Neutrino non-standard interactions (NSI) with the first generation of standard model fermions can span a parameter space of large dimension and exhibit degeneracies that cannot be broken by a single class of experiment. Oscillation experiments, together with neutrino scattering experiments, can merge their observations into a highly informational dataset to combat this problem. We consider combining neutrino-electron and neutrino-nucleus scattering data from the Borexino and COHERENT experiments, including a projection for the upcoming coherent neutrino scattering measurement at the CENNS-10 liquid argon detector. We extend the reach of these data sets over the NSI parameter space with projections for neutrino scattering at a future multi-ton scale dark matter detector and future oscillation measurements from atmospheric neutrinos at the Deep Underground Neutrino Experiment (DUNE). In order to perform this global analysis, we adopt a novel approach using the copula method, utilized to combine posterior information from different experiments with a large, generalized set of NSI parameters. We find that the contributions from DUNE and a dark matter detector to the Borexino and COHERENT fits can improve constraints on the electron and quark NSI parameters by up to a factor of 2 to 3, even when relatively many NSI parameters are left free to vary in the analysis.
One of the main purposes of long-baseline neutrino experiments is to unambiguously measure the CP violating phase in the neutrino sector within the three neutrino oscillation picture. In the presence of physics beyond the Standard Model, the determination of the CP phase will be more difficult, due to the already known degeneracy problem. Working in the framework of non-standard interactions (NSI), we compute the appearance probabilities in an exact analytical formulation and analyze the region of parameters where the confusion problem is present. We also discuss some cases where the falsifica…
Direct Detection of Solar Neutrinos to Probe Tensions and Break Degeneracies in Long-Baseline Neutrino Experiments
Institut de Fìsica d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology（高等能源物理研究所，巴塞罗那科技研究院）；Instituto de Física Teórica IFT-UAM/CSIC（理论物理研究所 UAM/CSIC）；Tsung-Dao Lee Institute & School of Physics and Astronomy, Shanghai Jiao Tong University（上海交大李政道研究所与物理与天文学院）；Key Laboratory for Particle Astrophysics and Cosmology (MOE) & Shanghai Key Laboratory for Particle Physics and Cosmology, Shanghai Jiao Tong University（粒子天体物理与宇宙学教育部重点实验室及上海粒子物理与宇宙学重点实验室，上海交通大学）；Departamento de Física Teórica, Universidad Autónoma de Madrid（马德里自治大学理论物理系）；High Energy Theory Group, Physics Division, Brookhaven National Laboratory（布鲁克海文国家实验室物理部高能理论组）
The future long baseline experiments such as DUNE and T2HKK have promising prospects to determine the neutrino mass hierarchy and measuring standard $CP$ phase $δ$. However, presence of possible non-standard interactions of neutrinos with matter may intricate this picture and is the subject matter of the present work. We have studied the standard parameter degeneracies in presence of non-standard interactions(NSI) with DUNE and T2HKK experiments. We examine the mass hierarchy degeneracy assuming (i) all NSI parameters to be non-zero and (ii) one NSI parameter($ε_{eμ}$) and its corresponding $C…
We study parameter degeneracies that can occur in long-baseline neutrino appearance experiments due to nonstandard interactions (NSI) in neutrino propagation. For a single off-diagonal NSI parameter, and neutrino and antineutrino measurements at a single L/E, there exists a continuous four-fold degeneracy (related to the mass hierarchy and $θ_{23}$ octant) that renders the mass hierarchy, octant, and CP phase unknowable. Even with a combination of NO$ν$A and T2K data, which in principle can resolve the degeneracy, both NSI and the CP phase remain unconstrained because of experimental uncertain…
We present perturbative oscillation probabilities for electron and muon channels including non-standard interaction (NSI) effects. The perturbation was performed in standard parameters $Δm^2_{21}/Δm^2_{31}$ and $\sin^2{(θ_{13})}$ as in non-standard interaction couplings. Our goal is to match non-standard parameters with the standard ones. This leads to oscillation probabilities with NSI compact and with functional structure similar to the Standard Oscillation (SO) case. Such formalism allows us to recognize degeneracies between standard oscillation parameters and NSI parameters. In such scenar…
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 $θ_{23}$. 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 ne…
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 consider…
S. N. Bose National Centre for Basic Sciences（S.N. 玻色基础科学国家中心）；Theoretical Physics Division, Physical Research Laboratory（物理研究实验室理论物理部）；Division of Sciences, Krea University（克里亚大学理学院）
Neutrino oscillation in the matter could get affected by the sub-dominant, yet unknown, non-standard interactions. The upcoming long-baseline (LBL) neutrino experiments will be sensitive to these effects and can provide information on the unknown oscillation parameter values. In this article, we study the parameter degeneracies that can occur in DUNE, T2HK experiments, and a combination of both due to nonstandard interactions (NSI), arising simultaneously, from two different off-diagonal sectors, i.e., $e-μ$ and $e-τ$. We derive constraints on both the NSI sectors using the combined datasets o…
We discuss the impact of non-standard neutrino matter interactions (NSI) in propagation on the determination of CP phase in the context of the long baseline accelerator experiments such as Deep Underground Neutrino Experiment (DUNE). DUNE will mainly address the issue of CP violation in the leptonic sector. Here we study the role of NSI and its impact on the question of observing the CP violation signal at DUNE. We consider two scenarios of oscillation with three active neutrinos in absence and presence of NSI. We elucidate the importance of ruling out subdominant new physics effects introduce…
One of the primary objectives of Deep Underground Neutrino Experiment (DUNE) is to discover the leptonic CP violation and to identify it's 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 hierar…
We discuss a comprehensive way to study the parameter degeneracies in the form of a generalized degeneracy in the neutrino oscillation experiments. First we describe the various degeneracies by considering only neutrino run of the long baseline experiment (LBL), NO$ ν$A. Then we discuss the role of antineutrinos. Later, we present the combined role of T2K (LBL experiment) and ICAL@INO (atmospheric experiment) to resolve these degeneracies. We also discuss the affect of new physics like non-standards interactions (NSI) on the determination of neutrino mass hierarchy in DUNE.
We study the effect of non-standard interactions (NSIs) on the propagation of neutrinos through the Earth matter and how it affects the hierarchy sensitivity of the DUNE experiment. We emphasize on the special case when the diagonal NSI parameter $ε_{ee} = -1$, nullifying the standard matter effect. We show that, if in addition, CP violation is maximal then this gives rise to an exact intrinsic hierarchy degeneracy in the appearance channel, irrespective of the baseline and energy. Introduction of off-diagonal NSI parameter, $ε_{e τ}$, shifts the position of this degeneracy to a different $ε_{…
Coherent elastic neutrino-nucleus scattering consistent with the standard model has been observed by the COHERENT experiment. We study nonstandard neutrino interactions using the detected spectrum. For the case in which the nonstandard interactions (NSI) are induced by a vector mediator lighter than 50 MeV, we obtain constraints on the coupling of the mediator. For a heavier mediator, we find that degeneracies between the NSI parameters severely weaken the constraints. However, these degeneracies do not affect COHERENT constraints on the effective NSI parameters for matter propagation in the E…
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), while neglecting the neutral-current NSIs at the propagation due to the fact that several solutions have been proposed to resolve the degeneracies posed by neutral-current NSIs while no solution exists for the degeneracies due to the CC NSIs. We study the effects of CC NSIs on the simultaneous measurements of $θ_{23}$ and $δ_{CP}$ in DUNE. The analysis reveals that 3$σ$ C.L. measurement o…
To measure the last unknown $3ν$ oscillation parameter ($δ$), several long baseline neutrino experiments have been designed or proposed. Recently it has been shown that turning on neutral current Non-Standard Interactions (NSI) of neutrinos with matter can induce degeneracies that may even hinder the proposed state-of-the-art DUNE long baseline experiment from measuring the value of $δ$. We study how the result of the proposed MOMENT experiment with a baseline of 150 km and $200~{\rm MeV}<E_ν<600~{\rm MeV}$ can help to solve the degeneracy induced by NSI and determine the true value of $δ$.
我们对非标准中微子与电子的相互作用（NSI）进行了详细的分析，包括现有加速器和反应堆中的所有μ子和电子（反）中微子数据，以及四个LEP合作项目中的"中微子计数“数据（e- e+ -> nu nu gamma）。首先，我们执行一个参数，在一个时间的分析，显示如何改善大多数约束相对于以前的文献报道的结果。我们还提出了更强大的NSI参数允许在分析中自由变化的结果。我们显示了LEP数据与其他实验相结合的重要性，以消除全局分析中的简并性，约束保存风味的NSI参数，在90%和95 % C.L.，必须位于唯一允许的区域内。尽管有这些改进的限制，仍然有很大的改进空间，对即将进行的实验构成了巨大的挑战。
We study the sensitivity of current and future long-baseline neutrino oscillation experiments to the effects of dimension six operators affecting neutrino propagation through Earth, commonly referred to as Non-Standard Interactions (NSI). All relevant parameters entering the oscillation probabilities (standard and non-standard) are considered at once, in order to take into account possible cancellations and degeneracies between them. We find that the Deep Underground Neutrino Experiment will significantly improve over current constraints for most NSI parameters. Most notably, it will be able t…
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 $ε_{eτ} = \cotθ_{23} ε_{eμ}$, strongly affects the sensitivities to these two NSI parameters…
Neutrino non-standard interactions (NSI) with electrons are known to alter the picture of neutrino decoupling from the cosmic plasma. NSI modify both flavour oscillations through matter effects, and the annihilation and scattering between neutrinos and electrons and positrons in the thermal plasma. In view of the forthcoming cosmological observations, we perform a precision study of the impact of non-universal and flavour-changing NSI on the effective number of neutrinos, $N_{eff}$. We present the variation of $N_{eff}$ arising from the different NSI parameters and discuss the existing degener…
Current neutrino experiments measure the neutrino mixing parameters with an unprecedented accuracy. The upcoming generation of experiments will be sensitive to subdominant effects that can give information on the unknown neutrino parameters: the Dirac CP-violating phase, the mass ordering and the $θ_{23}$ octant. Determining the exact values of neutrino mass and mixing parameters is crucial to test neutrino models and flavor symmetries. In the first part of this review, we summarize the current status of neutrino oscillation parameters. We consider the most recent data from solar experiments a…
New physics beyond the Standard Model could appear at long baseline oscillation experiments as non-standard interactions (NSI) between neutrinos and matter. If so, determination of the CP-violating phase $δ_{13}$ is ambiguous due to interference with additional complex phases. I'll present my work using both numerical solutions and a perturbative approach to study oscillation probabilities in the presence of NSI. I'll show how the CP phase degeneracies are visualized on biprobability plots, and the extent to which the energy spectrum for a given baseline length can help resolve them. In partic…
We explore the role of matter effect in the evolution of neutrino oscillation parameters in the presence of lepton-flavor-conserving and lepton-flavor-violating neutral-current non-standard interactions (NSI) of the neutrino. We derive simple approximate analytical expressions showing the evolution/running of mass-mixing parameters in matter with energy in the presence of standard interactions (SI) and SI+NSI (considering both positive and negative values of real NSI parameters). We observe that only the NSI parameters in the (2,3) block, namely $\varepsilon_{μτ}$ and $(γ- β) \equiv (\varepsil…
We study the complementarity between accelerator and reactor coherent elastic neutrino-nucleus elastic scattering (CE$ν$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 d…
Non-standard interactions (NSI) between neutrinos and electrons can significantly modify the decoupling of neutrinos from the plasma. These interactions have two effects on the overall picture: (i) they alter neutrino oscillations though matter effects and (ii) they modify the scattering and annihilation processes involving neutrinos and electrons and positrons. We study the role of non-universal and flavour-changing NSI in the decoupling and how they impact the determination of the effective number of neutrinos, $N_{eff}$. We examine the degeneracies between NSI parameters and we compare the …
We examine the prospects of probing nonstandard interactions (NSI) of neutrinos in the e-tau sector with upcoming long-baseline nu_mu -> nu_e oscillation experiments. First conjectured decades ago, neutrino NSI remain of great interest, especially in light of the recent 8B solar neutrino measurements by SNO, Super-Kamiokande, and Borexino. We observe that the recent discovery of large theta_13 implies that long-baseline experiments have considerable NSI sensitivity, thanks to the interference of the standard and new physics conversion amplitudes. In particular, in some parts of NSI parameter s…
Oscillation-Independent Probes of Neutrino Non-Standard Interactions from Supernovae
San Francisco State University（旧金山州立大学）；University of California Berkeley（加州大学伯克利分校）；New York University（纽约大学）；High Energy Accelerator Research Organization (KEK)（高能加速器研究机构（KEK））；Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK)（高能加速器研究机构粒子与核研究研究所（IPNS，KEK））；Graduate University for Advanced Studies (SOKENDAI)（综合研究大学院大学（SOKENDAI））；The University of Tokyo（东京大学）
We discuss the analytical expression of the oscillation probabilities at low energy long baseline experiments, such as T2HK and T2HKK in the presence of nonstandard interactions (NSIs). We show that these experiments are advantageous to explore the NSI parameters ($ε_D$, $ε_N$), which were suggested to be nonvanishing to account for the discrepancy between the solar neutrino and KamLAND data. We also show that, when the NSI parameters are small, parameter degeneracy in the CP phase $δ$, $ε_D$ and $ε_N$ can be resolved by combining data of the T2HK and T2HKK experiments.
Complementarity Between Neutrino Neutral and Charged Current Events in the Search for New Physics
Colorado State University（科罗拉多州立大学）；National Centre for Nuclear Research（国家核研究中心）；Fermi National Accelerator Laboratory（费米国家加速器实验室）；Shanghai Jiao Tong University（上海交通大学）
In the presence of non-standard neutrino interactions (NSI), a degeneracy exists in neutrino oscillation data, which involves the flipping of the octant of the mixing angle ${θ_{12}}$ and the type of the neutrino mass ordering. In this article, we revisit the status of this degeneracy in the light of recent data on coherent elastic neutrino-nucleus scattering (CE$ν$NS) from the COHERENT experiment. For general relative couplings to up and down quarks, the degeneracy is disfavoured at the $2σ$ level by the latest data but remains at a higher confidence level. We investigate the requirements of …
The full physics potential of the next-generation Deep Underground Neutrino Experiment (DUNE) is still being explored. In particular, there have been some recent studies on the possibility of improving DUNE's neutrino energy reconstruction. The main motivation is that a better determination of the neutrino energy in an event-by-event basis will translate into an improved measurement of the Dirac $CP$ phase and other neutrino oscillation parameters. To further motivate studies and improvements on the neutrino energy reconstruction, we evaluate the impact of energy resolution at DUNE on an illus…
Moving a Detector to Probe New Neutrino Interactions: IWCD at Hyper-Kamiokande
High Energy Accelerator Research Organization (KEK)（高能加速器研究机构）；Graduate University for Advanced Studies (SOKENDAI)（高级研究大学）；The University of Tokyo（东京大学）
Diagnosing Unmodeled Neutrino Physics via DUNE and T2HK Complementarity
State Key Laboratory of Dark Matter Physics, Tsung-Dao Lee Institute & School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院）；Key Laboratory for Particle Astrophysics and Cosmology (MOE) & Shanghai Key Laboratory for Particle Physics and Cosmology, Shanghai Jiao Tong University（上海交通大学）；Tata Institute of Fundamental Research（塔塔基础研究所）
The low-energy threshold and the large detector size of Precision IceCube Next Generation Upgrade (PINGU) can make the study on neutrino oscillations with a planet-scale baseline possible. In this task, we consider the configuration that neutrinos are produced at CERN and detected in the PINGU detector, as a benchmark. We discuss its sensitivity of measuring the size of non-standard interactions (NSIs) in matter, which can be described by the parameter $ε_{αβ}$ ($α$ and $β$ are flavors of neutrinos). We find that the CERN-PINGU configuration improves $\tildeε_{μμ}\equivε_{μμ}-ε_{ττ}$ and $ε_{μ…
Non-standard interactions (NSI) between neutrinos and matter at long-baseline experiments could make determination of the CP-violating phase $δ_{13}$ ambiguous due to interference with additional complex phases. Such degeneracies are often studied in the context of specific experiments and a few parameter choices, leaving it unclear how to extract a general understanding of when two sets of parameters may be degenerate or how different types of experiments in principle combine to lift such a degeneracy. This work complements detailed simulations of individual experiments by showing how underly…
Crucial developments in neutrino physics would be the determination of the mass hierarchy (MH) and measurement of the CP phase in the leptonic sector. The patterns of the transition probabilities $P(ν_μ\rightarrow ν_τ)$ and $P(\barν_μ\rightarrow \barν_τ)$ are sensitive to these oscillation parameters. An asymmetry parameter can be defined as the difference of these two probabilities normalized to their sum. The profile of the asymmetry parameter gives a clear signal of the mass ordering as it is found to be positive for inverted hierarchy and negative for normal hierarchy. The asymmetry parame…
We explore the complementarity between LHC searches and neutrino experiments in probing neutrino non-standard interactions. Our study spans the theoretical frameworks of effective field theory, simplified model and an illustrative UV completion, highlighting the synergies and distinctive features in all cases. We show that besides constraining the allowed NSI parameter space, the LHC data can break important degeneracies present in oscillation experiments such as DUNE, while the latter play an important role in probing light and weakly coupled physics undetectable at the LHC.
LBNE (Longbaseline Neutrino Oscillation Experiments) provide a powerful experimental setup to study sensitivities and exlcusion limits in neutrino oscillation parameter space. A longbaseline experiment is being planned, at USA, from FNAL (Fermilab National Accelerator Laboratory) to an underground laboratory at Homestake in South Dakota, at an angle of 5.84 degrees from FNAL (at a distance of 1289 km). The prospect of a new beamline towards this location from FNAL, and a 300 Kiloton water Cerenkov detector at the site is in planning stage, for the studies of the neutrino physics program. The l…
At present the three major unknowns in neutrino oscillation parameters are the mass hierarchy, the octant of $θ_{23}$ and the CP phase $δ_{CP}$. It is well known that the presence of hierarchy$-δ_{CP}$ and octant degeneracies affects the unambiguous determination of these parameters. In this paper we show that a comprehensive way to study the remaining parameter degeneracies is in the form of a generalized hierarchy-$θ_{23}$ - $δ_{CP}$ degeneracy. We show that the wrong-hierarchy and/or wrong-octant solutions can be further classified into eight different solutions depending on whether they oc…
The latest data of the two long-baseline accelerator experiments NO$ν$A and T2K, interpreted in the standard 3-flavor scenario, display a discrepancy. A mismatch in the determination of the standard CP-phase $δ_{\mathrm {CP}}$ extracted by the two experiments is evident in the normal neutrino mass ordering. While NO$ν$A prefers values close to $δ_{\mathrm {CP}} \sim 0.8 π$, T2K identifies values of $δ_{\mathrm {CP}} \sim 1.4 π$. Such two estimates are in disagreement at more than 90$\%$ C.L. for 2 degrees of freedom. We show that such a tension can be resolved if one hypothesizes the existence…
Neutrino oscillations in matter provide a unique probe of new physics. Leveraging the advent of neutrino appearance data from NOvA and T2K in recent years, we investigate the presence of CP-violating neutrino non-standard interactions in the oscillation data. We first show how to very simply approximate the expected NSI parameters to resolve differences between two long-baseline appearance experiments analytically. Then, by combining recent NOvA and T2K data, we find a tantalizing hint of CP-violating NSI preferring a new complex phase that is close to maximal: $ϕ_{eμ}$ or $ϕ_{eτ}\approx3π/2$ …
