Neutrino Magnetic Dipole Moment Research Articles

Extra dimensions with light and heavy neutral leptons: an application to CEνNS

We explore the possibility of relating extra dimensions with light and heavy Dirac-type neutral leptons and develop a framework for testing them in various laboratory experiments. The Kaluza-Klein modes in the large extra dimension models of the light neutral leptons could mix with the standard model neutrinos and produce observable effects in the oscillation experiments. We show that the chirality flipping up-scattering processes occurring through either neutrino magnetic dipole moment or the weakly coupled scalar interactions can also produce heavy Kaluza-Klein modes of the corresponding right-handed neutral leptons propagating in one or more extra dimensions. However, to conserve the four- dimensional energy-momentum, their masses must be below the maximum energy of the neutrinos in the initial state. The appreciable size of extra dimensions connected with these heavy neutral leptons can thus affect the cross-sections of these processes. This framework applies to any up-scattering process. Our work here focuses only on its application to the coherent elastic neutrino-nucleus scattering process. We derive constraints on the size of extra dimensions using the COHERENT data in oscillation and up-scattering processes. For model with one large extra dimension for the light neutral leptons, we obtain the limits, R ~ 3 μm (NH) and R ~ 2.5 μm (IH), on the size of extra dimension corresponding to the absolute mass limit, m0 ≤ 3 × 10−3 eV at 90% C.L. from the short-baseline oscillations. Using the up-scattering process for heavy neutral leptons, we obtain new parameter spaces between the size of extra dimensions and parameters of the dipole or scalar interactions.

Sensitivity of direct detection experiments to neutrino magnetic dipole moments

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.

One-loop running of dimension-six Higgs-neutrino operators and implications of a large neutrino dipole moment

We compute the one-loop running of the dimension-six CP-even Higgs operators in the Standard Model effective field theory involving the right-handed component of the would-be Dirac neutrinos. Then, on the basis of naturalness arguments, for some operators we obtain bounds that surpass direct constraints by orders of magnitude. We also discuss the implications of a large Dirac neutrino magnetic dipole moment. In particular, we demonstrate that a neutrino magnetic moment explaining the recent XENON1T excess induces Higgs and Z invisible decays with branching ratios in the range [10−18, 10−12]. These numbers are unfortunately beyond the reach of current and near future facilities.

Computational mathematics applied to astrophysics: Three cases of study

The role of computational mathematics on the study of the fundamental properties of neutrinos and axions and their impact on the energy loss within stellar structure is illustrated in this work. The theoretical predictions, done with the aid of a numerical code for simulating stellar evolution, are used in three cases of interest: the number of neutrinos reaching our planet from the closest stellar system, calculated by modelling its two main stars and their corresponding neutrino spectrum; the magnitude of the neutrino magnetic dipole moment and the axion-electron coupling constant is estimated by comparing stellar models to the tip-RGB of fifty globular clusters; and, finally, the survival of the Earth, after the Sun becomes a red giant is tested for an scenario in which axions and neutrinos are being simultaneously produced within the solar core.

Coherent scattering and macroscopic coherence: implications for neutrino, dark matter and axion detection

We study the question of whether coherent neutrino scattering can occur on macroscopic scales, leading to a significant increase of the detection cross section. We concentrate on radiative neutrino scattering on atomic electrons (or on free electrons in a conductor). Such processes can be coherent provided that the net electron recoil momentum, i.e. the momentum transfer from the neutrino minus the momentum of the emitted photon, is sufficiently small. The radiative processes is an attractive possibility as the energy of the emitted photons can be as large as the momentum transfer to the electron system and therefore the problem of detecting extremely low energy recoils can be avoided. The requirement of macroscopic coherence severely constrains the phase space available for the scattered particle and the emitted photon. We show that in the case of the scattering mediated by the usual weak neutral current and charged current interactions this leads to a strong suppression of the elementary cross sections and therefore the requirement of macroscopic coherence results in a reduction rather than an increase of the total detection cross section. However, for the νe scattering mediated by neutrino magnetic or electric dipole moments coherence effects can actually increase the detection rates. Effects of macroscopic coherence can also allow detection of neutrinos in 100 eV — a few keV energy range, which is currently not accessible to the experiment. A similar coherent enhancement mechanism can work for relativistic particles in the dark sector, but not for the conventionally considered non-relativistic dark matter.

Phenomenology of the new physics coming from 2HDMs to the neutrino magnetic dipole moment

In several frameworks for leptons sectors of Two Higgs Doublet Models, we calculate the magnetic dipole moment for different flavor types of neutrino. Computations are carried out by assuming a normal hierarchy for neutrino masses, and analyzing the process [Formula: see text] with a charged Higgs boson into the loop. The analysis was performed by sweeping the charged Higgs mass and taking into account the experimental constraints for relevant parameters in Two Higgs Doublet Models with and without flavor changing neutral currents; obtaining magnetic dipole moments close to the experimental thresholds for tau neutrinos in type II and lepton-specific cases. In the neutrino-specific scenario, the contribution of new physics could be sizeable to the current measurement for flavor magnetic dipole moment. This fact leads to excluding possible zones in the parameter space of charged Higgs mass and vacuum expectation value of the second doublet.

Implications of a primordial magnetic field for magnetic monopoles, axions, and Dirac neutrinos

We explore some particle physics implications of the growing evidence for a helical primordial magnetic field (PMF). From the interactions of magnetic monopoles and the PMF, we derive an upper bound on the monopole number density, $n(t_0) < 1 \times 10^{-20}~{\rm cm}^{-3}$, which is a "primordial" analog of the Parker bound for the survival of galactic magnetic fields. Our bound is weaker than existing constraints, but it is derived under independent assumptions. We also show how improved measurements of the PMF at different redshifts can lead to further constraints on magnetic monopoles. Axions interact with the PMF due to the $\varphi {\bf E}\cdot {\bf B}$ interaction. Including the effects of the cosmological plasma, we find that the helicity of the PMF is a source for the axion field. Although the magnitude of the source is small for the PMF, it could potentially be of interest in astrophysical environments. Finally we apply constraints on the neutrino magnetic dipole moment that arise from requiring successful big bang nucleosynthesis in the presence of a PMF, and using the suggested strength $\sim 10^{-14}~{\rm G}$ and coherence length $\sim 10~{\rm Mpc}$ we find $\mu_\nu \lesssim 10^{-16} \mu_B$.

Gauged Unparticles Contribution to the Neutrino Anomalous Dipole Moment

A one loop gauged unparticles contribution to the anomalous neutrino magnetic and electric dipole moments is presented and a prescription is proposed.

Constraining the neutrino magnetic dipole moment from white dwarf pulsations

Pulsating white dwarf stars can be used as astrophysical laboratories to constrain the properties of weakly interacting particles. Comparing the cooling rates of these stars with the expected values from theoretical models allows us to search for additional sources of cooling due to the emission of axions, neutralinos, or neutrinos with magnetic dipole moment. In this work, we derive an upper bound to the neutrino magnetic dipole moment (μν) using an estimate of the rate of period change of the pulsating DB white dwarf star PG 1351+489. We employ state-of-the-art evolutionary and pulsational codes which allow us to perform a detailed asteroseismological period fit based on fully DB white dwarf evolutionary sequences. Plasmon neutrino emission is the dominant cooling mechanism for this class of hot pulsating white dwarfs, and so it is the main contributor to the rate of change of period with time () for the DBV class. Thus, the inclusion of an anomalous neutrino emission through a non-vanishing magnetic dipole moment in these sequences notably influences the evolutionary timescales, and also the expected pulsational properties of the DBV stars. By comparing the theoretical value with the rate of change of period with time of PG 1351+489, we assess the possible existence of additional cooling by neutrinos with magnetic dipole moment. Our models suggest the existence of some additional cooling in this pulsating DB white dwarf, consistent with a non-zero magnetic dipole moment with an upper limit of μν ≲ 10-11 μB. This bound is somewhat less restrictive than, but still compatible with, other limits inferred from the white dwarf luminosity function or from the color-magnitude diagram of the Globular cluster M5. Further improvements of the measurement of the rate of period change of the dominant pulsation mode of PG 1351+489 will be necessary to confirm our bound.

Limits on the neutrino magnetic dipole moment from the luminosity function of hot white dwarfs

Recent determinations of the white dwarf luminosity function (WDLF) from very large surveys have extended our knowledge of the WDLF to very high luminosities. This, together with the availability of new full evolutionary white dwarf models that are reliable at high luminosities, have opened the possibility of testing particle emission in the core of very hot white dwarfs, where neutrino processes are dominant. We use the available WDLFs from the Sloan Digital Sky Survey and the SuperCOSMOS Sky Survey to constrain the value of the neutrino magnetic dipole moment ($\mu_\nu$). We constructed theoretical WDLFs for different values of $\mu_\nu$ and performed a $\chi^2$-test to derive constraints on the value of $\mu_\nu$. We also constructed a unified WDLF by averaging the SDSS and SSS and estimated the uncertainties by taking into account the differences between the WDLF at each magnitude bin. Then we compared all WDLFs with theoretical WDLFs.Comparison between theoretical WDLFs and both the SDSS and the averaged WDLF indicates that $\mu_\nu$ should be $\mu_\nu<5\times 10^{-12}\, e\hbar/(2m_e c)$. In particular, a $\chi^2$-test on the averaged WDLF suggests that observations of the disk WDLF exclude values of $\mu_\nu>5\times 10^{-12}e\hbar/(2m_e c)$ at more than a 95\% confidence level, even when conservative estimates of the uncertainties are adopted. Our study shows that modern WDLFs, which extend to the high-luminosity regime, are an excellent tool for constraining the emission of particles in the core of hot white dwarfs. However, discrepancies between different WDLFs suggest there might be some relevant unaccounted systematic errors. A larger set of completely independent WDLFs, as well as more detailed studies of the theoretical WDLFs and their own uncertainties, is desirable to explore the systematic uncertainties behind this constraint.

Particle-physics constraints from the globular cluster M5: neutrino dipole moments

Stellar evolution is modified if energy is lost in a "dark channel" similar to neutrino emission. Comparing modified stellar evolution sequences with observations provides some of the most restrictive limits on axions and other hypothetical low-mass particles and on non-standard neutrino properties. In particular, a putative neutrino magnetic dipole moment mu_nu enhances the plasmon decay process, postpones helium ignition in low-mass stars, and therefore extends the red-giant branch (RGB) in globular clusters (GCs). The brightness of the tip of the RGB (TRGB) remains the most sensitive probe for mu_nu and we revisit this argument from a modern perspective. Based on a large set of archival observations, we provide high-precision photometry for the Galactic GC M5 (NGC5904) and carefully determine its TRGB position. On the theoretical side, we add the extra plasmon decay rate brought about by mu_nu to the Princeton-Goddard-PUC stellar evolution code. Different sources of uncertainty are critically examined. The main source of systematic uncertainty is the bolometric correction and the main statistical uncertainty derives from the distance modulus based on main-sequence fitting. (Other measures of distance, e.g., the brightness of RR Lyrae stars, are influenced by the energy loss that we wish to constrain.) The statistical uncertainty of the TRGB position relative to the brightest RGB star is less important because the RGB is well populated. We infer an absolute I-band brightness of M_I=-4.17+/-0.13 mag for the TRGB compared with the theoretical prediction of -3.99+/-0.07 mag, in reasonable agreement with each other. A significant brightness increase caused by neutrino dipole moments is constrained such that mu_nu<2.6x10^-12mu_B(68% CL), where mu_B is the Bohr magneton, and mu_nu<4.5x10^-12 mu_B(95% CL). In these results, statistical and systematic errors have been combined in quadrature.

Magnetic moment of the majorana neutrino in the left-right symmetric model

Corrections to the neutrino magnetic dipole moment from the singly charged Higgs bosons h(±) and \(\tilde \delta ^{\left( \pm \right)}\) were calculated within the left-right symmetric model involving Majorana neutrinos. It is shown that, if the h(±) and \(\tilde \delta ^{\left( \pm \right)}\) bosons lie at the electroweak scale, the contributions from Higgs sector are commensurate with the contribution of charged gauge bosons or may even exceed it. The behavior of the neutrino flux inmatter and in amagnetic field was studied. It was found that resonance transitions between light and heavy neutrinos are forbidden.

Dirac Neutrino Masses from Generalized Supersymmetry Breaking

We demonstrate that Dirac neutrino masses in the experimentally preferred range are generated within supersymmetric gauge extensions of the standard model with a generalized supersymmetry breaking sector. If the superpotential neutrino Yukawa terms are forbidden by the gauge symmetry [such as a U(1)'], sub-eV scale effective Dirac mass terms can arise at tree level from hard supersymmetry breaking Yukawa couplings, or at one loop due to nonanalytic soft supersymmetry breaking trilinear scalar couplings. The radiative neutrino magnetic and electric dipole moments vanish at one-loop order.

C-caronerenkov Radiation by Neutrinos in a Supernova Core.

Neutrinos with a magnetic dipole moment propagating in a medium with a velocity larger than the phase velocity of light emit photons by the Cerenkov process. The Cerenkov radiation is a helicity flip process via which a left-handed neutrino in a supernova core may change into a sterile right-handed one and free-stream out of the core. Assuming that the luminosity of such sterile right-handed neutrinos is less than $10^{53}$ ergs/sec gives an upper bound on the neutrino magnetic dipole moment $\mu_\nu < 0.2 \times 10^{-13} \mu_B$. This is two orders of magnitude more stringent than the previously established bounds on $\mu_\nu$ from considerations of supernova cooling rate by right-handed neutrinos.

Neutrino magnetic moment and neutron star cooling.

The effects of a finite neutrino magnetic dipole moment on the cooling of neutron stars are studied. It is shown that a finite magnetic moment ([mu][sub [nu]]) of the order of 10[sup [minus]10] in units of the Bohr magneton ([mu][sub [ital B]]) would modify the standard cooling curve of neutron stars for a period of 10--10[sup 3] yr after their birth, which demonstrates how crust cooling could compete with core cooling within the typical time scale for thermal conduction from the core to the surface. The consistency with the current observational data gives a limit [mu][sub [nu]][lt]5[times]10[sup [minus]7][mu][sub [ital B]] and possible improvements of this value in the future are discussed.

Effects of scalar exchange and neutrino magnetic and electric dipole moments in [formula omitted] scattering

We consider elastic ν e e − scattering where ν e is a Dirac neutrino furnished with a magnetic and/or electric dipole moment. The effects of additional scalar interactions are analysed with emphasis on the interference of scalar and electromagnetic amplitudes and a possible azimuthal asymmetry in the scattering of the solar neutrino flux.

Standard and nonstandard plasma neutrino emission revisited

view Abstract Citations (185) References (22) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Standard and Nonstandard Plasma Neutrino Emission Revisited Haft, Martin ; Raffelt, Georg ; Weiss, Achim Abstract On the basis of Braaten and Segel's representation of the electromagnetic dispersion relations in a QED plasma we check the numerical accuracy of several published analytic approximations to the plasma neutrino emission rates. As we find none of them satisfactory we derive a new analytic approximation which is accurate to within 4\%\ where the plasma process dominates. The correct emission rates in the parameter regime relevant for the red giant branch in globular clusters are larger by about $10-20$\% than those of previous stellar evolution calculations. Therefore, the core mass of red giants at the He flash is larger by about $0.005\M_\odot$ or 1\% than previously thought. Our bounds on neutrino magnetic dipole moments remain virtually unchanged. Publication: The Astrophysical Journal Pub Date: April 1994 DOI: 10.1086/173978 arXiv: arXiv:astro-ph/9309014 Bibcode: 1994ApJ...425..222H Keywords: Computational Astrophysics; Emission Spectra; Magnetic Dispersion; Neutrinos; Numerical Analysis; Plasmas (Physics); Quantum Electrodynamics; Approximation; Magnetic Dipoles; Stellar Cores; Stellar Evolution; Astrophysics; ELEMENTARY PARTICLES; PLASMAS; RADIATION MECHANISMS: MISCELLANEOUS; STARS: GIANTS; STARS: INTERIORS; Astrophysics E-Print: LaTeX, 16 pages, 12 figures on request from authors, MPI-Ph/93-65 full text sources arXiv | ADS | Related Materials (1) Erratum: 1995ApJ...438.1017H

Intrinsic neutrino properties

We discuss neutrino massand consider two processes, neutrinoless double beta decay and ν → ν oscillation, whose observation would show that neutrinos are their own antiparticles and also that they have mass. We then focus on neutrino magnetic and electric dipole moments. After discussing the laboratory and astrophysical bounds on such moments, we describe ways in which they could influence the behavior of solar neutrinos, and discuss theoretical models which allow them to be large enough to do so.

Mechanism for large neutrino magnetic moments.

A general mechanism, based on very simple considerations of spin, is proposed, which has the effect of enhancing the neutrino magnetic dipole moment relative to the neutrino mass.

Magnetically induced neutrino oscillations and neutrino refractive effects in the early Universe.

The interrelation between hypothetical neutrino magnetic dipole moments (MDMs) and primeval magnetic fields is discussed. The parameter range over which these possibilities are mutually exclusive is determined, taking into account for the first time neutrino refractive effects in the early universe. It is shown that an independent determination of either the neutrino MDMs or the primeval magnetic field strength would set powerful bounds on the other quantity.