Types Of Neutrinos Research Articles

Integrated study of dark matter and dark energy models

Dark matter and dark energy are used as two important concepts in cosmology to explain some of the observed phenomena in the universe. Dark matter is one of the most dominant constituents of the Universe, and it influences the structural formation of the Universe through gravity, including the formation and evolution of galaxies, clusters, and the large-scale structure of the Universe. Dark energy is believed to be one of the causes of the accelerated expansion of the Universe, and its presence explains the observed phenomenon of the accelerating rate of expansion of the Universe. Although their existence has not been directly observed, people understand through the study of the structure and evolution of the universe that they play an important role in the universe. This paper first introduces the background knowledge of dark matter and its related properties and explains the reasons why three types of models, namely WIMP, axion, and sterile neutrino, are candidates for dark matter in the light of existing observations. The paper then discusses the relevant properties of dark energy and analyses the mainstream dark energy models. For the cosmological constant mode, the fine-tuning problem and cosmic coincidence problem it faces are analysed in detail. The evolution of the dark energy equation of state from the past >-1 to the present <-1 is then explained, and this is used to introduce the scalar field model involving dynamic, the Chaplygin gas model, the holographic dark energy model, and the interacting dark energy model.

Estimates of the Charges and Size of the Three Types of Neutrinos

Estimates of the Charges and Size of the Three Types of Neutrinos

Dirac-Majorana neutrino type oscillation induced by a wave dark matter

Dirac-Majorana neutrino type oscillation induced by a wave dark matter

Coherent oscillation between phonons and magnons

Consider observing two different waves with the same frequency and wavelength. When these waves are coupled, the amplitude alternates between the two waves periodically, a phenomenon called coherent beating oscillation. Such phenomena can be seen in familiar coupled pendulums and, on a cosmic scale, neutrino oscillations: the oscillation between different types of neutrinos. In solids, on the other hand, there are various wave excitations responsible for their thermal and electromagnetic properties. Here we report the observation of coherent beating between different excitation species in a solid: phonons and magnons. By using time-resolved magneto-optical microscopy, magnons generated in Lu2Bi1Fe3.4Ga1.6O12 gradually disappear by transforming to phonons, and after a while, they return to magnons. The period of the oscillation as a function of the field is consistent with the prediction of the magnon-phonon beating. The experimental results pave a way to coherent control of magnon-phonon systems in solids.

Detection techniques and investigation of different neutrino experiments

Neutrino physics is an experimentally driven field. So, we investigate the different detection techniques available in the literature and study the various neutrino oscillation experiments in a chronological manner. Our primary focus is on the construction and detection mechanisms of each experiment. Today, we know a lot about this mysterious ghostly particle by performing different experiments at different times with different neutrino sources, viz. solar, atmospheric, reactor, accelerators and high-energy astrophysical; and they have contributed in the determination of neutrino parameters. Yet the problems are far from over. We need to determine more precise values of the already known parameters and unravel the completely unknown parameters. Some of the unknowns are absolute masses of neutrino, types of neutrino, mass hierarchy, octant degeneracy and existence of leptonic CP phase(s). We analyze the neutrino experiments into the past, present and the future (or proposed). We include SNO, Kamiokande, K2K, MINOS, MINOS+, Chooz, NEMO and ICARUS in the past; while Borexino, Double Chooz, Super-K, T2K, IceCube, KamLAND, NO[Formula: see text]A, RENO and Daya Bay in the present; and SNO+, Hyper-K, T2HK, JUNO, RENO-50, INO, DUNE, SuperNEMO, KM3NeT, P2O, LBNO and PINGU in the proposed experiments. We also discuss the necessities of upgrading the present ones to those of the proposed ones thereby summarizing the potentials of the future experiments. We conclude this paper with the current status of the neutrinos.

Search for Astrophysical Neutrino Transients with IceCube DeepCore

DeepCore, as a densely instrumented sub-detector of IceCube, extends IceCube's energy reach down to about 10 GeV, enabling the search for astrophysical transient sources, e.g., choked gamma-ray bursts. While many other past and on-going studies focus on triggered time-dependent analyses, we aim to utilize a newly developed event selection and dataset for an untriggered all-sky time-dependent search for transients. In this work, all-flavor neutrinos are used, where neutrino types are determined based on the topology of the events. We extend the previous DeepCore transient half-sky search to an all-sky search and focus only on short timescale sources (with a duration of $10^2 \sim 10^5$ seconds). All-sky sensitivities to transients in an energy range from 10 GeV to 300 GeV will be presented in this poster. We show that DeepCore can be reliably used for all-sky searches for short-lived astrophysical sources.

Neutrino Temporal Oscillation

We conjecture the existence of massless neutrinos that are in the line of Standard Model (unable to account for the neutrino mass) but have characteristics that are not accounted for the Standard Model: they use a shorter radial path than the photon and possess bosonic flavors, considered like bosons instead of fermions. We call this theory “neutrino temporal oscillation”. Faced with some experimental comparisons solar neutrinos, neutrinos from SN 1987A, cosmological neutrinos, the theory gives better results, explanations and sense than the complicated theory of neutrino oscillations (transformism). The deficit of detection of solar neutrinos would have been blindly attributed to the “neutrino oscillation” by physicists who quickly concluded that the neutrino and the photon follow the same transverse path. The “OPERA” experiment which measured the speed of neutrinos in 2011 resulted, after a “superluminal” saga, in neutrino speeds consistent with the speed of light, in data that the three existing types of neutrinos cannot explain, with the final outcome of a fourth “sterile” neutrino with non-standard interaction. OPERA findings aren’t just in conflict with existing theory, but other measurements as well. For example, a study from the Kamiokande II experiment in Japan of the supernova SN1987A found that light and neutrinos that departed this exploded star arrived at Earth within hours of each other. Even though measurements of the neutrinos emitted by this supernova strongly suggest that their speeds differ from light by less than one part in a billion, the fact remains that two types of data were collected, and that only one was retained to be consistent with the existing theory. Thus, the OPERA observation is in conflicts with the result of SN1987A, which itself is highly doubtful. And what about the neutrinos and antineutrinos born during the big bang, except that they were never detected and there is nothing to indicate that their speed could be other than that of light. Neutrino physics seems sick, belief is transformed into evidence. The theory of “Neutrino temporal oscillation” shows hint that massless neutrinos can take a shortcut through the three spatial dimensions of the space-time that we know. It represents within the Standard Model an open window on a “new physics” that has a connection with physical reality.

LVD status report: neutrino physics.

The iron-scintillation detector LVD is designed to detect various types of neutrinos from collapsing stars in our Galaxy and in Magellanic Clouds. The report will present the results for 28 years of the experiment’s existence. New limit has been set on the frequency of supernova detection in our Galaxy. The results of the correlation analysis between detectors LVD and BUST are presented. The results obtained during event registration from the CERN neutrino beam are discussed.

Neutrino Transport with Monte Carlo Method. I. Toward Fully Consistent Implementation of Nucleon Recoils in Core-collapse Supernova Simulations

Abstract The small energy exchange via nucleon recoils in neutrino–nucleon scattering is now supposed to be one of the important factors for successful explosions of core-collapse supernovae (CCSNe), as they can change neutrino spectra through accumulation of a large number of scatterings. In deterministic methods employed for neutrino transport in CCSN simulations, we normally cannot afford to deploy a large enough number of energy bins needed to resolve this small energy exchange, and subgrid techniques are employed one way or another. In this paper, we study quantitatively with the Monte Carlo (MC) method how well such a treatment performs. We first investigate the effects of nucleon recoils on the neutrino spectra and confirm that the average energy is reduced by ∼15% for heavy-lepton neutrinos and much smaller amounts for other types of neutrinos in a typical postbounce situation. It is also observed that the nucleon scattering dominates the electron scattering in the thermalization of neutrino spectra in all flavors. We then study possible artifacts that the coarse energy grid may produce in the deterministic methods. In order to mimic the latter calculation, we redistribute MC particles in each energy bin after a certain interval in a couple of ways and study how the results are affected, depending on the energy resolution. We also discuss the possible implications of our results for the deterministic methods.

Consequent Quantum Mechanics by Applying 8-Dimensional Spinors in the Dirac Equation


 Aims: A consequent quantum mechanics was developed by rendering operators also for the charge and rest mass. In this formalism the Dirac equation was extended by applying 8-dimensional spinors for the decomposition of square root in the covariant equation of special relativity.
 Results: The charge and mass operators defined by 8–dimensional spinors commute with the Hamiltonian of electron and positron in electromagnetic field, but they do not commute for neutrino and quarks.
 Conclusions: For neutrino the expectation values of the rest mass and charge are zero allowing these particles moving with the speed of light. The momentum of neutrino commutes with the Hamiltonian thus it has a well-defined value for the three types of neutrinos explaining why the neutrinos can oscillate. For quarks neither the rest mass nor the charge operators commute with the Hamiltonian, thus the fractional charge and renormalized mass can be considered as expectation values in the hadron states. Since any charge measurements should give eigenvalues of its operator, no fractional charge can be detected excluding possibility of observing free quarks.

A Phenomenological Model of Effectively Oscillating Massless Neutrinos and Its Implications

We discuss an alternative picture of neutrino oscillation. In this phenomenological model, the flavor-changing phenomena of massless neutrinos arise from scattering processes between neutrinos and four types of undetected spin-0 massive particles pervading throughout the Universe, instead of neutrinos’ own nature. These scattering processes are kinematically similar to Compton scattering. One type of left-handed massless sterile neutrino is needed in order to reproduce the neutrino oscillation modes predicted in the theory of neutrino mixing. Implications of our model include the existence of sterile neu- trinos, the nonconservation of active neutrinos, the possible mismatch among three neutrino mass squared differences ∆m2ij interpreted in the theory of neutrino mixing, the spacetime dependence of neutrino oscillation, and the impossibility of neutrinoless double beta decay. Several important open problems in neutrino physics become trivial or less severe in our model, such as the smallness of neutrino masses, neutrino mass hierarchy, the mechanism responsible for neutrino masses, and the Dirac/Majorana nature of neutrinos.

Quasi-Dirac neutrino oscillations at DUNE and JUNO

Quasi-Dirac neutrinos are obtained when the Lagrangian density of a neutrino mass model contains both Dirac and Majorana mass terms, and the Majorana terms are sufficiently small. This type of neutrinos introduces new mixing angles and mass splittings into the Hamiltonian, which will modify the standard neutrino oscillation probabilities. In this paper, we focus on the case where the new mass splittings are too small to be measured, but new angles and phases are present. We perform a sensitivity study for this scenario for the upcoming experiments DUNE and JUNO, finding that they will improve current bounds on the relevant parameters. Finally, we also explore the discovery potential of both experiments, assuming that neutrinos are indeed quasi-Dirac particles.

Unitarity of neutrino mixing matrix

Neutrinos are neutral leptons and there exist three types of neutrinos (electron neutrinos νe, muon neutrinos νµ and tau neutrinos ντ). These classifications are referred to as neutrinos’s “flavors”. Oscillations between the different flavors are known as neutrino oscillations, which occurs when neutrinos have mass and non-zero mixing. Neutrino mixing is governed by the PMNS mixing matrix. The PMNS mixing matrix is constructed as the product of three independent rotations. With that, we can describe the numerical parameters of the matrix in a graphical form called the unitary triangle, giving rise to CP violation. We can calculate the four parameters of the mixing matrix to draw the unitary triangle. The area of the triangle is a measure of the amount of CP violation.

Scenario for the Origin of Matter (According to the Theory of Relation)

Where did matter in the universe come from? Where does the mass of matter come from? Particle physicists have used the knowledge acquired in matter and space to imagine a standard scenario to provide satisfactory answers to these major questions. The dominant thought to explain the absence of antimatter in nature is that we had an initially symmetrical universe made of matter and antimatter and that a dissymmetry would have sufficed for more matter having constituted our world than antimatter. This dissymmetry would arise from an anomaly in the number of neutrinos resulting from nuclear reactions which suggest the existence of a new type of titanic neutrino who would exceed the possibilities of the standard model and would justify the absence of antimatter in the macrocosm. We believe that another scenario could better explain why we observe only matter. It involves the validation of the negative energy solution of the Dirac equation, itself derived from the Einstein energy equation. The theory of Relation describes a negative energy ocean with the creation of real particle/antiparticle pairs. The origin of the masses of the particles would come from this ocean. A physical mechanism would allow their separation in the opposite direction and, therefore, the matter would be enriched at the expense of the ocean. The matter would be favored without resorting to negation or annihilation of negative energy, without the need for a CP (the behavioral difference between particle and antiparticle) violation that would be responsible for matter/antimatter asymmetry in the universe. And without the savior contribution of an undetectable obese neutrino: his search appears to us more a desperate act towards an “ultra-massive catastrophe” than a real effort to try to discover what really happened.

Instabilities of Collective Neutrino Oscillations Induced by Non-standard Neutrino Interactions

We study the effect of non-standard neutrino interactions (NSIs) on the growth of instabilities in neutrino energy spectra of a core-collapse supernova for different neutrino intensities and/or types of NSIs, notably including the exotic neutrino magnetic moment. Although it is usually attested that instabilities virtually smear out all potentially observable signatures, we show that, instead, there are regimes in which they act as a magnifying glass, bringing tiny effects to the eye of the observer.

Significant Excess of Electronlike Events in the MiniBooNE Short-Baseline Neutrino Experiment.

The MiniBooNE experiment at Fermilab reports results from an analysis of ν_{e} appearance data from 12.84×10^{20} protons on target in neutrino mode, an increase of approximately a factor of 2 over previously reported results. A ν_{e} charged-current quasielastic event excess of 381.2±85.2 events (4.5σ) is observed in the energy range 200<E_{ν}^{QE}<1250 MeV. Combining these data with the ν[over ¯]_{e} appearance data from 11.27×10^{20} protons on target in antineutrino mode, a total ν_{e} plus ν[over ¯]_{e} charged-current quasielastic event excess of 460.5±99.0 events (4.7σ) is observed. If interpreted in a two-neutrino oscillation model, ν_{μ}→ν_{e}, the best oscillation fit to the excess has a probability of 21.1%, while the background-only fit has a χ^{2} probability of 6×10^{-7} relative to the best fit. The MiniBooNE data are consistent in energy and magnitude with the excess of events reported by the Liquid Scintillator Neutrino Detector (LSND), and the significance of the combined LSND and MiniBooNE excesses is 6.0σ. A two-neutrino oscillation interpretation of the data would require at least four neutrino types and indicate physics beyond the three neutrino paradigm. Although the data are fit with a two-neutrino oscillation model, other models may provide better fits to the data.

Texture zero mass matrices and nature of neutrinos

For Majorana as well as Dirac neutrinos, attempt has been made to carry out a comparative study of the predictions of Fritzsch-like texture 6, 5 and 4 zero leptonic mass matrices. In particular, considering normal hierarchy of neutrino masses, we have examined how the parameter space available to the mixing angles with respect to the lightest neutrino mass changes for the two types of neutrinos.

A global analysis searching for neutrinos associated with black hole merger gravitational wave events

Several neutrino observatories have searched for coincident neutrino signals associated with gravitational waves induced by the merging of two black holes. No statistically significant neutrino signal in excess of the background level was observed. These experiments use different neutrino detection technologies and are sensitive to various neutrino types. A combined analysis was performed on the KamLAND, Super-Kamiokande and Borexino experimental data with a frequentist statistical approach to achieve a global picture of the associated neutrino fluence. Both monochromatic and Fermi-Dirac neutrino spectra were assumed in the calculation. The final results are consistent with null neutrino signals associated with the process of a binary black hole merger. The derived 90% confidence level upper limits on the fluence and luminosity of various neutrino types are presented for neutrino energy less than 110MeV.

Matter effects in neutrino visible decay at future long-baseline experiments

Neutrino visible decay in the presence of matter is re-evaluated. We study these effects in two future long-baseline experiments where matter effects are relevant: DUNE (1300 km) and a hypothetical beam aimed towards ANDES (7650 km). We find that matter effects are negligible for the visible component of neutrino decay at DUNE, being much more relevant at ANDES. We perform a detailed simulation of DUNE, considering nu _mu disappearance and nu _e appearance channels, for both FHC and RHC modes. The sensitivity to the decay constant alpha _3 can be as low as 2times 10^{-6} eV^2 at 90% C.L., depending on the neutrino masses and type of coupling. We also show the impact of neutrino decay in the determination of theta _{23} and delta _mathrm{CP}, and find that the best-fit value of theta _{23} can move from a true value at the lower octant towards the higher octant.

Generation of a radiative neutrino mass in the linear seesaw framework, charged lepton flavor violation, and dark matter

We investigate a model with local U(1)$_{B-L}$ and discrete $Z_2$ symmetries where two types of weak isospin singlet neutrinos, vector-like charged lepton and exotic scalar fields are introduced. The linear seesaw mechanism is induced at one-loop level through Yukawa interactions associated with the standard model leptons and exotic fields. We also discuss lepton flavor violation and muon anomalous dipole magnetic moment induced by the new Yukawa interaction. In addition, our model has dark matter candidate which is the lightest $Z_2$ odd neutral particle. We calculate the relic density and constraints from direct detection.