK and MICA. The upcoming reactor experiment, JUNO is expected to provide the most precise measurements of solar neutrino oscillation parameters and is going to open up the era of sub-percent precision in the leptonic mixing sector of the Standard Model (SM). Considering JUNO can measure $\Delta m ^2 _{21}$ and $\theta_{12}$ by sub-percent precision and assuming SM as the null hypothesis, we study the possibility to constrain NSI parameters by the future solar neutrino experiments such as DUNE, HK and MICA. For this purpose, we study the effect of NSI on solar neutrino propagation in the Sun and Earth and explore the dependence of the day-night asymmetry on the NSI parameters. We also study the effect of NSI at the water Cerenkov detector on the simulated data for these experiments.

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

The muon decay-at-rest ($\mu$-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 $\mu$-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 $\mu$-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 $\mu$-e sector. For this parameter, we show that the $\mu$-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 $\mu$-DAR can measure $\delta_{\rm{CP}}$ is shown to be robust even in the presence of the considered NSIs. Finally, we show that the combination of $\mu$-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 $\varepsilon^{\mu e}_{\mu e}=0.01$.

Correlations and degeneracies among the NSI parameters with tunable beams at DUNE

The Deep Underground Neutrino Experiment (DUNE) is a leading experiment in neutrino physics which is presently under construction. DUNE aims to measure the yet unknown parameters in the three flavour oscillation scenario which includes discovery of leptonic CP violation, determination of the mass hierarchy and determination of the octant of $\theta_{23}$. Additionally, the ancillary goals of DUNE include probing the sub-dominant effects induced by new physics. A widely studied new physics scenario is that of nonstandard neutrino interactions (NSI) in propagation which impacts the oscillations of neutrinos. We consider some of the essential NSI parameters impacting the oscillation signals at DUNE and explore the space of NSI parameters as well as study their correlations among themselves and with the yet unknown CP violating phase, $\delta$ appearing in the standard paradigm. The experiment utilizes a wide band beam and provides us with a unique opportunity to utilize different beam tunes at DUNE. We demonstrate that combining information from different beam tunes (low energy, LE and medium energy, ME) available at DUNE impacts the ability to probe some of these parameters and leads to altering the allowed regions in two-dimensional space of parameters considered.

On the robustness of IceCube\u2019s bound on sterile neutrinos in the presence of non-standard interactions

The mixing parameters of sterile neutrino(s) preferred by the MiniBooNE and LNSD experiments are in strong tension with the exclusion limit from the IceCube experiment. Recently it has been claimed that by considering the non-standard neutrino interactions (NSI) in addition to the sterile neutrino, the IceCube’s limit can be relaxed and the tension can be reconciled; a baroque scenario as it has been called. We will show that this claim is just an artifact originating from the energy cuts of the chosen datasets. Contrary to the claim, by turning on the NSI and fixing the NSI parameters to the proposed values, not only the IceCube’s limit on sterile neutrino cannot be alleviated, but in fact the tension will be aggravated (or at least keeps its strength). To this aim, an analysis of the IceCube’s atmospheric neutrino data in the full energy range is crucial.

Challenges posed by non-standard neutrino interactions in the determination of δCP at DUNE

One of the primary objectives of the Deep Underground Neutrino Experiment (DUNE) is to discover the leptonic CP violation and to identify its source. In this context, we study the impact of non-standard neutrino interactions (NSIs) on observing the CP violation signal at DUNE. We explore the impact of various parameter degeneracies introduced by non-zero NSI and identify which of these can influence the CP violation sensitivity and CP precision of DUNE, by considering NSI both in data and in theory. In particular, we study how the CP sensitivity of DUNE is affected because of the intrinsic hierarchy degeneracy which occurs when the diagonal NSI parameter ϵee=−1 and δCP=±90°.

Accelerator and reactor complementarity in coherent neutrino-nucleus scattering

We study the complementarity between accelerator and reactor coherent elastic neutrino-nucleus elastic scattering (CE$\nu$NS) experiments for constraining new physics in the form of non-standard neutrino interactions (NSI). Firstly, considering just data from the recent observation by the COHERENT experiment, we explore interpretive degeneracies that emerge when activating either two or four unknown NSI parameters. Next, we demonstrate that simultaneous treatment of reactor and accelerator experiments, each employing at least two distinct target materials, can break a degeneracy between up and down flavor-diagonal NSI terms that survives analysis of neutrino oscillation experiments. Considering four flavor-diagonal ($ee/\mu\mu$) up and down-type NSI parameters, we find that all terms can be measured with high local precision (to a width as small as $\sim$5\% in Fermi units) by next-generation experiments, although discrete reflection ambiguities persist.

Non-standard interactions and neutrinos from dark matter annihilation in the Sun

We perform an analysis of the influence of non-standard neutrino interactions (NSI) on neutrino signal from dark matter annihilations in the Sun. Taking experimentally allowed benchmark values for the matter NSI parameters we show that the evolution of such neutrinos with energies at GeV scale can be considerably modified. We simulate propagation of neutrinos from the Sun to the Earth for realistic dark matter annihilation channels and find that the matter NSI can result in at most 30% correction to the signal rate of muon track events at neutrino telescopes. Still present experimental bounds on dark matter from these searches are robust in the presence of NSI within considerable part of their allowed parameter space. At the same time electron neutrino flux from dark matter annihilation in the Sun can be changed by a factor of few.

Sensitivities to charged-current nonstandard neutrino interactions at DUNE

We investigate the effects of charged-current (CC) nonstandard neutrino interactions (NSIs) at the source and at the detector in the simulated data for the planned Deep Underground Neutrino Experiment (DUNE). We neglect the neutral-current NSIs at the propagation because several solutions have already been proposed for resolving the degeneracies posed by neutral-current NSIs but no solutions exist for the degeneracies due to the CC NSIs. We study the effects of CC NSIs on the simultaneous measurements of and in DUNE. The analysis reveals that 3σ C.L. measurement of the correct octant of in the standard mixing scenario is spoiled if the CC NSIs are taken into account. Likewise, the CC NSIs can deteriorate the uncertainty of the measurement by a factor of two relative to that in the standard oscillation scenario. We also show that the source and the detector CC NSIs can induce a significant amount of fake CP-violation and the CP-conserving case can be excluded by more than 80% C.L. in the presence of fake CP-violation. We further find DUNE’s potential for constraining the relevant CC NSI parameters from the single parameter fits for both neutrino and antineutrino appearance and disappearance channels at both the near and far detectors. The results show that there could be improvements in the current bounds by at least one order of magnitude at DUNE’s near and far detectors, except for a few parameters which remain weaker at the far detector.

Non-standard interactions of solar neutrinos in dark matter experiments

We show that non-standard neutrino interactions (NSI) can be probed in future direct dark matter detection experiments through both elastic neutrino-electron scattering and coherent neutrino-nucleus scattering. We show NSI can increase the event rate due to solar neutrinos, with a sharp increase for lower nuclear recoil energy thresholds. We also identify an interference range of NSI parameters for which the rate is reduced by approximately 40%. Finally, we show that the “dark side” solution for the solar neutrino mixing angle may be discovered at forthcoming experiments.

Nonstandard neutrino interactions at DUNE, T2HK and T2HKK

We study the matter effect caused by nonstandard neutrino interactions (NSI) in the next generation long-baseline neutrino experiments, DUNE, T2HK and T2HKK. If multiple NSI parameters are nonzero, the potential of these experiments to detect CP violation, determine the mass hierarchy and constrain NSI is severely impaired by degeneracies between the NSI parameters and by the generalized mass hierarchy degeneracy. In particular, a cancellation between leading order terms in the appearance channels when ϵeτ = cot θ23ϵeμ, strongly affects the sensitivities to these two NSI parameters at T2HK and T2HKK. We also study the dependence of the sensitivities on the true CP phase δ and the true mass hierarchy, and find that overall DUNE has the best sensitivity to the magnitude of the NSI parameters, while T2HKK has the best sensitivity to CP violation whether or not there are NSI. Furthermore, for T2HKK a smaller off-axis angle for the Korean detector is better overall. We find that due to the structure of the leading order terms in the appearance channel probabilities, the NSI sensitivities in a given experiment are similar for both mass hierarchies, modulo the phase change δ → δ + 180°.

Neutrino physics with non-standard interactions at INO

Non-standard neutrino interactions (NSI) involved in neutrino propagation inside Earth matter could potentially alter atmospheric neutrino fluxes. In this work, we look at the impact of these NSI on the signal at the ICAL detector to be built at the India-based Neutrino Observatory (INO). We show how the sensitivity to the neutrino mass hierarchy of ICAL changes in the presence of NSI. The mass hierarchy sensitivity is shown to be rather sensitive to the NSI parameters $\epsilon_{e\mu}$ and $\epsilon_{e\tau}$, while the dependence on $\epsilon_{\mu\tau}$ and $\epsilon_{\tau\tau}$ is seen to be very mild, once the $\chi^2$ is marginalised over oscillation and NSI parameters. If the NSI are large enough, the event spectrum at ICAL is expected to be altered and this can be used to discover new physics. We calculate the lower limit on NSI parameters above which ICAL could discover NSI at a given C.L. from 10 years of data. If NSI were too small, the null signal at ICAL can constrain the NSI parameters. We give upper limits on the NSI parameters at any given C.L. that one is expected to put from 10 years of running of ICAL. Finally, we give C.L. contours in the NSI parameter space that is expected to be still allowed from 10 years of running of the experiment.