Antineutrino Pairs Research Articles

Practical Dirac Majorana confusion theorem: issues and applicability

We inspect the model-independent study of practical Dirac Majorana confusion theorem (pDMCT) – a wide spread belief that the difference between Dirac and Majorana neutrinos via any kinematical observable would be practically impossible to determine because of the difference only being proportional to the square of neutrino mass – in context of processes that have at least a neutrino antineutrino pair in their final state. We scrutinize the domain of applicability of pDMCT and also highlight those aspects that are often misunderstood. We try to clarify some of the frequently used concepts that are used to assert pDMCT as a generic feature irrespective of the process, or observable, such as the existence of any analytic continuity between Dirac and Majorana neutrinos in the limit mν→0.\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$m_{\ u } \\rightarrow 0.$$\\end{document} In summary, we illustrate that pDMCT is not any fundamental property of neutrinos, instead, it is a phenomenological feature of neutrino non-observation, depending on models and processes.

MeV, GeV and TeV Neutrinos from Binary-Driven Hypernovae

We analyze neutrino emission channels in energetic (≳1052 erg) long gamma-ray bursts within the binary-driven hypernova model. The binary-driven hypernova progenitor is a binary system composed of a carbon-oxygen star and a neutron star (NS) companion. The gravitational collapse leads to a type Ic supernova (SN) explosion and triggers an accretion process onto the NS. For orbital periods of a few minutes, the NS reaches the critical mass and forms a black hole (BH). Two physical situations produce MeV neutrinos. First, during the accretion, the NS surface emits neutrino–antineutrino pairs by thermal production. We calculate the properties of such a neutrino emission, including flavor evolution. Second, if the angular momentum of the SN ejecta is high enough, an accretion disk might form around the BH. The disk’s high density and temperature are ideal for MeV-neutrino production. We estimate the flavor evolution of electron and non-electron neutrinos and find that neutrino oscillation inside the disk leads to flavor equipartition. This effect reduces (compared to assuming frozen flavor content) the energy deposition rate of neutrino–antineutrino annihilation into electron–positron (e+e−) pairs in the BH vicinity. We then analyze the production of GeV-TeV neutrinos around the newborn black hole. The magnetic field surrounding the BH interacts with the BH gravitomagnetic field producing an electric field that leads to spontaneous e+e− pairs by vacuum breakdown. The e+e− plasma self-accelerates due to its internal pressure and engulfs protons during the expansion. The hadronic interaction of the protons in the expanding plasma with the ambient protons leads to neutrino emission via the decay chain of π-meson and μ-lepton, around and far from the black hole, along different directions. These neutrinos have energies in the GeV-TeV regime, and we calculate their spectrum and luminosity. We also outline the detection probability by some current and future neutrino detectors.

Physics Formalism Helmholtz Iyer Markoulakis Hamiltonian Mechanics Metrics towards Electromagnetic Gravitational Hilbert Coulomb Gauge String metrics

Iyer Markoulakis Helmholtz Hamiltonian metrics have been gauged to Coulombic Hilbert metrics, representing Gilbertian and Amperian natures of electromagnetic fields from mechanics of vortex rotational fields acting with gradient fields, typically in zero-point microblackhole general fields, extending to vacuum gravitational fields gauge. This ansatz general gaging helps to properly isolate field effects with physical analyses – mechanical, electric, magnetic components within the analytical processes. Vacuum gravitational fields and the flavor Higgs-Boson matter inertial gravitational fields have been thus quantified extending to stringmetrics constructs matrix showing charge asymmetry gauge metrics. Physical Analysis with applications to particle physics, Quantum ASTROPHYSICS, as well as grand unification physics have been advanced. Particle physics gauge matrix pointing to Dirac seas of electrons, monopoles with positrons, electron-positron annihilation leading to energy production, and the relativistic energy generating matter provided literature correlations. Quantum astrophysics extending gauge metrix analyzes of superluminal profile of signals velocity generating electron-positron chain like “curdling” action validates formalism with physics literature of electron-photon observed oscillatory fields configurations. Mechanism of creation of neutrino antineutrino pair orthogonal to electron positron “curdling” planes, that may lead to formation of protonic hydrogen of stars or orthogonally muon particles. These proposals will help to explain receding or fast expanding universe with the dark matter in terms of flavor metrics versus gauge associating metrics fields. Vacuum and gravitational monopoles, that are representation of compressed mass out of vortex Helmholtz decomposition fields have been interpolated to energy generation via electron positron monopole particles at cosmos extent of infinity

Evading the Grossman-Nir bound with \u2206I = 3/2 new physics

Rare kaon decays with missing energy, K → π+Emiss, have received considerable attention because their rates can be calculated quite precisely within the standard model (SM), where the missing energy is carried away by an undetected neutrino- antineutrino pair. Beyond the SM, clean theoretical predictions can also be made regarding these processes. One such prediction is the so-called Grossman-Nir (GN) bound, which states that the branching fractions of the KL and K+ modes must satisfy the relation mathrm{mathcal{B}}left({K}_Lto {pi}^0+{E}_{mathrm{miss}}right)underset{sim }{<}4.3mathrm{mathcal{B}}left({K}^{+}to {pi}^{+}+{E}_{mathrm{miss}}right) and applies within and beyond the SM, as long as the hadronic transitions change isospin by ∆I = 1/2. In this paper we extend the study of these modes to include new-physics scenarios where the missing energy is due to unobserved lepton-number-violating neutrino pairs, invisible light new scalars, or pairs of such scalars. The new interactions are assumed to arise above the electroweak scale and described by an effective field theory. We explore the possibility of violating the GN bound through ∆I = 3/2 contributions to the K → π transitions within these scenarios and find that large violations are only possible in the case where the missing energy is due to an invisible light new scalar.

Consequences of Massive Neutrino to Astrophysics and Cosmology

It is now recognized that a neutrino is a massive spin-1/2 particle. Consequently, neutrino- antineutrino pair production and their pair annihilation are theoretically valid processes. The data prove that the strength of weak interactions increases with collision energy. Therefore, a neutrino pair production event is expected to be a significant process in the region which is just outside the event horizon of a black hole. Another neutrino source is the pair production of particles like muons and charged pions whose decay produces neutrinos. Similarly, copious neutrino pair production events are expected to take place right after the big bang. Since a neutrino does not directly participate in electromagnetic interactions, its pair annihilation cannot directly produce photons. For this reason, a low energy neutrino-antineutrino collision can only go to another neutrino-antineutrino pair. It follows that the number of low energy neutrinos increases with time. This effect may contribute to the problem of the missing mass of the universe.

Tomography by neutrino pair beam

We consider tomography of the Earth's interior using the neutrino pair beam which has recently been proposed. The beam produces a large amount of neutrino and antineutrino pairs from the circulating partially stripped ions and provides the possibility to measure precisely the energy spectrum of neutrino oscillation probability together with a sufficiently large detector. It is shown that the pair beam gives a better sensitivity to probe the Earth's crust compared with the neutrino sources at present. In addition we present a method to reconstruct a matter density profile by means of the analytic formula of the oscillation probability in which the matter effect is included perturbatively to the second order.

Master integrals for double real radiation emission in heavy-to-light quark decay

We evaluate analytically the master integrals for double real radiation emission in the b rightarrow u W^* decay, where b and u are a massive and massless quark, respectively, while W^{*} is an off-shell charged weak boson. Since the W boson can subsequently decay in a lepton anti-neutrino pair, the results of the present paper constitute a further step toward a fully analytic computation of differential distributions for the semileptonic decay of a b quark at NNLO in QCD. The latter partonic process plays a crucial role in the study of inclusive semileptonic charmless decays of B mesons. Our results are expressed in terms of multiple polylogarithms of maximum weight four.

Initiating nuclear-chemical transformations in native systems: Phenomenology

A possible mechanism of nuclear transformations in biological systems in vivo is proposed. Reasons why there is no ionizing radiation that could be detrimental to native systems during the corresponding nuclear reactions are given. It is established that the initial stage of these processes is associated with that of ATP hydrolysis, which initiates the action of the inner-shell electron of an atom participating in the reaction on its nucleus according to the mechanism of weak nuclear interaction. This results in the formation of a nucleus in a metastable state with a disturbed nucleon structure and a charge one unit lower than that of the initial nucleus. It is also assumed that the atom participating in the reaction is adsorbed near the mouth of one of the transport ATPases in the cell’s cytoplasmic membrane, and the reason for the initiating impact the electron has on the nucleus is due to the emergence of a local electric field formed during ATP hydrolysis near the ion channel of a donor–acceptor pair of charges that is opposite to the direction of the average membrane field. It is concluded that as a result of the key role of weak nuclear interaction in these processes, the energy of nuclear transformations in biological systems in vivo is released through the emission of neutrino–antineutrino pairs that are harmless to living organisms.

Neutrino photoproduction on pseudo Nambu–Goldstone bosons

Production of single neutrinos as well as neutrino–antineutrino pairs by photons interacting with pseudo Nambu–Goldstone bosons is studied within the Standard Model. The corresponding cross sections are found analytically. The energy loss due to neutrino emission in a thermal plasma of photons and pions is calculated. It is shown that the obtained neutrino emissivity may be significantly enhanced in hot and dense matter due to in-medium modification of the pion decay constant. Phenomenological consequences for ultrarelativistic heavy-ion collisions and astrophysics are discussed.

FakingBs→μ+μ−

Recent evidence from observation of the flavor-changing neutral current decay B_s to mu+ mu- by the LHCb collaboration B(B_s to mu^+ mu^-) = (3.2 * 10^{-9}), is consistent with the latest standard model prediction B(B_s to mu^+ mu^-) = (3.23 +- 0.27) * 10^{-9}. While New Physics can still affect this decay amplitude, its contribution is certainly not the dominant one. We analyze branching ratios of the decays B_s to mu+ mu- X, with X = a photon or neutrino anti-neutrino pair, which can mimic B_s to mu+ mu- on portions of the parameter space where X is soft. We perform a model-independent standard model calculation of those processes incorporating heavy quark and chiral symmetries of QCD. We show that the considered contributions contribute to B_s to mu+ mu- at a sub-percent level.

General relativistic ray-tracing algorithm for the determination of the electron-positron energy deposition rate from neutrino pair annihilation around rotating neutron and quark stars

We present a full general relativistic numerical code for estimating the energy–momentum deposition rate (EMDR) from neutrino pair annihilation (⁠⁠). The source of the neutrinos is assumed to be a neutrino-cooled accretion disc around neutron and quark stars. We calculate the neutrino trajectories by using a ray-tracing algorithm with the general relativistic Hamilton's equations for neutrinos and derive the spatial distribution of the EMDR due to the annihilations of neutrinos and antineutrinos around rotating neutron and quark stars. We obtain the EMDR for several classes of rotating neutron stars, described by different equations of state of the neutron matter, and for quark stars, described by the Massachusetts Institute of Technology (MIT) bag model equation of state and in the colour–flavour-locked (CFL) phase. The distribution of the total annihilation rate of the neutrino–antineutrino pairs around rotating neutron and quark stars is studied for isothermal discs and accretion discs in thermodynamical equilibrium. We demonstrate both the differences in the equations of state for neutron and quark matter and rotation with the general relativistic effects significantly modify the EMDR of the electrons and positrons generated by the neutrino–antineutrino pair annihilation around compact stellar objects, as measured at infinity.

Hypothesis of Conservation of Particle Number

As for several nuclear reactions, the electroweak interaction is simply explained by a law of conservation of particle number. We find that the positron and electron consist of the three fundamental particles, and , respectively. Furthermore, the members of the second and third generations quark composites consist of the first generation quark and the neutrino of fundamental particles. The particle and its anti- particle pair(or neutrino and its antineutrino pair) have to be an energy quantum (or a photon). The minimum Higgs boson (called “God particle”) might be a neutral pion. The fundamental particles are simply up and down quark, neutrino, muon-neutrino, and those anti-particles.

Two-loop QCD corrections to the heavy-to-light quark decay

We present an analytic expression for the two-loop QCD corrections to the decay process b -> u W^*, where b and u are a massive and massless quark, respectively, while W^* is an off-shell charged weak boson. Since the W-boson can subsequently decay in a lepton anti-neutrino pair, the results of this paper are a first step towards a fully analytic computation of differential distributions for the semileptonic decay of a b-quark. The latter partonic process plays a crucial role in the study of inclusive semileptonic charmless decays of B-mesons. The three independent form factors characterizing the b W u vertex are provided in form of a Laurent series in (d-4), where d is the space-time dimension. The coefficients in the series are expressed in terms of Harmonic Polylogarithms of maximal weight 4, and are functions of the invariant mass of the leptonic decay products of the W-boson.

Monochromatic neutrino signals from dark matter annihilation

Dark matter (DM) annihilations in the Sun to neutrino–antineutrino pairs are known to have potentially observable signatures in neutrino telescopes such as IceCube and KM3. We propose a model independent analysis in which the monochomatic neutrino signal from dark matter (DM) annihilations in the Sun is related to the direct detection spin-independent and spin-dependent cross sections rather than assuming cross sections from a particular model. We propagate the neutrinos from the center of the Sun to the Earth taking into account matter effects on neutrino oscillations. For DM capture in the Sun via a large spin-dependent DM capture cross section the discovery prospects of the IceCube experiment are found to be promising.

The neutrino emission due to plasmon decay and neutrino luminosity of white dwarfs

One of the effective mechanisms of neutrino energy losses in red giants, pre‐supernovae and in the cores of white dwarfs is the emission of neutrino–antineutrino pairs in the process of plasmon decay. In this paper, we numerically calculate the emissivity due to plasmon decay in a wide range of temperatures 107–1011 K and densities (2 × 102–1014) g cm−3. Numerical results are approximated by convenient analytical expressions. We also calculate and approximate by analytical expressions the neutrino luminosity of white dwarfs due to plasmon decay, as a function of their mass and internal temperature. This neutrino luminosity depends on the chemical composition of white dwarfs only through the parameter μe (the net number of baryons per electron) and is the dominant neutrino luminosity in all white dwarfs at the neutrino cooling stage.

Neutrino–antineutrino pair production by a photon in a dense matter

The possibility of radiative effects that are due to interaction of fermions with a dense matter is investigated. Neutrino-antineutrino photo-production is studied. The rate of this process is calculated in the Furry picture. It is demonstrated that this effect does not disappear even if the medium refractive index is assumed to be equal to unity. The rate obtained strongly depends on the polarization states of the particles involved. This leads to evident spatial asymmetries, which may have certain consequences observable in astrophysical and cosmological studies.

Neutrino synchrotron radiation in electro-weak interaction

The neutrino synchrotron process has been considered within the framework of the electro-weak theory. An electron moving in a magnetic field with spiral path changes the Landau level to release the energy in terms of neutrino antineutrino pair. The calculation of scattering cross-section for the neutrino synchrotron radiation has been carried out. We also calculate the energy loss rate and compare our result with Landstreet’s result, graphically. Finally, the neutrino luminosity (expressed in the unit of solar luminosity) at different central temperatures of white dwarfs and neutron stars have been calculated to study the significance of this process in the later stages of the stellar evolution.

Parametric excitation of neutrino pairs by electron plasma waves

The collective coupling of neutrinos and anti-neutrinos in a dense plasma is considered. Such a coupling is provided by the existence of electron plasma waves. These waves can parametrically excite neutrino–anti-neutrino pairs, and the parametric decay rate is established. This stimulated process for neutrino pair production can eventually become dominant over the single particle decay rates characteristic of the usual Urca process and provide an alternative mechanism for the neutrino cooling of collapsing neutron stars.

Collective Urca Process

The collective coupling of neutrinos and anti-neutrinos in a degenerate dense plasma is considered. Such a coupling is provided by the existence of electron plasma waves, or plasmons. The electron plasma waves can decay into neutrino anti-neutrino pairs, and the collective decay rate is established, and shown to be dominant over the single particle decay rates characteristic of the usual Urca process.

ν-K0 ANALOGY, DIRAC–MAJORANA NEUTRINO DUALITY AND THE NEUTRINO OSCILLATIONS

The intent of this paper is to convey a new primary physical idea of a Dirac–Majorana neutrino duality in relation to the topical problem of neutrino oscillations. In view of the new atmospheric, solar and the LSND neutrino oscillation data, the Pontecorvo ν - K0 oscillation analogy is generalized to the notion of neutrino duality with substantially different physical meaning ascribed to the long-baseline and the short-baseline neutrino oscillations. At the level of CP-invariance, the suggestion of dual neutrino properties defines the symmetric two-mixing-angle form of the widely discussed four-neutrino (2 +2)-mixing scheme, as a result of the lepton charge conservation selection rule and a minimum of two Dirac neutrino fields. With neutrino duality, the two-doublet structure of the Majorana neutrino mass spectrum is a vestige of the two-Dirac-neutrino origin. The fine neutrino mass doublet structure is natural because it is produced by a lepton charge symmetry violating perturbation on a zero-approximation system of two twofold mass-degenerate Dirac neutrino–antineutrino pairs. A set of inferences related to the neutrino oscillation phenomenology in vacuum is considered.