New limits for the Violation of Equivalence Principle (VEP) are obtained considering the mass-flavor mixing hypothesis. This analysis includes observations of solar and reactor neutrinos and has obtained a limit for the VEP parameter $|Δγ|$ contributing to the $ν_e$ and $\barν_e$ disappearance channels of the order $|Δγ|<10^{-14}$, when it is assumed that neutrinos are mainly affected by the gravitational potential $φ\approx 10^{-5}$ due to the Great Attractor.
We investigate the impact of a fourth sterile neutrino at reactor and Spallation Neutron Source neutrino detectors. Specifically, we explore the discovery potential of the TEXONO and COHERENT experiments to subleading sterile neutrino effects through the measurement of the coherent elastic neutrino-nucleus scattering event rate. Our dedicated $χ^2$-sensitivity analysis employs realistic nuclear structure calculations adequate for high purity sub-keV threshold Germanium detectors.
In this work, we have explored the possibilities of improving CP violation discovery potential of newly planned Long-Baseline Neutrino Experiment (LBNE), U.S.A., by combining with data from reactors. The third mixing angle $θ_{13}$ is now very precisely measured and this precise measurenent of $θ_{13}$ helps in measurement of CP violation. Here, CP violation is studied with and without data from reactors. Impact of placing a ND is also studied. It is found that CPV discovery potential of LBNE with ND increases when combined with data from reactors. With a far detector of 35 kt, it is possible …
Most neutrino mass extensions of the standard electroweak model entail non-standard interactions which, in the low energy limit, can be parametrized in term of effective four-fermion operators $ν_αν_β\bar f f $. Typically of sub-weak strength, $ε_{αβ} G_F$, these are characterized by dimensionless coupling parameters, $ε_{αβ}$, which may be relatively sizeable in a wide class of schemes. Here we focus on non-universal (NU) flavor conserving couplings ($α= β$) with electrons ($f = e$) and analyse their impact on the phenomenology of solar neutrinos. We consistently take into account their effec…
We perform a detailed combined fit to the $\overline ν_e \rightarrow \overline ν_e$ disappearence data of the Daya Bay experiment and the appearance $ν_μ \rightarrow ν_{e}$ and disappearance $ν_μ \rightarrow ν_μ$ data of the Tokai to Kamioka (T2K) one in the presence of two models of new physics affecting neutrino oscillations, namely a model where sterile neutrinos can propagate in a large compactified extra dimension and a model where non-standard interactions (NSI) affect the neutrino production and detection. We find that the Daya Bay $\oplus$ T2K data combination constrains the largest ra…
We explore how well reactor antineutrino experiments can constrain or measure the loss of quantum coherence in neutrino oscillations. We assume that decoherence effects are encoded in the size of the neutrino wave-packet, $σ$. We find that the current experiments Daya Bay and the Reactor Experiment for Neutrino Oscillation (RENO) already constrain $σ>1.0\times 10^{-4}$ nm and estimate that future data from the Jiangmen Underground Neutrino Observatory (JUNO) would be sensitive to $σ<2.1\times 10^{-3}$ nm. If the effects of loss of coherence are within the sensitivity of JUNO, we expect $σ$ to …
In this work we study the phenomenological consequences of the existence of long-range forces coupled to lepton flavour numbers in solar neutrino oscillations. We study electronic forces mediated by scalar, vector or tensor neutral bosons and analyze their effect on the propagation of solar neutrinos as a function of the force strength and range. Under the assumption of one mass scale dominance, we perform a global analysis of solar and KamLAND neutrino data which depends on the two standard oscillation parameters, Δm^2_{21} and \tan^2θ_{12}, the force coupling constant, its range and, for the…
In this work, we present a realistic analysis of the potential of the present-day reactor experiments Double Chooz, Daya Bay and RENO for probing the existence of sterile neutrinos. We present exclusion regions for sterile oscillation parameters for each of these experiments, using simulations with realistic estimates of systematic errors and detector resolutions, and compare the sterile parameter sensitivity regions we obtain with the existing bounds from other reactor experiments. We find that these experimental set-ups give significant bounds on the parameter Θ_{ee} especially in the low st…
New limits on the weak mixing angle and on the electron neutrino effective charge radius in the low energy regime, below 100 MeV, are obtained from a combined fit of all electron-(anti)neutrino electron elastic scattering measurements. We have included the recent TEXONO measurement with a CsI (Tl) detector. Only statistical error of this measurement has been taken into account. Weak mixing angle is found to be sin^2 theta_W = 0.255 +0.022 -0.023. The electron neutrino effective charge radius squared is bounded to be r^2 = (0.9 +0.9 -1.0) x 10^{-32} cm^2. The sensitivity of future low energy ne…
We formulate the equivalence between the longitudinal weak-boson and the Goldstone boson as a criterion for sensitively probing the electroweak symmetry breaking mechanism and develop a precise power counting rule for chiral Lagrangian formulated electroweak theories. With these we semi-quatitatively analyze the sensitivities to various effective operators related to electrowaeak symmetry breaking via weak-boson scatterings at the CERN Large Hadron Collider (LHC).
Medium baseline reactor experiments (Double Chooz, Daya Bay and RENO) provide a unique opportunity to test the presence of light sterile neutrinos. We analyze the data of these experiments in the search of sterile neutrinos and also test the robustness of theta_13 determination in the presence of sterile neutrinos. We show that existence of a light sterile neutrino state improves the fit to these data moderately. We also show that the measured value of theta_{13} by these experiments is reliable even in the presence of sterile neutrinos, and the reliability owes significantly to the Daya Bay a…
Based upon our recent study on the Lorentz non-invariance ambiguity in the longitudinal weak-boson scatterings and the precise conditions for the validity of the Equivalence Theorem (ET), we further examine the intrinsic connection between the longitudinal weak-boson scatterings and probing the electroweak symmetry breaking (EWSB) mechanism. We reveal the profound physical content of the ET as being able to discriminate processes which are insensitive to probing the EWSB sector. With this physical content as a criterion, we analyze the sensitivities to various effective operators for probing t…
Sterile neutrino conversion in meter scale baselines can be sensitively probed using monoenergetic, sub-MeV, flavor pure e-neutrinos from an artificial MCi source and the unique technology of LENS designed to oberve the low energy solar neutrino spectrum via tagged CC e-neutrino capture in 115-In. Active-sterile oscillations can be directly observed in the granular LENS detector itself to critically test and extend resuls of short baseline accelerator and reactor experiments.
We examine relation between neutrino oscillation parameters and prediction of lepton flavor violation, in light of deviations from tri-bimaximal mixing. Our study shows that upcoming experimental searches for lepton flavor violation process can provide useful implications for neutrino mass spectrum and mixing angles. With simple structure of heavy right-handed neutrino and supersymmetry breaking sectors, the discovery of tau \to mu gamma decay determines neutrino mass hierarchy if large (order 0.1) reactor angle is established.
We review the current status of the neutrino mass and mixing parameters needed to reconstruct the neutrino mass matrix. A comparative study of the precision in the measurement of oscillation parameters expected from the next generation solar, atmospheric, reactor and accelerator based experiments is presented. We discuss the potential of $0νββ$ experiments in determining the neutrino mass hierarchy and the importance of a better $θ_{12}$ measurement for it.
We examine the Lorentz non-invariance ambiguity in longitudinal weak-boson scatterings and the precise conditions for the validity of the Equivalence Theorem (ET). {\it Safe} Lorentz frames for applying the ET are defined, and the intrinsic connection between the longitudinal weak-boson scatterings and probing the symmetry breaking sector is analyzed. A universal precise formulation of the ET is presented for both the Standard Model and the Chiral Lagrangian formulated Electro-Weak Theories. It is shown that in electroweak theories with strongly interacting symmetry breaking sector, the longit…
Terrestrial Matter Effects on Reactor Antineutrino Oscillations: Constant vs. Fluctuated Density Profiles
Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所）；East China University of Technology（华东理工大学）；Institute of Geology and Geophysics, Chinese academy of sciences（中国科学院地质与地球物理研究所）；Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）
We examine the possible tests of violation of the gravitational equivalence principle (VEP) at a muon storage ring via neutrino oscillation experiments. If the gravitational interactions of the neutrinos are not diagonal in the flavour basis and the gravitational interaction eigenstates have different couplings to the gravitational field, this leads to the neutrino oscillation. If one starts with $μ^+$ beam then appearance of $τ^\pm$, $e ^+$ and $μ^-$ in the final state are the signals for neutrino oscillation. We have estimated the number of $μ^-$ events in this scenario in $ν_μ-N$ deep inela…
Based upon our recent study on the intrinsic connection between the longitudinal weak-boson scatterings and probing the electroweak symmetry breaking (EWSB) mechanism, we reveal the profound physical content of the Equivalence Theorem (ET) as being able to discriminate physical processes which are sensitive/insensitive to probing the EWSB sector. With this physical content of the ET as a criterion, we analyze the complete set of the bosonic operators in the electroweak chiral Lagrangian and systematically classify the sensitivities to probing all these operators at the CERN LHC via the weak-bo…
Constraints on Light Sterile Neutrinos and Scalar Non-Standard Interactions Using the First Reactor Antineutrino Oscillation Results at JUNO
Tecnológico Nacional de México/ITS de Jerez（墨西哥国立理工学院/赫雷斯理工学院）；Instituto de Física, Universidad Nacional Autónoma de México（墨西哥国立自治大学物理研究所）；Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México（墨西哥国立自治大学理学院物理系）
We investigate neutrino mass matrix phenomenology involving scaling ansatz and texture zeros adhering inverse seesaw mechanism. It is seen that four is the maximum number of zeros in $m_D$ and $μ$ to obtain viable phenomenology. Depending upon the generic nature of the effective neutrino mass matrices we classify all the emerged matrices in four categories. One of them is ruled out phenomenologically due to inappropriate value of reactor mixing angle after breaking of the scaling ansatz. The mass ordering is inverted in all cases. One of the distinguishable feature of all these categories is t…
The oscillation of neutrino flavors, due to its interferometry nature, is extremely sensitive to the phase differences developing during the propagation of neutrinos. In this paper we investigate the effect of the Violation of Equivalence Principle (VEP) on the flavor oscillation probabilities of atmospheric and cosmic neutrinos observed at neutrino telescopes such as IceCube. Assuming a general parameterization of VEP, dubbed extended parameter space, we show that the synergy between the collected data of high energy atmospheric and cosmic neutrinos severely constrains the VEP parameters. Als…
There is an observed deficit of about 6\% in the expected rate of anti-neutrino interactions when averaging over many different reactor experiments. While the significance of the deficit is low (98.6 \% CL), there is speculation that a non-interacting "sterile" neutrino could be the cause. In this paper we explore the possibility of a two-reactor/one-detector experiment at intermediate distances (100-500 meters) to look for a sterile neutrino in the mass range implied by this deficit. A method for probing $Δm^2$ phase space is developed using interference patterns between two oscillated spectr…
Light neutral mediators, with mass $\lesssim 1$ GeV, are common features of extensions to the Standard Model (SM). Current astrophysical and terrestrial experiments have constrained the model parameter space, and planned experiments around the world promise continued improvement in sensitivity. In this paper we study the prospects for probing light neutral mediators using terrestrial stopped pion and reactor sources in combination with ultra-low threshold nuclear and electron recoil detectors. We show that the coherent neutrino-nucleus and neutrino-electron scattering channels provide compleme…
It is shown that, if the "new neutrino" implied by the Reactor Neutrino Anomaly exists and is in fact characterized by the suggested relatively high mass squared difference and reasonably large mixing angle, it should clearly reveal itself in the oscillometry measurements. For a judicious neutrino source the "new oscillation length L14 is expected shorter than 3m. Thus the needed measurements can be implemented with a gaseous spherical TPC of modest dimensions with a very good energy and position resolution, detecting nuclear recoils following the coherent neutrino-nucleus elastic scattering. …
We explore the potential of current and next generation of coherent elastic neutrino-nucleus scattering (CE$ν$NS) experiments in probing neutrino electromagnetic interactions. On the basis of a thorough statistical analysis, we determine the sensitivities on each component of the Majorana neutrino transition magnetic moment (TMM), $\left \vert Λ_i \right \vert$, that follow from low-energy neutrino-nucleus experiments. We derive the sensitivity to neutrino TMM from the first CE$ν$NS measurement by the COHERENT experiment, at the Spallation Neutron Source. We also present results for the next p…
Future experiments dedicated to the detection of Coherent Elastic Neutrino-Nucleus Scattering may be powerful tools in probing light new physics. In this paper we study the sensitivity on light $Z'$ mediators of two proposed experiments: a directional low pressure Time Projection Chamber detector, $ν$BDX-DRIFT, that will utilize neutrinos produced at the Long Baseline Neutrino Facility, and several possible experiments to be installed at the European Spallation Source. We compare the results obtained with existing limits from fixed-target, accelerator, solar neutrino and reactor experiments. F…
This paper investigates the decays from heavy higgsino-like weak-doublets into Z, h bosons and missing particles. When pair-produced at the LHC, the subsequent Z, h to 2l, 2b decays in the doublet decay cascade can yield 4l, 2l 2b, and 4b + MET + jets final states. Mutual observation of any two of these channels would provide information on the the associated doublets' decay branching fractions into a Z or h, thereby probing the Goldstone equivalence relation, shedding additional light on the Higgs sector of beyond the Standard Model theories, and facilitating the discrimination of various con…
We explore the complementarity between terrestrial neutrino oscillation experiments and astrophysical/cosmological measurements in probing the existence of sterile neutrinos. We find that upcoming accelerator neutrino experiments will not improve on constraints by the time they are operational, but that reactor experiments can already probe parameter space beyond the reach of Planck. We emphasize the tension between cosmological experiments and reactor antineutrino experiments and enumerate several possibilities for resolving this tension.
We study how lepton flavor violation (LFV) is related to the reactor angle $θ_{13}$, LHC/dark matter (DM) signal with a successful leptogenesis in a radiative seesaw model through $A_4$ flavor symmetry breaking, in the light of the deviation of tri-bimaximal mixing (TBM) angles and the recent precision oscillation data. To do this, we consider the normal mass spectrum of light neutrino giving a successful leptogenesis at electroweak (EW) scale or more with a relatively large $\sinθ_{13}\simeq{\cal O}(0.1)$, where a successful leptogenesis requires LHC/DM signal $m_{-}\lesssim$ a few keV in our…
Many models of quintessence predict a time variation of the fundamental constants as well as a composition-dependent gravity like long-range force mediated by the cosmon. We present bounds for the cosmon coupling to matter and radiation within a grand unified framework. The unification scale, the unified gauge coupling and the Fermi scale are allowed to vary independently. We find that the variation of the weak scale compared to the nucleon mass is severely restricted. The violation of the equivalence principle turns out to be substantially larger than in models where only the electromagnetic …
Based upon our recent study, we reveal the profound physical content of the longitudinal-Goldstone boson equivalence theorem as being able to discriminate physical processes which are sensitive/insensitive to probing the electroweak symmetry breaking (EWSB) sector. We then develop a precise electroweak power counting rule (a generalization from Weinberg's counting method) to `separately' count the power dependences on the energy E and all relevant mass scales. With these, we analyze the complete set of the bosonic operators in the electroweak chiral Lagrangian and systematically estimate and c…
The most general supersymmetric seesaw mechanism has too many parameters to be predictive and thus can not be excluded by any measurements of lepton flavour violating (LFV) processes. We focus on the simplest version of the type-I seesaw mechanism assuming minimal supergravity boundary conditions. We compute branching ratios for the LFV scalar tau decays, ${\tilde τ}_2 \to (e,μ) + χ^0_1$, as well as loop-induced LFV decays at low energy, such as $l_i \to l_j + γ$ and $l_i \to 3 l_j$, exploring their sensitivity to the unknown seesaw parameters. We find some simple, extreme scenarios for the un…
Future galactic supernovae will provide an extremely long baseline for studying the properties and interactions of neutrinos. In this paper, we discuss the possibility of using such an event to constrain (or discover) the effects of exotic physics in scenarios that are not currently constrained and are not accessible with reactor or solar neutrino experiments. In particular, we focus on the cases of neutrino decay and quantum decoherence. We calculate the expected signal from a core-collapse supernova in both current and future water Cerenkov, scintillating, and liquid argon detectors, and fin…
Leptonic CP Violating Phase $ δ_{CP} $ in the light neutrino sector and leptogenesis via present matter antimatter asymmetry of the Universe entails each other. Probing CP violation in light neutrino oscillation is one of the challenging tasks today. The reactor mixing angle $ θ_{13} $ measured in reactor experiments, LBL, DUNE with high precision in neutrino experiments indicates towards the vast dimension of scope to detect $ δ_{CP} $. The correlation between leptonic Dirac CPV phase $ δ_{CP} $, reactor mixing angle $ θ_{13} $, lightest neutrino mass $ m_{1} $ and matter antimatter asymmetry…
The joint realm of quantum mechanics and the general-relativistic description of gravitation is becoming increasingly accessible to terrestrial experiments and observations. In this essay we study the emerging indications of the violation of equivalence principle (VEP). While the solar neutrino anomaly may find its natural explanation in a VEP, the statistically significant discrepancy observed in the gravitationally induced phases of neutron interferometry seems to be the first indication of a VEP. However, such a view would seem immediately challenged by the atomic interferometry results. Th…
Neutrino-electron scattering can be used to probe neutrino electromagnetic properties at low-threshold underground detectors with good angular and recoil electron energy resolution. We propose to do this using a number of artificial neutrino and anti-neutrino sources such as $^{51}Cr_{24}$ and $^{90}Sr-Y$. The neutrino flux is known to within one percent, in contrast to the reactor case and one can reach lower neutrino energies. For the $^{90}Sr-Y$ source we estimate that the signal expected for a neutrino magnetic moment of $μ_ν=6 \times 10^{-11}μ_{B}$ will be comparable to that expected in t…
In models with Large Extra Dimensions the smallness of neutrino masses can be naturally explained by introducing gauge singlet fermions which propagate in the bulk. The Kaluza-Klein modes of these fermions appear as towers of sterile neutrino states on the brane. We study the phenomenological consequences of this picture for the high energy atmospheric neutrinos. For this purpose we construct a detailed equivalence between a model with large extra dimensions and a (3 + n) scenario consisting of three active and n extra sterile neutrino states, which provides a clear intuitive understanding of …
The Super-light Sterile Neutrino Scenario (SSNS) has been proposed in the literature to explain the suppression of the upturn in the low energy solar data. In this scenario, the mass splitting between the new mass eigenstate, $ν_0$ and the standard $ν_1$ is of order of $Δm_{01}^2\sim 10^{-5}$ eV$^2$. Reactor neutrino experiments with baseline larger than $\sim$20 km can help us to probe this scenario. We study the potential of upcoming JUNO and RENO-50 reactor experiments for discovering the superlight sterile neutrino or constraining its mixing parameters. We study the dependence of sensitivi…
We perform a thorough analysis of oscillation signals generated by one extra sterile neutrino, extending previous analyses done in simple limiting cases and including the effects of established oscillations among active neutrinos. We consider the following probes: solar, atmospheric, reactor and beam neutrinos, Big-Bang Nucleosynthesis (helium-4, deuterium), Cosmic Microwave Background, Large Scale Structure, supernovae, neutrinos from other astrophysical sources. We find no evidence for a sterile neutrino in present data, identify the still allowed regions, and study which future experiments …
In this article we consider the presence of neutrino non-standard interactions (NSI) in the production and detection processes of reactor antineutrinos at the Daya Bay experiment. We report for the first time, the new constraints on the flavor non-universal and flavor universal charged-current NSI parameters, estimated using the currently released 621 days of Daya Bay data. New limits are placed assuming that the new physics effects are just inverse of each other in the production and detection processes. With this special choice of the NSI parameters, we observe a shift in the oscillation amp…
We discuss the capabilities of a future neutrino factory based on intense neutrino beams from a muon storage ring to explore the non-standard neutrino matter interactions, which are assumed to be sub-leading effects in the standard mass induced neutrino oscillations. The conjunction of these two mechanisms will magnify fake CP violating effect in the presence of matter which is not coming from the CP phase in the neutrino mixing matrix. We show that such fake CP violation can be observed in neutrino factory experiments by measuring the difference between the neutrino and anti-neutrino probabil…
We discuss the limits on the neutrino magnetic moment and hypothetical interactions with a hidden unparticle sector, coming from the first neutrino data release of the Borexino experiment. The observed spectrum in Borexino depends weakly on the solar model used in the analysis, since most of the signal comes from the mono-energetic 7Be neutrinos. This fact allows us to calibrate the nu-e scattering cross section through the spectral shape. In this way, we have derived a limit on the magnetic moment for the neutrinos coming from the Sun (in which a nu_mu and nu_tau component is present): mu_nu<…
The Jiangmen Underground Neutrino Observatory (JUNO) project aims at probing, at the same time, the two main frequencies of three-flavor neutrino oscillations, as well as their interference related to the mass ordering (normal or inverted), at a distance of ~53 km from two powerful reactor complexes in China, at Yangjiang and Taishan. In the latter complex, the unoscillated spectrum from one reactor core is planned to be closely monitored by the Taishan Antineutrino Observatory (TAO), expected to have better resolution (x 1/2) and higher statistics (x 30) than JUNO. In the context of neutrino …
We discuss prospects for probing short-range sterile neutrino oscillation using neutrino-nucleus coherent scattering with ultra-low energy ($\sim 10$ eV - 100 eV) recoil threshold cryogenic Ge detectors. The analysis is performed in the context of a specific and contemporary reactor-based experimental proposal, developed in cooperation with the Nuclear Science Center at Texas A\&M University, and references developing technology based upon economical and scalable detector arrays. The baseline of the experiment is substantially shorter than existing measurements, as near as about 2 meters from …
Exotic explanations are considered for atmospheric neutrino observations. Our analysis includes matter effects and the mixing of all three neutrinos under the simplifying assumption of only one relevant mixing scale. Constraints from accelerator, reactor and solar neutrinos are included. We find that the proposed mixing mechanisms based on violations of Lorentz invariance or on violations of the equivalence principle cannot explain the recent observations of atmospheric neutrino mixing. However the data still allow a wide range of energy dependences for the vacuum mixing scale, and also allow …
Measurements of flavor ratios of astrophysical neutrino fluxes are sensitive to the two yet unknown mixing parameters $θ_{13}$ and $δ$ through the combination $\sinθ_{13}\cosδ$. We extend previous studies by considering the possibility that neutrino fluxes from more than a single type of sources will be measured. We point out that, if reactor experiments establish a lower bound on $θ_{13}$, then neutrino telescopes might establish an upper bound on $|\cosδ|$ that is smaller than one, and by that prove that CP is violated in neutrino oscillations. Such a measurement requires several favorable i…
We study cosmological models that contain sterile neutrinos with eV-range masses as suggested by reactor and short-baseline oscillation data. We confront these models with both precision cosmological data (probing the CMB decoupling epoch) and light-element abundances (probing the BBN epoch). In the minimal LambdaCDM model, such sterile neutrinos are strongly disfavoured by current data because they contribute too much hot dark matter. However, if the cosmological framework is extended to include also additional relativistic degrees of freedom -- beyond the three standard neutrinos and the put…
