Neutrino Electromagnetic Properties Research Articles

Disentangle neutrino electromagnetic properties with atomic radiative pair emission

We elaborate the possibility of using the atomic radiative emission of neutrino pair (RENP) to probe the neutrino electromagnetic properties, including magnetic and electric dipole moments, charge radius, and anapole. With the typical O\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{O} $$\\end{document}(eV) momentum transfer, the atomic RENP is sensitive to not just the tiny neutrino masses but also very light mediators to which the massless photon belongs. The neutrino EM properties introduce extra contribution besides the SM one induced by the heavy W/Z gauge bosons. Since the associated photon spectrum is divided into several sections whose boundaries are determined by the final-state neutrino masses, it is possible to identify the individual neutrino EM form factor elements. Most importantly, scanning the photon spectrum inside the particular section with deviation from the SM prediction once observed allows identification of the neutrino EM form factor type. The RENP provides an ultimate way of disentangling the neutrino EM properties to go beyond the current experimental searches or observations.

Testing neutrino electromagnetic properties at current and future dark matter experiments

Testing neutrino electromagnetic properties at current and future dark matter experiments

Elastic Neutrino–Atom Scattering as a Probe of Neutrino Millicharge and Magnetic Moment

Neutrino scattering on a target at low-energy transfer is one of the basic tools for searching for neutrino electromagnetic properties. We consider the effects of the neutrino millicharge and magnetic moment on the atomic recoil spectrum in elastic neutrino–atom scattering. The results of our calculations of differential cross sections for elastic collisions of tritium neutrinos with the H, 2H, 3He, and 4He atomic targets show that the corresponding experiments can achieve sensitivity to the indicated neutrino electromagnetic characteristics by orders of magnitude better than the available measurements of elastic neutrino–electron and neutrino–nucleus collisions.

Physics implications of a combined analysis of COHERENT CsI and LAr data

The observation of coherent elastic neutrino nucleus scattering has opened the window to many physics opportunities. This process has been measured by the COHERENT Collaboration using two different targets, first CsI and then argon. Recently, the COHERENT Collaboration has updated the CsI data analysis with a higher statistics and an improved understanding of systematics. Here we perform a detailed statistical analysis of the full CsI data and combine it with the previous argon result. We discuss a vast array of implications, from tests of the Standard Model to new physics probes. In our analyses we take into account experimental uncertainties associated to the efficiency as well as the timing distribution of neutrino fluxes, making our results rather robust. In particular, we update previous measurements of the weak mixing angle and the neutron root mean square charge radius for CsI and argon. We also update the constraints on new physics scenarios including neutrino nonstandard interactions and the most general case of neutrino generalized interactions, as well as the possibility of light mediators. Finally, constraints on neutrino electromagnetic properties are also examined, including the conversion to sterile neutrino states. In many cases, the inclusion of the recent CsI data leads to a dramatic improvement of bounds.

Neutrino millicharge and other electromagnetic interactions with COHERENT-2021 data

We analyze new data from the COHERENT experiment of the coherent neutrino-nucleus scattering to investigate the electromagnetic interactions of neutrinos. With almost double the statistics and precision now, the statistical significance of the observed process has now enhanced to 11.6σ. We derive constraints on the electromagnetic properties of neutrinos using the new COHERENT data. The constraints improve by more than a factor of two compared to the previous bounds. Furthermore, we discuss the unique behavior of the neutrino millicharge at lower energy recoils and show its unique dependence on its interference with the standard model contribution, inverse power of recoil energy and the mass of the target particle in comparison to the other interactions.

Using DUNE to shed light on the electromagnetic properties of neutrinos

We study future DUNE sensitivity to various electromagnetic couplings of neutrinos, including magnetic moments, milli-charges, and charge radii. The DUNE PRISM capabilities play a crucial role in constraining the electron flavored couplings. We find that DUNE will be able to place the strongest beam based constraint on the muon-neutrino magnetic moment by improving on LSND’s bounds by roughly a factor of two, although Borexino’s constraint from solar neutrinos will be stronger. For the muon neutrino millicharge DUNE can place the leading beam based bound, with two orders of magnitude improvement compared to the existing COHERENT constraint, suggesting that DUNE can be useful for light mediators more generally. Despite this strength, the millicharge bounds are not competitive with strong bounds from stellar cooling, beta-decay, and matter stability. Finally, DUNE may be able to test the SM prediction for the muon neutrino charge radius, by placing a constraint two times better than CHARM-II and CCFR experiments.

Impact of the Dresden-II and COHERENT neutrino scattering data on neutrino electromagnetic properties and electroweak physics

Coherent elastic neutrino-nucleus scattering (CEνNS) represents a powerful tool to investigate key electroweak physics parameters and neutrino properties since its first observation in 2017 by the COHERENT experiment exploiting the spallation neutron source at Oak Ridge National Laboratory. In light of the recent detection of such a process with antineutrinos produced by the Dresden-II reactor scattering off a germanium detector, we revisit the limits so far set on the neutrino magnetic moments, charge radii and millicharges as well as on the weak mixing angle. In order to do so, we also include the contribution of elastic neutrino-electron scattering, whose effect becomes non negligible in some beyond the Standard Model theories. By using different hypotheses for the germanium quenching factor and the reactor antineutrino flux, we provide a measurement of the weak mixing angle at the low-energy scale of the Dresden-II reactor experiment and, thanks to a combined analysis with the latest cesium iodide and argon data set released by the COHERENT Collaboration, we deliver updated limits for the neutrino electromagnetic properties. Interestingly, we are able to set a new best upper limit on the electron neutrino charge radius and significantly improve the other CEνNS-related limits on the neutrino electric charge and magnetic moment.

First upper limits on neutrino electromagnetic properties from the CONUS experiment

We report first constraints on electromagnetic properties of neutrinos from neutrino-electron scattering using data obtained from the CONUS germanium detectors, i.e. an upper limit on the effective neutrino magnetic moment and an upper limit on the effective neutrino millicharge. The electron antineutrinos are emitted from the 3.9 hbox {GW}_mathrm {th} reactor core of the Brokdorf Nuclear Power Plant in Germany. The CONUS low-background detectors are positioned at a distance of 17.1 m from the reactor core center. The analyzed data set includes 689.1 kg d collected during reactor ON periods and 131.0 kg d collected during reactor OFF periods in the energy range of . With the current statistics, we are able to determine an upper limit on the effective neutrino magnetic moment of mu _nu < 7.5cdot 10^{-11},mu _B at 90% confidence level. No neutrino signal in this channel or in the CEnu NS channel has been observed at a nuclear power plant so far. From this first magnetic moment limit we can derive an upper bound on the neutrino millicharge of vert {q}_{nu }vert < 3.3cdot 10^{-12},e_0.

Scattering of low energy neutrinos and antineutrinos by atomic electrons

Studies of neutrino mixing and oscillations, solar neutrinos as background in dark matter searches involving electron detection, detection of sterile neutrino warm dark matter, and of possible electromagnetic properties of neutrinos, have generated interest in the low energy O(10 keV) scattering of electron neutrinos and antineutrinos by atomic electrons where the binding of the atomic electron cannot be ignored. Of particular interest is the ionization of atoms by neutrinos and antineutrinos. Most existing calculations are based on modifications of the free electron differential cross section, which destroy the relationship between the neutrino helicities and the orbital and spin angular momenta of the atomic electrons. The present calculations maintain the full collision dynamics by formulating the scattering in configuration space using the Bound Interaction Picture, rather than the usual formulation in the Interaction Picture in momentum space as appropriate to scattering by free electrons. Energy spectra of ionization electrons produced by scattering of neutrinos and antineutrinos with energies of 5, 10, 20, and 30 keV by hydrogen, helium and neon have been calculated using Dirac central field eigenfunctions and are presented as ratios to the spectra for scattering by free electrons. Binding effects increase strongly with atomic number, are largest for low neutrino energy and, for each neutrino energy, greatest at the high electron energy end of the spectrum. The most extreme effects of binding are for 5 keV scattering by Ne where the ratios are less than 0.1. The energy spectra are calculated for both a Coulombic final electron state and a free final electron state. The results indicate that the binding effects from the continuum state of the final electron are significant and can be comparable to those arising from the bound initial electron state.

Electromagnetic neutrino: The basic processes and astrophysical probes

After a brief reminder on the electromagnetic properties of neutrinos, the main processes of the electromagnetic interactions of neutrinos in astrophysics and the corresponding limitations on millicharges and effective magnetic moments of the particle are discussed.

Neutrino magnetic moments in low-energy neutrino scattering on condensed matter systems

The cross sections of elastic neutrino scattering on electrons and nuclei in the regime of low-energy transfer are known to be very sensitive to neutrino electromagnetic properties. In particular, the magnetic moment of the neutrino can be effectively searched using liquid or solid detectors with a very low energy threshold. We present the formalism that incorporates the neutrino magnetic moment contribution in the theoretical treatment of the low-energy elastic neutrino scattering on a condensed-matter target. The concept of the dynamic structure factor is employed to describe the collective effects in the target. The differential cross section for tritium antineutrino scattering on the superfluid 4He is calculated numerically. We find that the neutrino magnetic moment of the order of 10−11 μB strongly affects the cross section. Our results can be used in the search of neutrino magnetic moments in future low-energy neutrino scattering experiments with liquid or solid targets.

The Electromagnetic Properties of the Neutrino as a Window to New Physics

An overview of the problem of the neutrino electromagnetic properties along with the contributions of the neutrino physics research group of Moscow State University to the investigation of this problem is presented.

Electromagnetic neutrinos: New constraints and new effects in oscillations

A short overview of neutrino electromagnetic properties with focus on existed experimental constraints and future prospects is presented. The related new effect in neutrino flavour and spin-flavour oscillations in the transversal matter currents is introduced.

Studies of neutrino interactions at the Kuo-Sheng Neutrino Laboratory with sub-keV Ge-detectors

Germanium detectors with point contact configuration is an exciting detector technology which provides sub-keV sensitivities as low as 100 eVee with kg-scale detector mass. This detector technique offers a unique opportunity to realize experiments on dark matter, to enhance the sensitivity of electromagnetic properties of neutrino and coherent elastic scattering of neutrino nucleus with reactor neutrino source. The TEXONO collaboration have been pursuing this research program at the Kuo-Sheng Neutrino Laboratory (KSNL) in Taiwan. We will highlight our results on neutrino electromagnetic properties, search of sterile neutrinos, as well as studies towards observation of neutrino-nucleus coherent scattering. The detector R&D programs which allow us to experimentally probe this new energy window will be discussed. The efforts set the stage and complement the CDEX dark matter experiment at the new China Jinping Underground Laboratory (CJPL) in China.

Overview on neutrino electromagnetic properties

There is a short overview on the selected issues of neutrino electromagnetic properties with focus on existed experimental constraints and on the effect of neutrino spin precession in the transversal magnetic field and transversal matter current.

Constraining new physics from the first observation of coherent elastic neutrino-nucleus scattering

The process of neutral-current coherent elastic neutrino-nucleus scattering, consistent with the Standard Model (SM) expectation, has been recently measured by the COHERENT experiment at the Spallation Neutron Source. On the basis of the observed signal and our nuclear calculations for the relevant Cs and I isotopes, the extracted constraints on both conventional and exotic neutrino physics are updated. The present study concentrates on various SM extensions involving vector and tensor nonstandard interactions as well as neutrino electromagnetic properties, with an emphasis on the neutrino magnetic moment and the neutrino charge radius. Furthermore, models addressing a light sterile neutrino state are examined, and the corresponding regions excluded by the COHERENT experiment are presented.

On the Properties of Neutrinos

This article reviews our present understanding of neutrino properties with a particular emphasis on observable differences between Majorana and Dirac neutrinos. We summarize current and future experimental efforts toward measuring neutrino properties and describe consequences of the Majorana versus Dirac nature of neutrinos on neutrino masses, neutrino decays, and neutrino electromagnetic properties.

Neutrino propagation in an electron background with an inhomogeneous magnetic field

We study the electromagnetic coupling of a neutrino that propagates in a two-stream electron background medium. Specifically, we calculate the electromagnetic vertex function for a medium that consists of a normal electron background plus another electron stream background that is moving with a velocity four-vector v^mu relative to the normal background. The results can be used as the basis for studying the neutrino electromagnetic properties and various processes in such a medium. As an application, we calculate the neutrino dispersion relation in the presence of an external magnetic field (mathbf {B}), focused in the case in which B is inhomogeneous, keeping only the terms of the lowest order in 1/m^2_W and linear in the B and its gradient. We show that the dispersion relation contains additional anisotropic terms involving the derivatives of mathbf {B}, such as the gradient of {hat{k}}cdot (mathbf {v}times mathbf {B}), which involve the stream background velocity, and a term of the form {hat{k}}cdot (nabla times mathbf {B}) that can be present in the absence of the stream background, in addition to a term of the form {hat{k}}cdot mathbf {v} and the well known term {hat{k}}cdot mathbf {B} that arises in the constant mathbf {B} case. The derivative-dependent terms are even under a CP transformation. As a result, in contrast to the latter two just mentioned, they depend on the sum of the particle and antiparticle densities and therefore can be non-zero in a CP-symmetric medium in which the particle and antiparticle densities are equal.

COHERENT constraints to conventional and exotic neutrino physics

The process of neutral-current coherent elastic neutrino-nucleus scattering, consistent with the Standard Model (SM) expectation, has been recently measured by the COHERENT experiment at the Spallation Neutron Source. On the basis of the observed signal and our nuclear calculations for the relevant Cs and I isotopes, the extracted constraints on both conventional and exotic neutrino physics are updated. The present study concentrates on various SM extensions involving vector and tensor nonstandard interactions as well as neutrino electromagnetic properties, with an emphasis on the neutrino magnetic moment and the neutrino charge radius. Furthermore, models addressing a light sterile neutrino state and scenarios with new propagator fields---such as vector $Z^\prime$ and scalar bosons---are examined, and the corresponding regions excluded by the COHERENT experiment are presented.

Neutrino-atom collisions

Neutrino-atom scattering provides a sensitive tool for probing nonstandard interactions of massive neutrinos in laboratory measurements. The ionization channel of this collision process plays an important role in experiments searching for neutrino magnetic moments. We discuss some theoretical aspects of atomic ionization by massive neutrinos. We also outline possible manifestations of neutrino electromagnetic properties in coherent elastic neutrino-nucleus scattering.