Non-standard Interactions Research Articles

Radiative corrections to the τ−→(P1P2)−vτ ( P1,2=π,K ) decays

The radiative corrections to the τ−→(P1P2)−ντ (P1,2=π, K) decays are calculated for the first time including the structure-dependent real photon corrections, which are obtained using resonance chiral theory. Our results, whose uncertainty is dominated by the model dependence of the resummation of the radiative corrections and the missing virtual structure-dependent contributions, allow for precise tests of Cabibbo-Kobayashi-Maskawa unitarity, lepton flavor universality, and nonstandard interactions. Published by the American Physical Society 2024

Decay process within the QCDSR approach* *Supported in part by the National Natural Science Foundation of China (12265010, 12265009) and the Project of Guizhou Provincial Department of Science and Technology (ZK[2021]024, ZK[2023]142)

In this paper, we investigate the charmed meson rare decay process using an approach based on QCD sum rules. First, the pion twist-2, 3 distribution amplitude (DA) moments and are calculated up to the tenth and fourth orders, respectively, in the QCD sum rules according to the background field theory. After constructing the light-cone harmonic oscillator model for the pion twist-2, 3 DAs, we obtain their behaviors by matching the calculated ξ-moments. Then, the transition form factors (TFFs) are calculated using an approach based on QCD light-cone sum rules. The vector form factor at the large recoil region is . Using the rapidly converging simplified series expansion of , we present the TFFs and corresponding angular coefficients in the whole squared momentum transfer physical region. Based on non-standard neutrino interactions, the decay can be related to the decay indirectly. Thus, we first describe the semileptonic decay process , differential decay widths, and branching fraction with . The differential/total predictions for forward-backward asymmetry, -differential flat terms, and lepton polarization asymmetry are also reported. The prediction for the branching fraction is .

GRB221009A gamma-ray events from nonstandard neutrino self-interactions

The flux of high-energy astrophysical neutrinos observed by the present generation of neutrino detectors has already indicated a few hints of new physics beyond the Standard Model. In this work, we show that high-energy gamma-ray observations can also be considered as a complementary probe for unveiling the source of high-energy astrophysical neutrino events and new physics. Recently, the LHAASO collaboration has reported O(5000) gamma-ray events in the energy range between 0.5–18 TeV from gamma-ray burst GRB 221009A within 2000 seconds after the initial outburst. We showed that some of the high-energy gamma rays can be produced from the interaction of astrophysical neutrinos with CMB neutrinos through nonstandard self-interaction of neutrinos mediated by light scalar bosons. The nonstandard interaction of neutrinos recently took a lot of attention in cosmology for its role in reducing Hubble tension. We have constrained the parameter space of nonstandard self-interacting neutrinos from the flux of photons observed by LHAASO and showed consistency of the same with the resulting parameter space from Hubble tension requirements and other recent constraints from laboratory/cosmology. Published by the American Physical Society 2024

DUNE potential as a new physics probe

Neutrino experiments, in the next years, aim to determine with precision all the six parameters of the three-neutrino standard paradigm. The complete success of the experimental program is, nevertheless, attached to the non-existence (or at least smallness) of Non-Standard Interactions (NSI). In this work, anticipating the data taken from long-baseline neutrino experiments, we map all the weakly coupled theories that could induce sizable NSI, with the potential to be determined in these experiments, in particular DUNE. Once present constraints from other experiments are taken into account, in particular charged-lepton flavor violation, we find that only models containing leptoquarks (scalar or vector) and/or neutral isosinglet vector bosons are viable. We provide the explicit matching formulas connecting weakly coupled models and NSI, both in propagation and production. Departing from the weakly coupled completion with masses at TeV scale, we also provide a global fit on all NSI for DUNE, finding that NSI smaller than 10−2 cannot be probed even in the best-case scenario.

Dirac-Majorana neutrinos distinction in four-body decays

A novel method to differentiate the effects of Dirac and Majorana (D-M) neutrinos in four-body decays has been discussed in [C. S. Kim , Inferring the nature of active neutrinos: Dirac or Majorana?, .]. There, it is concluded that the back-to-back kinematic scenario seems to avoid the constraint imposed by the “practical Dirac-Majorana confusion theorem,” as one does not need to fully integrate over neutrino and antineutrino momenta. In this paper, we propose to analyze radiative leptonic lepton-decays (ℓ→ℓ′νν¯γ), as an independent alternative process to study the possible Majorana nature of neutrinos. Our approach demonstrates that, in the back-to-back kinematic configuration (for the ℓ′−γ and ν−ν¯ systems, respectively), the distinction between Dirac and Majorana cases disappears when the inaccessible neutrino angle is integrated out, which might appear unexpected considering the claims in [C. S. Kim , Inferring the nature of active neutrinos: Dirac or Majorana?, .]. Our results apply in absence of nonstandard interactions, which can enhance generally the sensitivity to the neutrino nature. Published by the American Physical Society 2024

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.

Implications of NSI constraints from ANTARES and IceCube on a simplified Z′ model

Recently the neutrino experiments ANTARES and IceCube have released new constraints to the non-standard neutrino interaction (NSI) parameter ϵμτd (flavor off-diagonal). These new constraints are stronger than those obtained from a combination of COHERENT and neutrino oscillation data. In the light of the recent constraints from ANTARES and IceCube data on the NSI parameter ϵμτd, in this work, we study the new physics implications on the parameter space of a simplified Z′ model with lepton flavor violating (μτ) couplings. For a Z′ boson with a mass heavier than the τ lepton, our results show that ANTARES and IceCube can provide additional constraints to such a new physics scenario with μτ couplings, when compared to bounds from low-energy flavor physics. Moreover, these neutrino experiments can exclude a similar region than ATLAS experiment, showing the potential to provide complementary information to the one obtained from direct searches at the Large Hadron Collider. The impact of the expected sensitivity at DUNE and Belle II experiments is also studied.

Intrusive effects of dual-tip conductivity probes on bubble measurements in a wide velocity range

High-velocity air-water flows in hydraulic structures, such as spillways and low-level outlets, are characterised by high turbulence levels and strong self-aeration. In air-water flows, the void fraction varies from values close to zero at the invert up to near unity in the upper spray region. Because of the strong aeration, non-intrusive optical measurement techniques can only be applied to a limited extent, and intrusive phase-detection probes are widely used to estimate air-water flow properties, including void fraction, interfacial velocity, and chord sizes. However, these probes are often used without independent validation. Herein, this study systematically investigated the uncertainties of phase-detection probe measurements of individual bubbles traveling at a wide range of velocities (up to 7.5 m/s) in a vertically upward bubbly pipe flow. Velocities and chord times of air bubbles were simultaneously measured with an intrusive dual-tip conductivity probe and stereo-view high-speed videos, and a comparative analysis identified various effects of bubble-probe interactions on the measurement accuracy of the bubble velocities. The bubble deceleration due to these bubble-probe interactions were quantified. For standard interactions (i.e., bubbles undergoing no significant deformation and slowing down), the velocity estimates compared well with a theoretical model (errors less than 2 %), while larger errors were found for non-standard interactions such as those characterised by crawling, drifting, and waking mechanisms. In addition, a novel correction scheme for chord times was proposed, improving the accuracy of chord length, bubble size and void fraction estimations in air-water flows.

Non-universality of leptons as a source of new physics from tree level interactions of pseudoscalar mesons

This article is based on the study of pure leptonic decays of charged pseudoscalar mesons taking non-universality into account. We calculate the branching ratios of the processes π±,K±,D±,Ds±,B±. For the search for new physics (NP), we examine the discrepancies between theoretical and experimental results. The discrepancies are possibly due to massive neutrinos, processed massless in the Standard Model (SM), and universal coupling of leptons. We focus on the non-universality of leptons in order to find the bounds on Non-Standard Interaction (NSI) parameters ɛ. We use charge current like NSI and conclude that these decays could provide strong constraints on the NSI parameter.

Radiative corrections and new physics tests in semileptonic tau decays

I review recent advances in the computation of radiative corrections in one- and two-meson tau decays and sketch their main applications in new physics tests: of lepton universality and CKM unitarity, as well as searching for non-standard interactions.

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.

Global constraints on non-standard neutrino interactions with quarks and electrons

We derive new constraints on effective four-fermion neutrino non-standard interactions with both quarks and electrons. This is done through the global analysis of neutrino oscillation data and measurements of coherent elastic neutrino-nucleus scattering (CEνNS) obtained with different nuclei. In doing so, we include not only the effects of new physics on neutrino propagation but also on the detection cross section in neutrino experiments which are sensitive to the new physics. We consider both vector and axial-vector neutral-current neutrino interactions and, for each case, we include simultaneously all allowed effective operators in flavour space. To this end, we use the most general parametrization for their Wilson coefficients under the assumption that their neutrino flavour structure is independent of the charged fermion participating in the interaction. The status of the LMA-D solution is assessed for the first time in the case of new interactions taking place simultaneously with up quarks, down quarks, and electrons. One of the main results of our work are the presently allowed regions for the effective combinations of non-standard neutrino couplings, relevant for long-baseline and atmospheric neutrino oscillation experiments.

Probing non-standard neutrino interactions with interference: insights from dark matter and neutrino experiments

Neutrino-electron scattering experiments play a crucial role in investigating the non-standard interactions of neutrinos.In certain models, these interactions can include interference terms that may affect measurements.Next-generation direct detection experiments, designed primarily for dark-matter searches, are also getting sensitive to probe the neutrino properties.We utilise the data from XENONnT, a direct detection experiment, and Borexino, a low-energy solar neutrino experiment, to investigate the impact of interference on non-standard interactions.Our study considers models with an additional U(1) B-L , including U(1), U(1) L e - L µ , and U(1) L e - L τ , to investigate the impact of interference on non-standard neutrino interactions. We demonstrate that this interference can lead to a transition between the considered non-standard interaction models in the energy range relevant to both the XENONnT and Borexino experiments.This transition can be used to distinguish among the considered models if any signals are observed at direct detection or neutrino experiments.Our findings underscore the importance of accounting for the interference and incorporating both direct detection and solar neutrino experiments to gain a better understanding of neutrino interactions and properties.

Analytic neutrino oscillation probabilities

In the work, we derive exact analytic expressions for (3+N)(3+N)-flavor neutrino oscillation probabilities in an arbitrary matter potential in term of matrix elements and eigenvalues of the Hamiltonian. With the analytic expressions, we demonstrate that nonunitary and nonstandard neutrino interaction scenarios are physically distinct: they satisfy different identities and can in principle be distinguished experimentally. The analytic expressions are implemented in a public code NuProbe, a tool for probing new physics through neutrino oscillations.

A direct detection view of the neutrino NSI landscape

In this article, we study the potential of direct detection experiments to explore the parameter space of general non-standard neutrino interactions (NSI) via solar neutrino scattering. Due to their sensitivity to neutrino-electron and neutrino-nucleus scattering, direct detection provides a complementary view of the NSI landscape to that of spallation sources and neutrino oscillation experiments. In particular, the large admixture of tau neutrinos in the solar flux makes direct detection experiments well-suited to probe the full flavour space of NSI. To study this, we develop a re-parametrisation of the NSI framework that explicitly includes a variable electron contribution and allows for a clear visualisation of the complementarity of the different experimental sources. Using this new parametrisation, we explore how previous bounds from spallation source and neutrino oscillation experiments are impacted. For the first time, we compute limits on NSI from the first results of the XENONnT and LUX-ZEPLIN experiments, and we obtain projections for future xenon-based experiments. These computations have been performed with our newly developed software package, SNuDD. Our results demonstrate the importance of using a more general NSI parametrisation and indicate that next generation direct detection experiments will become powerful probes of neutrino NSI.

Jet substructure probe to unfold singlet-doublet dark matter in the presence of non-standard cosmology

We examine the singlet-doublet fermionic dark matter model, where the non-thermal production of the dark matter in light of a non-standard cosmology demands a significantly large interaction rate than the typical radiation-dominated Universe. Despite being a model of freeze-in light dark matter and heavy mediator, the characteristic long-lived particle searches at the collider experiment and the displaced vertex signature do not help in probing such a dark sector since this non-standard interaction mandates nearly prompt decay. We make a counterproposal to probe such signal with di-fat-jets generated from the boosted decays of massive vector bosons and Standard Model Higgs, along with the substantial missing transverse momentum to probe the dark matter at LHC. Interestingly, substructure variables associated with these fat jets have an additional handle to tackle the extensive QCD background as it encodes implicit footmarks of their origin. We adopt the multivariate analysis with the booted decision tree to constrain the measured relic density allowed parameter space of dark matter in the presence of the modified cosmological scenario. Our study shows how the non-trivial expansion affects dark matter production in the early Universe and alters the required search strategies at colliders. This probe provides the best discovery prospect at the HL-LHC for extended parameter space now opened up in the dark sector.

Constraining flavor-universal nonstandard interactions and the superweak extension of the standard model

Constraining flavor-universal nonstandard interactions and the superweak extension of the standard model

Search for exotic interactions of solar neutrinos in the CDEX-10 experiment

We investigate exotic neutrino interactions using the 205.4−kg·day dataset from the CDEX-10 experiment at the China Jinping Underground Laboratory. New constraints on the mass and couplings of new gauge bosons are presented. Two nonstandard neutrino interactions are considered: a U(1)B–L gauge-boson-induced interaction between an active neutrino and electron/nucleus, and a dark-photon-induced interaction between a sterile neutrino and electron/nucleus via kinetic mixing with a photon. This work probes an unexplored parameter space involving sterile neutrino coupling with a dark photon. New laboratory limits are derived on dark photon masses below 1 eV/c2 at some benchmark values of Δm412 and g′2sin22θ14.Received 21 October 2022Revised 22 November 2022Accepted 17 May 2023DOI:https://doi.org/10.1103/PhysRevD.107.112002Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasExtensions of gauge sectorParticle astrophysicsParticle interactionsParticle mixing & oscillationsSolar neutrinosPhysical SystemsHypothetical gauge bosonsNeutrinosSterile neutrinosTechniquesDark matter detectorsNeutrino detectorsSolid-state detectorsParticles & FieldsGravitation, Cosmology & Astrophysics

Light curves of BSM-induced neutrino echoes in the optically thin limit

High-energy neutrinos from astrophysical transients serve as a probe of neutrino physics beyond the Standard Model. In particular, nonstandard interaction of neutrinos with the cosmic neutrino background or dark matter (DM) may have imprints on not only their spectra but also the arrival and time-delay distributions. Assuming that the interaction occurs at most once during the neutrino propagation, we provide general analytic formulas for light curves of the neutrino echoes induced by BSM. The formulas can be used for constraining neutrino-neutrino scattering, neutrino-DM scattering, and other scattering processes experienced by relativistic particles.

Discriminating between Lorentz violation and non-standard interactions using core-passing atmospheric neutrinos at INO-ICAL

Precision measurements of neutrino oscillation parameters have provided a tremendous boost to the search for sub-leading effects due to several beyond the Standard Model scenarios in neutrino oscillation experiments. Among these, two of the well-studied scenarios are Lorentz violation (LV) and non-standard interactions (NSI), both of which can affect neutrino oscillations significantly. We point out that, at a long-baseline experiment where the neutrino oscillation probabilities can be well-approximated by using the line-averaged constant matter density, the effects of these two scenarios can mimic each other. This would allow the limits obtained at such an experiment on one of the above scenarios to be directly translated to the limits on the other scenario. However, for the same reason, it would be difficult to distinguish between LV and NSI at a long-baseline experiment. We show that the observations of atmospheric neutrinos, which travel a wide range of baselines and may encounter sharp density changes at the core-mantle boundary, can break this degeneracy. We observe that identifying neutrinos and antineutrinos separately, as can be done at INO-ICAL, can enhance the capability of atmospheric neutrino experiments to discriminate between these two new-physics scenarios.