We describe the effects of neutrino propagation in the matter of the Earth relevant for experiments with atmospheric and accelerator neutrinos and aimed at the determination of the neutrino mass hierarchy and CP-violation. These include (i) the resonance enhancement of neutrino oscillations in matter with constant or nearly constant density, (ii) adiabatic conversion in matter with slowly changing density, (iii) parametric enhancement of oscillations in a multi-layer medium, (iv) oscillations in thin layers of matter. We present the results of semi-analytic descriptions of flavor transitions for the cases of small density perturbations, in the limit of large densities and for small density widths. Neutrino oscillograms of the Earth and their structure after determination of the 1-3 mixing are described. A possibility to identify the neutrino mass hierarchy with the atmospheric neutrinos and multi-megaton scale detectors having low energy thresholds is explored. The potential of future accelerator experiments to establish the hierarchy is outlined.
We point out that the Hermitian and anti-Hermitian components of the effective Hamiltonian for decaying neutrinos cannot be simultaneously diagonalized by unitary transformations for all matter densities. We develop a formalism for the two-flavor neutrino propagation through matter of uniform density, for neutrino decay to invisible states. Employing a resummation of the Zassenhaus expansion, we obtain compact analytic expressions for neutrino survival and conversion probabilities, to first and second order in the "mismatch parameter" $\barγ$.
The rapid development of neutrino astronomy, which is expressed, among other things, in the emergence of new neutrino mega-projects capable of efficient registering astrophysical neutrino fluxes requires a detailed knowledge of neutrino evolution inside neutrino sources (type II supernovae, gamma-ray bursts). This evolution can be influenced by many factors, each should be accounted for by a relevant theory. In this work, we develop the theory of neutrino propagation in moving and/or polarized matter by introducing for the first time an exact spin integral of motion. This enables us to obtain …
An accurate modeling of neutrino flux attenuation and the distribution of leptons they produce in transit through the Earth is an essential component to determine neutrino flux sensitivities of underground, sub-orbital and space-based detectors. Through neutrino oscillations over cosmic distances, astrophysical neutrino sources are expected to produce nearly equal fluxes of electron, muon and tau neutrinos. Of particular interest are tau neutrinos that interact in the Earth at modest slant depths to produce $τ$-leptons. Some $τ$-leptons emerge from the Earth and decay in the atmosphere to prod…
Canonical neutrino oscillations arise due to the propagation of three mass eigenstates from production to detection. We aspire to capture, in one simple framework, a broad range of new physics effects on neutrino propagation beyond this canonical picture - this can be done by promoting the neutrino propagators to the general Källén-Lehmann form. In this work we demonstrate how models predicting additional light propagating species of neutrino are naturally accommodated in this language and propose a simple model spectrum composed of just three `broadened' states as a flexible ansatz by which t…
We analyze the potential of accelerator-based neutrino experiments, such as the Deep Underground Neutrino Experiment, to constrain a five dimensional operator mediating a beyond standard model interaction between mass dimension one fermion fields, labeled elko, and neutrino. We identify the parameter space where elko is a viable dark matter candidate.
Majorana Neutrinos as the Dark Matters in the Cold plus Hot Dark Matter Model
在冷加热暗物质的宇宙学模型中，假设两个轻中微子是等质量的热暗物质，质量为2.4 eV，研究了具有跷跷板机制的Majorana中微子的一个简单模型.我们发现，重中微子，这是跷跷板的合作伙伴与其余的一个轻中微子，可以是冷暗物质，如果轻中微子是完全无质量。这种冷的暗物质中微子的质量可以在5.9 x 10^2 eV到2.2 x 10^7 eV的宽范围内。
Universidad de Zaragoza（萨拉戈萨大学）；Centro de Astropartículas y Física de Altas Energías (CAPA), Universidad de Zaragoza（高能天体粒子中心（CAPA），萨拉戈萨大学）；Universidad de Burgos（布尔戈斯大学）
Abstract We study the analytic expression for four flavor neutrino oscillation in the presence of matter. We calculate the time evolution operator on flavor and mass basis. We find the matter dependent mass square difference and neutrino transition probabilities for (3+1) four flavor neutrino oscillation.
In this paper, we study the phenomenology of a Dirac dark matter in the $L_μ-L_τ$ model and investigate the neutrino oscillation in the dark halo. Since dark matter couples to the muon neutrino and the tau neutrino with opposite sign couplings, it contributes effective potentials, $\pm A_χ$, to the evolution equation of the neutrino flavor transition amplitude, which can be significant for high energy neutrino oscillations in a dense dark matter environment. We discuss neutrino masses, lepton mixing angles, Dirac CP phase, and neutrino oscillation probabilities in the dark halo using full nume…
We propose a simple radiative neutrino mass scenario with a Dirac dark matter candidate, which is minimally realized by a Z3 symmetry. We introduce two Dirac neutrinos and two inert doublets. We demonstrate that the model has a large allowed region that satisfies the constraints from neutrino oscillation data, lepton flavor violations, direct/indirect detection of dark matter and dark matter relic density. We also propose an efficient parameterization of the neutrino Yukawa couplings, which reproduces a desired active neutrino mass matrix.
