Search

The tau neutrino is the least well measured particle in the Standard Model. Most notably, the tau neutrino row of the lepton mixing matrix is quite poorly constrained when unitarity is not assumed. In this paper, we identify data sets involving tau neutrinos that improve our understanding of the tau neutrino part of the mixing matrix, in particular ντ appearance in atmospheric neutrinos. We present new results on the elements of the tau row leveraging existing constraints on the electron and muon rows for the cases of unitarity violation, with and without kinematically accessible steriles. We also show the expected sensitivity due to upcoming experiments and demonstrate that the tau neutrino row precision may be comparable to the muon neutrino row in a careful combined fit. [ABSTRACT FROM AUTHOR]

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, νBDX-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. Furthermore, we show that these experiments have the potential to test unexplored regions that, in some case, could explain the anomalous magnetic moment of the muon or peculiar spectral features in the cosmic neutrino spectrum observed by IceCube. [ABSTRACT FROM AUTHOR]

Extensions of the Standard Model (SM) with sterile neutrinos are well motivated from the observed oscillations of the light neutrinos and they have shown to successfully explain the Baryon Asymmetry of the Universe (BAU) through, for instance, the so-called ARS leptogenesis. Sterile neutrinos can be added in minimal ways to the SM, but many theories exist where sterile neutrinos are not the only new fields. Such theories often include scalar bosons, which brings about the possibility of further interactions between the sterile neutrinos and the SM. In this paper we consider an extension of the SM with two sterile neutrinos and one scalar singlet particle and investigate the effect that an additional, thermalised, scalar has on the ARS leptogenesis mechanism. We show that in general the created asymmetry is reduced due to additional sterile neutrino production from scalar decays. When sterile neutrinos and scalars are discovered in the laboratory, our results will provide information on the applicability of the ARS leptogenesis mechanism. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The possibility of Lorentz Invariance Violation (LIV) may appear in unified theories, such as string theory, which allow the existence of a new space-time structure at the Planck scale (Mp ∼ 1019 GeV). This effect can be observed at low energies with a strength of ∼ 1/Mp using the perturbative approach. In the minimal Standard Model extension (SME) framework, the neutrino mass-induced flavor oscillation gets modified in the presence of LIV. The Iron Calorimeter (ICAL) detector at the proposed India-based Neutrino Observatory (INO) offers a unique window to probe these LIV parameters by observing atmospheric neutrinos and antineutrinos separately over a wide range of baselines in the multi-GeV energy range. In this paper, for the first time, we study in detail how the CPT-violating LIV parameters (aμτ, aeμ, aeτ) can alter muon survival probabilities and expected μ− and μ+ event rates at ICAL. Using 500 kt·yr exposure of ICAL, we place stringent bounds on these CPT-violating LIV parameters at 95% C.L., which are slightly better than the present Super-Kamiokande limits. We demonstrate the advantage of incorporating hadron energy information and charge identification capability at ICAL while constraining these LIV parameters. Further, the impact of the marginalization over the oscillation parameters and choice of true values of sin2θ23 on LIV constraints is described. We also study the impact of these LIV parameters on mass ordering determination and precision measurement of atmospheric oscillation parameters. [ABSTRACT FROM AUTHOR]

SND@LHC is an approved experiment equipped to detect scatterings of neutrinos produced in the far-forward direction at the LHC, and aimed to measure their properties. In addition, the detector has a potential to search for new feebly interacting particles (FIPs) that may be produced in proton-proton collisions. In this paper, we discuss signatures of new physics at SND@LHC for two classes of particles: stable FIPs that may be detected via their scattering, and unstable FIPs that decay inside the detector. We estimate the sensitivity of SND@LHC to probe scatterings of leptophobic dark matter and decays of neutrino, scalar, and vector portal particles. Finally, we also compare and qualitatively analyze the potential of SND@LHC and FASER/FASERν experiments for these searches. [ABSTRACT FROM AUTHOR]

Recently in JHEP09 (2021) 053, Wang et al. discussed the polynomial ring formed by flavor invariants in the leptonic sector with massive Majorana neutrinos. They have explicitly constructed the finite generating sets of the polynomial rings for both two-generation scenario and three-generation scenario. However, Wang et al.'s claim of the finiteness of the generating sets of the polynomial rings and their calculation by the approach of Hilbert series with generalized Molien-Weyl formula are both based on their assertion that the unitary group U(n, ℂ) is reductive, which is unfortunately incorrect. The property of being reductive is only applicable to linear algebraic groups. And it is well-known that the unitary group U(n, ℂ) is not even a linear algebraic group. In this paper, we point out the above issue and provide a solution to fill in the accompanying logical gaps in JHEP09 (2021) 053. Some important results from the theory of linear algebraic group, the invariant theory of square matrices and group theory are needed in the analysis. We also clarify some somewhat misleading or vague statements in JHEP09 (2021) 053 about the scope of flavor invariants. Note that, although built from incorrect assertion, Wang et al.'s calculation results in JHEP09 (2021) 053 are nonetheless correct, which is ultimately because the ring of invariants of U(n, ℂ) is isomorphic to that of GL(n, ℂ) which is itself reductive. [ABSTRACT FROM AUTHOR]

The (g − 2)μ anomaly indicates that the second generation of leptons should have new interactions beyond the standard model. The high flux of νμ and ν ¯ μ at the forward experiments such as FASERν and SND@LHC makes them suitable setups to search for new interactions of the second generation leptons. In this paper, we build a model in which the second generation left-handed leptons couple to a new right-handed neutrino, N and a new Higgs doublet which also couples to the quarks. The scattering of high energy νμ off nuclei can produce N. We investigate how forward experiments can test this model by looking for the N production vertex followed by the displaced vertex of the N decay. Discovering even a single such event can be a harbinger to look for the spectacular signals of the new Higgs doublet production at the LHC. We discuss the possibility of explaining the (g − 2)μ anomaly by adding more generations of N which will lead to chain decays of N and multiple leptons with distinct signals both at forward experiments and at the CMS and ATLAS detectors. Finally, we show that by adding a new light singlet scalar mixed with the neutral component of the new Higgs doublet (i.e., 2HDM+S model), the statistics of the data sample can be dramatically increased. [ABSTRACT FROM AUTHOR]

The exchange of a pair of neutrinos between two objects, separated by a distance r, leads to a long-range effective potential proportional to 1/r5, assuming massless neutrinos and four-fermion contact interactions. In this paper, we investigate how this known form of neutrino-mediated potentials might be altered if the distance r is sufficiently short, corresponding to a sufficiently large momentum transfer which could invalidate the contact interactions. We consider two possible scenarios to open up the contact interactions by introducing a t-channel or an s-channel mediator. We derive a general formula that is valid to describe the potential in all regimes as long as the external particles remain non-relativistic. In both scenarios, the potential decreases as 1/r5 in the long-range limit as expected. In the short-range limit, the t-channel potential exhibits the Coulomb-like behavior (i.e. proportional to 1/r), while the s-channel potential exhibits 1/r4 and 1/r2 behaviors. [ABSTRACT FROM AUTHOR]

Interest in searches for heavy neutral leptons (HNLs) at the LHC has increased considerably in the past few years. In the minimal scenario, HNLs are produced and decay via their mixing with active neutrinos in the Standard Model (SM) spectrum. However, many SM extensions with HNLs have been discussed in the literature, which sometimes change expectations for LHC sensitivities drastically. In the NRSMEFT, one extends the SM effective field theory with operators including SM singlet fermions, which allows to study HNL phenomenology in a "model independent" way. In this paper, we study the sensitivity of ATLAS to HNLs in the NRSMEFT for four-fermion operators with a single HNL. These operators might dominate both production and decay of HNLs, and we find that new physics scales in excess of 20 TeV could be probed at the high-luminosity LHC. [ABSTRACT FROM AUTHOR]

Next generation neutrino oscillation experiments like DUNE and T2HK are multi-purpose observatories, with a rich physics program beyond oscillation measurements. A special role is played by their near detector facilities, which are particularly well-suited to search for weakly coupled dark sector particles produced in the primary target. In this paper, we demonstrate this by estimating the sensitivity of the DUNE near detectors to the scattering of sub-GeV DM particles and to the decay of sub-GeV sterile neutrinos ("heavy neutral leptons"). We discuss in particular the importance of the DUNE-PRISM design, which allows some of the near detectors to be moved away from the beam axis. At such off-axis locations, the signal-to-background ratio improves for many new physics searches. We find that this leads to a dramatic boost in the sensitivity to boosted DM particles interacting mainly with hadrons, while for boosted DM interacting with leptons, data taken on-axis leads to marginally stronger exclusion limits. Searches for heavy neutral leptons perform equally well in both configurations. [ABSTRACT FROM AUTHOR]

In this paper, we examine the leptonic flavor invariants in the minimal see-saw model (MSM), in which only two right-handed neutrino singlets are added into the Standard Model in order to accommodate tiny neutrino masses and explain cosmological matter-antimatter asymmetry via leptogenesis mechanism. For the first time, we calculate the Hilbert series (HS) for the leptonic flavor invariants in the MSM. With the HS we demonstrate that there are totally 38 basic flavor invariants, among which 18 invariants are CP-odd and the others are CP-even. Moreover, we explicitly construct these basic invariants, and any other flavor invariants in the MSM can be decomposed into the polynomials of them. Interestingly, we find that any flavor invariants in the effective theory at the low-energy scale can be expressed as rational functions of those in the full MSM at the high-energy scale. Practical applications to the phenomenological studies of the MSM, such as the sufficient and necessary conditions for CP conservation and CP asymmetries in leptogenesis, are also briefly discussed. [ABSTRACT FROM AUTHOR]

In this paper, we accomplish the complete one-loop matching of the type-I seesaw model onto the Standard Model Effective Field Theory (SMEFT), by integrating out three heavy Majorana neutrinos with the functional approach. It turns out that only 31 dimension-six operators (barring flavor structures and Hermitian conjugates) in the Warsaw basis of the SMEFT can be obtained, and most of them appear at the one-loop level. The Wilson coefficients of these 31 dimension-six operators are computed up to O (M−2) with M being the mass scale of heavy Majorana neutrinos. As the effects of heavy Majorana neutrinos are encoded in the Wilson coefficients of these higher-dimensional operators, a complete one-loop matching is useful to explore the low-energy phenomenological consequences of the type-I seesaw model. In addition, the threshold corrections to the couplings in the Standard Model and to the coefficient of the dimension-five operator are also discussed. [ABSTRACT FROM AUTHOR]

In the present paper, we carry out a systematic study of the flavor invariants and their renormalization-group equations (RGEs) in the leptonic sector with three generations of charged leptons and massive Majorana neutrinos. First, following the approach of the Hilbert series from the invariant theory, we show that there are 34 basic flavor invariants in the generating set, among which 19 invariants are CP-even and the others are CP-odd. Any flavor invariants can be expressed as the polynomials of those 34 basic invariants in the generating set. Second, we explicitly construct all the basic invariants and derive their RGEs, which form a closed system of differential equations as they should. The numerical solutions to the RGEs of the basic flavor invariants have also been found. Furthermore, we demonstrate how to extract physical observables from the basic invariants. Our study is helpful for understanding the algebraic structure of flavor invariants in the leptonic sector, and also provides a novel way to explore leptonic flavor structures. [ABSTRACT FROM AUTHOR]

In the quest for unification of the Standard Model with gravity, classical scale invariance can be utilized to dynamically generate the Planck mass MPl. However, the relation of Planck scale physics to the scale of electroweak symmetry breaking μH requires further explanation. In this paper, we propose a model that uses the spontaneous breaking of scale invariance in the scalar sector as a unified origin for dynamical generation of both scales. Using the Gildener-Weinberg approximation, only one scalar acquires a vacuum expectation value of υS ∼ (1016−17) GeV, thus radiatively generating M P 1 ≈ β S 1 / 2 υ S and μH via the neutrino option with right handed neutrino masses mN = yMυS ∼ 107 GeV. Consequently, active SM neutrinos are given a mass with the inclusion of a type-I seesaw mechanism. Furthermore, we adopt an unbroken Z2 symmetry and a Z2-odd set of right-handed Majorana neutrinos χ that do not take part in the neutrino option and are able to produce the correct dark matter relic abundance (dominantly) via inflaton decay. The model also describes cosmic inflation and the inflationary CMB observables are predicted to interpolate between those of R2 and linear chaotic inflationary model and are thus well within the strongest experimental constraints. [ABSTRACT FROM AUTHOR]

Electric dipole moments (EDMs) of charged leptons arise from a new source of CP violation in the lepton sector. In this paper, we calculate the EDMs of the charged leptons in the minimal scotogenic model with two singlet fermions, and the models extended with one or two triplet fermions instead of the singlet fermions, taking into account the constraints of the neutrino oscillation data, the charged lepton flavor violation and perturbative unitarity bound for the Yukawa couplings. We show that the hybrid model with one singlet and one triplet fermions predicts an electron EDM larger than the other models in both normal and inverted neutrino mass hierarchy. We find some parameter space has already been ruled out by the current upper bound of the electron EDM and further parameter space can be explored by future experiments. [ABSTRACT FROM AUTHOR]

Some models of leptogenesis involve a quasi-degenerate pair of heavy neutrinos N1,2 whose masses can be small, O(GeV). Such neutrinos can contribute to the rare lepton-number-violating (LNV) decay W ± → ℓ 1 ± ℓ 2 ± q ′ q ¯ ∓ . If both N1 and N2 contribute, there can be a CP-violating rate difference between the LNV decay of a W− and its CP-conjugate decay. In this paper, we examine the prospects for measuring such a CP asymmetry ACP at the LHC. We assume a value for the heavy-light neutrino mixing parameter |BℓN|2 = 10−5, which is allowed by the present experimental constraints, and consider 5 GeV ≤ MN≤ 80 GeV. We consider three versions of the LHC — HL-LHC, HE-LHC, FCC-hh — and show that small values of the CP asymmetry can be measured at 3σ, in the range 1% ≲ ACP ≲ 15%. [ABSTRACT FROM AUTHOR]

In the near future, the neutrinoless double-beta (0νββ) decay experiments will hopefully reach the sensitivity of a few meV to the effective neutrino mass |mββ|. In this paper, we tentatively examine the sensitivity of future 0νββ-decay experiments to neutrino masses and Majorana CP phases by following the Bayesian statistical approach. Provided experimental setups corresponding to the experimental sensitivity of |mββ| ≃ 1 meV, the null observation of 0νββ decays in the case of normal neutrino mass ordering leads to a very competitive bound on the lightest neutrino mass m1. Namely, the 95% credible interval in the Bayesian approach turns out to be 1.6 meV ≲ m1 ≲ 7.3 meV or 0.3 meV ≲ m1 ≲ 5.6 meV when the uniform prior on m1/eV or on log10(m1/eV) is adopted. Moreover, one of two Majorana CP phases is strictly constrained, i.e., 140° ≲ ρ ≲ 220° for both scenarios of prior distributions of m1. In contrast, if a relatively worse experimental sensitivity of |mββ| ≃ 10 meV is assumed, the constraint on the lightest neutrino mass becomes accordingly 0.6 meV ≲ m1 ≲ 26 meV or 0 ≲ m1 ≲ 6.1 meV, while two Majorana CP phases will be essentially unconstrained. In the same statistical framework, the prospects for the determination of neutrino mass ordering and the discrimination between Majorana and Dirac nature of massive neutrinos in the 0νββ-decay experiments are also discussed. Given the experimental sensitivity of |mββ| ≃ 10 meV (or 1 meV), the strength of evidence to exclude the Majorana nature under the null observation of 0νββ decays is found to be inconclusive (or strong), no matter which of two priors on m1 is taken. [ABSTRACT FROM AUTHOR]

Building UV completions of lepton-number-violating effective operators has proved to be a useful way of studying and classifying models of Majorana neutrino mass. In this paper we describe and implement an algorithm that systematises this model-building procedure. We use the algorithm to generate computational representations of all of the tree-level completions of the operators up to and including mass-dimension 11. Almost all of these correspond to models of radiative neutrino mass. Our work includes operators involving derivatives, updated estimates for the bounds on the new-physics scale associated with each operator, an analysis of various features of the models, and a look at some examples. We find that a number of operators do not admit any completions not also generating lower-dimensional operators or larger contributions to the neutrino mass, ruling them out as playing a dominant role in the neutrino-mass generation. Additionally, we show that there are at most five models containing three or fewer exotic multiplets that predict new physics that must lie below 100 TeV. Accompanying this work we also make available a searchable database containing all of our results and the code used to find the completions. We emphasise that our methods extend beyond the study of neutrino-mass models, and may be useful for generating completions of high-dimensional operators in other effective field theories. Example code: ref. [37]. [ABSTRACT FROM AUTHOR]

The XENON1T collaboration recently reported the excess of events from recoil electrons, possibly giving an insight into new area beyond the Standard Model (SM) of particle physics. We try to explain this excess by considering effective interactions between the sterile neutrinos and the SM particles. In this paper, we present an effective model based on one-particle-irreducible interaction vertices at low energies that are induced from the SM gauge symmetric four-fermion operators at high energies. The effective interaction strength is constrained by the SM precision measurements, astrophysical and cosmological observations. We introduce a novel effective electromagnetic interaction between sterile neutrinos and SM neutrinos, which can successfully explain the XENON1T event rate through inelastic scattering of the sterile neutrino dark matter from Xenon electrons. We find that sterile neutrinos with masses around 90 keV and specific effective coupling can fit well with the XENON1T data where the best fit points preserving DM constraints and possibly describe the anomalies in other experiments. [ABSTRACT FROM AUTHOR]

With large active volume sizes dark matter direct detection experiments are sensitive to solar neutrino fluxes. Nuclear recoil signals are induced by 8B neutrinos, while electron recoils are mainly generated by the pp flux. Measurements of both processes offer an opportunity to test neutrino properties at low thresholds with fairly low backgrounds. In this paper we study the sensitivity of these experiments to neutrino magnetic dipole moments assuming 1, 10 and 40 tonne active volumes (representative of XENON1T, XENONnT and DARWIN), 0.3 keV and 1 keV thresholds. We show that with nuclear recoil measurements alone a 40 tonne detector could be as competitive as Borexino, TEXONO and GEMMA, with sensitivities of order 8.0 × 10−11μB at the 90% CL after one year of data taking. Electron recoil measurements will increase sensitivities way below these values allowing to test regions not excluded by astrophysical arguments. Using electron recoil data and depending on performance, the same detector will be able to explore values down to 4.0 × 10−12μB at the 90% CL in one year of data taking. By assuming a 200-tonne liquid xenon detector operating during 10 years, we conclude that sensitivities in this type of detectors will be of order 10−12μB. Reducing statistical uncertainties may enable improving sensitivities below these values. [ABSTRACT FROM AUTHOR]

In the framework of the scotogenic model, which features radiative generation of neutrino masses, we explore light dark matter scenario. Throughout the paper we chiefly focus on keV-scale dark matter which can be produced either via freeze-in through the decays of the new scalars, or from the decays of next-to-lightest fermionic particle in the spectrum, which is produced through freeze-out. The latter mechanism is required to be suppressed as it typically produces a hot dark matter component. Constraints from BBN are also considered and in combination with the former production mechanism they impose the dark matter to be light. For this scenario we consider signatures at High Luminosity LHC and proposed future hadron and lepton colliders, namely FCC-hh and CLIC, focusing on searches with two leptons and missing energy as a final state. While a potential discovery at High Luminosity LHC is in tension with limits from cosmology, the situation greatly improves for future colliders. [ABSTRACT FROM AUTHOR]

In this paper we investigate neutrino oscillations with altered dispersion relations in the presence of sterile neutrinos. Modified dispersion relations represent an agnostic way to parameterize new physics. Models of this type have been suggested to explain global neutrino oscillation data, including deviations from the standard three-neutrino paradigm as observed by a few experiments. We show that, unfortunately, in this type of models new tensions arise turning them incompatible with global data. [ABSTRACT FROM AUTHOR]

Long-lived particles are predicted in extensions of the Standard Model that involve relatively light but very weakly interacting sectors. In this paper we consider the possibility that some of these particles are produced in atmospheric cosmic ray showers, and their decay intercepted by neutrino detectors such as IceCube or Super-Kamiokande. We present the methodology and evaluate the sensitivity of these searches in various scenarios, including extensions with heavy neutral leptons in models of massive neutrinos, models with an extra U(1) gauge symmetry, and a combination of both in a U(1)B−L model. Our results are shown as a function of the production rate and the lifetime of the corresponding long-lived particles. [ABSTRACT FROM AUTHOR]

The Borexino detector measures solar neutrino fluxes via neutrino-electron elastic scattering. Observed spectra are determined by the solar-νe survival probability Pee(E), and the chiral couplings of the neutrino and electron. Some theories of physics beyond the Standard Model postulate the existence of Non-Standard Interactions (NSI’s) which modify the chiral couplings and Pee(E). In this paper, we search for such NSI’s, in particular, flavor-diagonal neutral current interactions that modify the νee and ντe couplings using Borexino Phase II data. Standard Solar Model predictions of the solar neutrino fluxes for both high- and low-metallicity assumptions are considered. No indication of new physics is found at the level of sensitivity of the detector and constraints on the parameters of the NSI’s are placed. In addition, with the same dataset the value of sin2θW is obtained with a precision comparable to that achieved in reactor antineutrino experiments. [ABSTRACT FROM AUTHOR]

This is the first paper of our systematic efforts on lepton number violating (LNV) hadronic decays in the effective field theory approach. These decays provide information complementary to popular nuclear neutrinoless double-β (0νββ) decay in that they can probe LNV interactions involving heavier quarks and charged leptons. We may call them hadronic 0νββ decays in short, though β refers to all charged leptons. In this work we investigate the decays K±→ π∓l±l± that arise from short-distance or contact interactions involving four quark fields and two charged lepton fields, which have canonical dimension nine (dim-9) at leading order in low energy effective field theory (LEFT). We make a complete analysis on the basis of all dim-9 operators that violate lepton number by two units, and compute their one-loop QCD renormalization effects. We match these effective interactions in LEFT to those in chiral perturbation theory (χPT) for pseudoscalar mesons, and determine the resulting hadronic low energy constants (LECs) by chiral symmetry and lattice results in the literature. The obtained decay rate is general in that all physics at and above the electroweak scale is completely parameterized by the relevant Wilson coefficients in LEFT and hadronic LECs in χPT. Assuming the standard model effective field theory (SMEFT) is the appropriate effective field theory between some new physics scale and the electroweak scale, we match our LEFT results to SMEFT whose leading effective interactions arise from LNV dim-7 operators. This connection to SMEFT simplifies significantly the interaction structures entering in the kaon decays, and we employ the current experimental bounds to set constraints on the relevant Wilson coefficients in SMEFT. [ABSTRACT FROM AUTHOR]

In the recent years experiments have established the existence of neutrino os- cillations and most of the oscillation parameters have been measured with a good accuracy. The search for New Physics in neutrino oscillation will be an experimental concrete possi- bility in the next future. In this paper we investigate the ability of the DUNE facility to search for Non Standard Interaction (NSI) in neutrino propagation in matter, emphasizing the role of different assumptions on the shape and absolute normalization errors of both ve and vμ signals. We also study in detail the effects of NSI and systematics in the extraction of standard oscillation parameters. [ABSTRACT FROM AUTHOR]

A Standard Model extension with two Majorana neutrinos can explain the measured neutrino masses and mixings, and also account for the matter-antimatter asymmetry in a region of parameter space that could be testable in future experiments. The testability of the model relies to some extent on its minimality. In this paper we address the possibility that the model might be extended by extra generic new physics which we parametrize in terms of a low-energy effective theory. We consider the effects of the operators of the lowest dimensionality, d = 5, and evaluate the upper bounds on the coefficients so that the predictions of the minimal model are robust. One of the operators gives a new production mechanism for the heavy neutrinos at LHC via higgs decays. The higgs can decay to a pair of such neutrinos that, being long-lived, leave a powerful signal of two displaced vertices. We estimate the LHC reach to this process. [ABSTRACT FROM AUTHOR]

Minimal SO(10) grand unified models provide phenomenological predictions for neutrino mass patterns and mixing. These are the outcome of the interplay of several features, namely: i) the seesaw mechanism; ii) the presence of an intermediate scale where B-L gauge symmetry is broken and the right-handed neutrinos acquire a Majorana mass; iii) a symmetric Dirac neutrino mass matrix whose pattern is close to the up-type quark one. In this framework two natural characteristics emerge. Normal neutrino mass hierarchy is the only allowed, and there is an approximate relation involving both light-neutrino masses and mixing parameters. This differs from what occurring when horizontal flavour symmetries are invoked. In this case, in fact, neutrino mixing or mass relations have been separately obtained in literature. In this paper we discuss an example of such comprehensive mixing-mass relation in a specific realization of SO(10) and, in particular, analyse its impact on the expected neutrinoless double beta decay effective mass parameter 〈 m 〉, and on the neutrino mass scale. Remarkably a lower limit for the lightest neutrino mass is obtained ( m ≳ 7 .5 × 10 eV, at 3 σ level). [ABSTRACT FROM AUTHOR]

If neutrinos are Dirac fermions, certain new physics beyond the standard model should exist to account for the smallness of neutrino mass. With two additional scalars and a heavy intermediate fermion, in this paper, we systematically study the general mechanism that can naturally generate the tiny Dirac neutrino mass at tree and in one-loop level. For tree level models, we focus on natural ones, in which the additional scalars develop small vacuum expectation values without fine-tuning. For one-loop level models, we explore those having dark matter candidates under Z symmetry. In both cases, we concentrate on SU(2) multiplet scalars no larger than quintuplet, and derive the complete sets of viable models. Phenomenologies, such as lepton flavor violation, leptogenesis, DM and LHC signatures are briefly discussed. [ABSTRACT FROM AUTHOR]

The neutrinophilic two-Higgs-doublet model ( ν2HDM) provides a natural way to generate tiny neutrino mass from interactions with the new doublet scalar Φ ( H , H, A) and singlet neutrinos N of TeV scale. In this paper, we perform detailed simulations for the lepton number violating (LNV) signatures at LHC arising from cascade decays of the new scalars and neutrinos with the mass order $$ {m}_{N_R}

The Majoron, the Nambu-Goldstone boson of lepton number symmetry, is an interesting candidate for dark matter as it deeply connects the dark matter and neutrino physics. In this paper, we consider the Majoron dark matter as pseudo Nambu-Goldstone boson with TeV-scale mass. The heavy Majoron generally has the large decay constant and tiny Yukawa couplings to light right-handed neutrinos which are required by cosmological and astrophysical observations. That makes it difficult to realize the desired amount of the relic abundance of Majoron dark matter. We consider three improved scenarios for the generation of Majoron, dubbed as Majorogenesis, in the early universe and find in all cases the parameter space compatible with the relic abundance and cosmic-ray constraints. [ABSTRACT FROM AUTHOR]

Clockwork (CW) mechanism can explain the smallness of neutrino masses without introducing unnaturally small input parameters. In this paper we study the simplest CW neutrino model, the "uniform" clockwork, as well as a broader class of "generalized" clockwork models. We derive constraints on such models from lepton-flavor violating processes, as well as precision electroweak fits. These constraints allow excited CW neutrino states with masses of order 100 GeV–1 TeV, within reach of the LHC and proposed lepton colliders, as long as the input neutrino Yukawa coupling is of order 10−1–10−2. We study collider phenomenology of these models. At the LHC, models with light (∼ 100 GeV) CW neutrinos can be discovered using the signature. Lepton colliders will be able to discover the CW neutrinos as long as they are within their kinematic range. [ABSTRACT FROM AUTHOR]

In this Addendum we rewrite the neutrino mixing angles and mass squared differences in matter given in our original paper, [1], in a notation that is more conventiona for the reader. Replacing the usual neutrino mixing angles and mass squared differences in the expressions for the vacuum oscillation probabilities with these matter mixing angles and mass squared differences gives an excellent approximation to the oscillation probabilities in matter. Comparisons for T2K & T2HK, NOvA, T2HKK and DUNE are also given for neutrinos and anti-neutrinos, disappearance and appearance channels, and for both normal and inverted orderings. [ABSTRACT FROM AUTHOR]

In the near future, fundamental interactions at high-energy scales may be most efficiently studied via precision measurements at low energies. A universal language to assemble and interpret precision measurements is the so-called SMEFT, which is an effective field theory (EFT) where the Standard Model (SM) Lagrangian is extended by higher-dimensional operators. In this paper we investigate the possible impact of the DUNE neutrino experiment on constraining the SMEFT. The unprecedented neutrino flux offers an opportunity to greatly improve the current limits via precision measurements of the trident production and neutrino scattering off electrons and nuclei in the DUNE near detector. We quantify the DUNE sensitivity to dimension-6 operators in the SMEFT Lagrangian, and find that in some cases operators suppressed by an O30 TeV scale can be probed. We also compare the DUNE reach to that of future experiments involving atomic parity violation and polarization asymmetry in electron scattering, which are sensitive to an overlapping set of SMEFT parameters. [ABSTRACT FROM AUTHOR]

Flavor-dependent long-range leptonic forces mediated by the ultra-light and neutral bosons associated with gauged Le − Lμ or Le − Lτ symmetry constitute a minimal extension of the Standard Model. In presence of these new anomaly free abelian symmetries, the SM remains invariant and renormalizable, and can lead to interesting phenomenological consequences. For an example, the electrons inside the Sun can generate a flavor-dependent long-range potential at the Earth surface, which can enhance νμ and ν¯μ survival probabilities over a wide range of energies and baselines in atmospheric neutrino experiments. In this paper, we explore in detail the possible impacts of these long-range flavor-diagonal neutral current interactions due to Le − Lμ and Le − Lτ symmetries (one at-a-time) in the context of proposed 50 kt magnetized ICAL detector at INO. Combining the information on muon momentum and hadron energy on an event-by-event basis, ICAL will be sensitive to long-range forces at 90% (3σ) C.L. with 500 kt·yr exposure if the effective gauge coupling αeμ/eτ> 1.2 × 10−53 (1.75 × 10−53). The sensitivity of ICAL towards αeμ (αeτ) is ∼ 46 (53) times better than the existing bound from the Super-Kamiokande experiment at 90% C.L., and at 3σ, the sensitivity of ICAL is comparable to the bounds obtained from the combined solar and KamLAND data. [ABSTRACT FROM AUTHOR]