High-energy Neutrino Flux Research Articles

Detailed neutrino spectra from cold dark-matter annihilations in the sun

Cold dark-matter particles captured by the Sun can annihilate and may produce an observable flux of high-energy neutrinos. We discuss the effects of the solar medium upon the neutrino flux. Muons, pions, and kaons lose their energy to the medium before undergoing a weak decay, so that the flux is dominated by prompt neutrinos from τ, c, b, or t decays. We calculate the differential fluxes of neutrinos from annihilations via τ τ , c c , b b , and t t final states using a successful model for final states in e + e − collisions augmented by our solar medium considerations. Fragmentation and finite-mass effects are important for b and c decays. For sufficiently energetic fermions, stopping and absorption are important. We give the results of our calculations in a form useful for estimating event rates in terrestrial experiments. Finally, we apply our results to the case of a superstring dark-matter candidate.

Effects of Resonant Matter Oscillation in Earth on Solar Neutrino Detection

Subject of the neutrino oscillation has recently gained a renewed interest by the discovery of the resonant matter oscillation!) (MSW effect). When applied to the solar neutrino problem, this mechanism gives an elegant solution to the deficie) of the high energy neutrino flux even if the mixing angle is much smaller than what is required in the case of vacuum oscillation. Subsequently effects of matter oscillation in earth 3

High-energy neutrinos from the sun and cold dark matter

We consider in detail the possibility of a flux of high-energy neutrinos from the sun due to the annihilation within of particles which make up the galactic halo. Specifically, if the halo consists of heavy neutrinos or stable supersymmetric particles with mass ≳6 GeV, halo particles will be trapped in the sun and annihilate to produce a potentially observable high-energy neutrino flux. We provide detailed estimates of this flux for a variety of candidate halo particles: photinos, higgsinos, scalar neutrinos, heavy Dirac neutrinos, and heavy Majorana neutrinos. All of these can (for appropriate ranges of parameters) produce fluxes whose absolute value is at least comparable to atmospheric background. We briefly discuss how the solar fluxes could be distinguished from the background. We also discuss the effect of trapped halo particles on the solar neutrino problem.

Solar models with energy transport by weakly interacting particles

view Abstract Citations (111) References (18) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Solar Models with Energy Transport by Weakly Interacting Particles Gilliland, R. L. ; Faulkner, J. ; Press, W. H. ; Spergel, D. N. Abstract Accretion by the sun of weakly interacting massive particles (WIMPs or cosmions) from a background population leads to efficient nonlocal energy transport in the solar core. At concentrations as low as 10 to the -11th by number, such particles, with ideal scattering cross sections, can lower the central temperature sufficiently to bring the predicted neutrino detection rate into agreement with observations. Since the perturbation is restricted to a small core, only small adjustments to the free parameters (initial hydrogen abundance and convection mixing length) are required to produce standard solar models with significantly lower (high-energy) neutrino fluxes. Publication: The Astrophysical Journal Pub Date: July 1986 DOI: 10.1086/164380 Bibcode: 1986ApJ...306..703G Keywords: Energy Transfer; Solar Neutrinos; Stellar Structure; Weak Interactions (Field Theory); Energy Distribution; Flux (Rate); Stellar Evolution; Stellar Models; Temperature Distribution; Solar Physics; ELEMENTARY PARTICLES; NEUTRINOS; SUN: INTERIOR full text sources ADS |

Can neutrinos from Cygnus X-3 be seen by proton decay detectors?

The flux of high-energy neutrinos from Cygnus X-3 is estimated directly from the observed light curve of high-energy γ-rays from this source. These neutrinos induce an underground muon flux which can be distinguished by its characteristic direction and duration from the muon background induced by atmospheric neutrinos. For zenith angles ≥ 84° the expected rate of muon events in the IMB detector due to Cygnus X-3 is between 1 and 10 events/yr, depending on the actual duration of the γ-ray pulses from this source.

High energy neutrino astrophysics

High-energy neutrino astrophysics (Ev = 30-100 GeV) is briefly discussed. Neutrino detection methods and neutrino sources are summarized, giving the dimensions of some detectors. Results of calculations of the flux of high-energy neutrinos from Cygnus X-3 are presented. 11 references.

On the origin of relativistic particles and gamma-rays in quasars

A model for a class of quasars and active galactic nuclei is proposed in which a shock around a massive black hole randomizes the infall kinetic energy of spherically accreting matter producing a nonthermal spectrum of high energy protons. It is suggested that these protons are responsible for the secondary production (via proton decay) of the radio emitting high energy electrons and also of high energy gamma-rays (via proton decay and inverse Compton interactions of the electrons). The correlation between radio and gamma-ray emission implied by the model is in good agreement with observations of 3C273. Observation of the flux of high energy neutrinos from quasars may provide a test for the model.

High-energy cosmic-ray neutrinos and tau particles

We propose a possible scheme that will accommodate the newly discovered tau particle in the generic relation between cosmic-ray particles at high energy. The scheme imposes a new lower mass limit on the tau-neutrino, 139 <\(M_{v_\tau } \) < 250 MeV. A possible contribution of the tau-neutrino to high-energy neutrino flux is discussed. We then analyse the possible astrophysical situations suitable for the production of the tau particle and its neutrino.

Production of High-Energy Deuterons in theHe3+He3Reaction and the Solar Neutrino Problem

A spectrum of deuterons consistent with the reaction $^{3}\mathrm{He}+^{3}\mathrm{He}\ensuremath{\rightarrow}^{2}\mathrm{H}+^{4}\mathrm{He}+{e}^{+}+\ensuremath{\nu}$ has been detected with a system sensitive to cross sections of 300 pb ${\mathrm{sr}}^{\ensuremath{-}1}$ Me${\mathrm{V}}^{\ensuremath{-}1}$. The measured cross section is too high for a weak-interaction process: 3.4 nb Me${\mathrm{V}}^{\ensuremath{-}1}$ ${\mathrm{sr}}^{\ensuremath{-}1}$. It might be due to an interaction of intermediate strength and it could explain the low flux of high-energy solar neutrinos.

Search for solar-neutrino related M1 transitions in 6Li using 180° electron scattering

The 6Li analog of the 11.5 MeV, 0 + state in 6Be proposed to explain the low flux of high-energy solar neutrinos has been searched for and not observed. An upper limit of 3 eV is placed on the M1 ground-state width of any such narrow 0 + state.

Foreword

The purpose of this meeting is to discuss recent experiments on very energetic neutrinos and to bring together people who are working in the subject either with the artificial sources provided by the great accelerators, or with the flux of high energy neutrinos provided by the cosmic radiation. During the past five years very important advances have been made with the recognition of two types of neutrinos, the electron neutrino and the muon neutrino, both of spin ½ , and both, so we believe, of zero rest-mass. In spite of the very weak interaction of these particles with matter, it has been found possible to demon­strate that the two types produce different effects and some of the most important results of their interactions with neutrons and protons have been clearly demon­strated. The intensities of the neutrino beams so far generated by the machines are such that the experiments are among the most exacting in physics, and the limitation on the energy of the particles has had the consequence that it has been possible to put only an upper limit of about 3 GeV on the mass of the heavy boson through which, so it is speculated, the field of the weak interactions is mediated.

IV. High energy neutrinos underground: status of the Case-Wits-Irvine experiment and future prospect

It is part of the folklore of cosmic ray physics dating back to the 1940’s that if one could only go deeply enough underground with a suitably large detector, it would be possible to detect neutrinos in the cosmic radiation. I say ‘folklore’ because no estimates of flux were available, the variation of cosmic ray intensity with depth was known to very shallow depths indeed (a few hundred metres of rock), detection techniques were relatively insensitive and nothing was known about interaction cross-sections, let alone the existence of muon neutrinos. The intervening two decades have witnessed developments and discoveries in all these directions so that it became possible to calculate the spectra of high energy (&gt; 1 GeV) neutrinos resulting from the interaction of cosmic ray primaries with the Earth’s atmosphere and to begin speculation regarding high energy extra terrestrial sources. Measure­ments at high energy machines made it possible to put a lower bound on the interaction of neutrinos in the supra machine range. The discovery of the muon neutrino revealed the existence of a product with long range, the muon, which results from the interaction of muon type neutrinos with nuclei. This feature of the neutrino interaction, the muon associated neutrino, is central to all cosmic ray detection schemes. The electron-neutrino interaction observed long ago by the Los Alamos group is relatively ineffective because of the short range of the product electron. The great strides made in the field of particle detection with the development of efficient and relatively inexpensive large area scintillation detectors showed that finite count rates, ca . 10/y, could be expected from detectors measuring ca . 10 2 m 2 in area. Finally, the measurements of the intensity of cosmic rays with depth-pursued most effectively by the groups working at the Kolar Gold Fields in India-showed that neutrino interactions could be sought in existing deep mines without too much trouble from cosmic ray muons which succeeded in penetrating from the surface of the Earth to the detector. The motivation for seeking to measure and understand the high energy neutrino flux from our atmosphere and beyond is twofold: (1) This source, though weak and not under our control, is of much higher energy than available, or is likely to become available, in the laboratory for some time to come. It is generally recognized that energy is a prime factor in probing the structure of the weak interaction. (2) A curiosity regarding the existence and nature of sources of extraterrestrial neutrinos. A more mundane but perfectly valid reason for studying atmospheric neutrinos is a desire to ‘tidy up’ the record of cosmic ray components as they are produced and interact in the Earth’s atmosphere.

Astronomical Tests of the Existence ofLi4

The possible existence of the isotope Li/sup 4/ is discussed, and its important astrophysical implications are considered. If it is concluded that Li/ sup 4/ exists, it would lead to the stellar reactions H/sup 1/(H/sup 1/, e+ )H/ sup 2/(H/sup 1/, )H/sup 3/ (H/sup 1/, barrier of the third step. As a consequence of these reactions a large flux of high energy neutrinos could be expected at the earth's surface (10/sup 11/ neutrinos/cm/sup 2/ sec). The failure to detect such a flux at Savannah River constitutes a strong case against the existence of Li/sup 4/. (W.D.M.)