Search results for "solar neutrino"
showing 10 items of 286 documents
A search for time dependent neutrino emission from microquasars with the ANTARES telescope
2014
[EN] Results are presented on a search for neutrino emission from a sample of six microquasars, based on the data collected by the ANTARES neutrino telescope between 2007 and 2010. By means of appropriate time cuts, the neutrino search has been restricted to the periods when the acceleration of relativistic jets was taking place at the microquasars under study. The time cuts have been chosen using the information from the X-ray telescopes RXTE/ASM and Swift/BAT, and, in one case, the gamma-ray telescope Fermi/LAT. No statistically significant excess has been observed, thus upper limits on the neutrino fluences have been derived and compared to the predictions by models. Constraints have bee…
Calculated solar-neutrino capture rate for a radiochemical Tl205 -based solar-neutrino detector
2020
Radiochemical experiments for low-energy solar-neutrino detection have been making headlines by exploiting the isotopes $^{37}\mathrm{Cl}$ and $^{71}\mathrm{Ga}$. Such a very low-threshold measurement of this type can also be performed using $^{205}\mathrm{Tl}$, which has been considered for decades for this purpose. A unique feature of this detector nucleus is the integration in the solar-neutrino flux over ${10}^{6}$ of years owing to its long-living daughter $^{205}\mathrm{Pb}$. In this Rapid Communication, we have calculated for the first time the cross section for the charged-current solar-neutrino scattering off $^{205}\mathrm{Tl}$. Taking into account the solar-model-predicted neutri…
Isosinglet-neutral heavy-lepton production in Z-decays and neutrino mass
1990
Abstract The possible existence of NHLs is often related to neutrino mass. As a result their production cross section may be correspondingly constrained by observational limits on neutrino masses. We analyze the discovery potential of isosinglet NHLs within various models taking also into account cosmological limits on relic neutrino abundances.
Gamow–Teller beta decays of the odd-mass neighbors of the solar-neutrino detector 127I
2002
Abstract Calculations of the energy spectra and the log ft values of Gamow–Teller beta transitions of neutron-odd and proton-odd nuclei close to the solar-neutrino detector 127I are performed using the microscopic quasiparticle–phonon model. The information obtained from the beta transition strengths is valuable in solar-neutrino detection and dark matter search both in present and future large-scale experiments. Realistic interactions within a realistic single-particle valence space were used in the calculations. The overall correspondence in terms of the excitation spectra and the log ft values between theory and experiments can be regarded as quite good when considering the completely mi…
Present Knowledge of the Lepton Mixing Matrix from Neutrino Oscillation Experiments
1986
An analysis of experimental results in the framework of simultaneous oscillations of three neutrino flavours is used, in a combined fit, to constrain the elements of the 3 × 3 unitary lepton mixing matrix and to obtain limits on the three lepton mixing angles αeμ, αe τ and αμτ.
10.2 Discrete Symmetries
2008
1. The asymmetry of the zenith angle distribution of νμ of Super-Kamiokande is the direct evidence of νμ oscillations. 2. The first oscillation minimum was observed in the L/E distribution using the high resolution L/E sample of Super-Kamiokande. It confirms that the distortion of the zenith angle distribution is really due to neutrino oscillations and excludes other hypotheses such as neutrino decay and decoherence model. 3. A search for charged current (CC) interaction of ντ shows a 2.4σ excess of signal and the observed number of events is consistent with the expectation. 4. No indication of νe oscillation is observed so far in atmospheric neutrinos.
Effects of WIMP DM transport in the Sun
2011
We study the effect of dark matter (DM) particles in the Sun, focusing in particular on the possible reduction of the solar neutrinos flux due to the energy carrie d away by DM particles from the innermost regions of the Sun, and to the consequent reduction of the temperature of the solar core. We find that in the very low-mass range between 4 and 10 Ge V, recently advocated to explain the findings of the DAMA and CoGent experiments, the e ffects on neutrino fluxes are detectable only for DM models with very small, or vanishing, self-annihilation cross section, such as the so-called asymmetric DM models, and we study the combination of DM masses and Spin Dependent cross sections which can b…
Neutrino-nuclear responses for astro-neutrinos, single beta decays and double beta decays
2019
Abstract Neutrino–nuclear responses associated with astro-neutrinos, single beta decays and double beta decays are crucial in studies of neutrino properties of interest for astro-particle physics. The present report reviews briefly recent studies of the neutrino–nuclear responses from both experimental and theoretical points of view in order to obtain a consistent understanding of the many facets of the neutrino–nuclear responses. Subjects discussed in this review include (i) experimental studies of neutrino–nuclear responses by means of single beta decays, charge-exchange nuclear reactions, muon- photon- and neutrino–nuclear reactions, and nucleon-transfer reactions, (ii) implications of a…
Low-energy (anti)neutrino physics with Borexino: Neutrinos from the primary proton-proton fusion process in the Sun
2014
The Sun is fueled by a series of nuclear reactions that produce the energy that makes it shine. The primary reaction is the fusion of two protons into a deuteron, a positron and a neutrino. These neutrinos constitute the vast majority of neutrinos reaching Earth, providing us with key information about what goes on at the core of our star. Several experiments have now confirmed the observation of neutrino oscillations by detecting neutrinos from secondary nuclear processes in the Sun; this is the first direct spectral measurement of the neutrinos from the keystone proton-proton fusion. This observation is a crucial step towards the completion of the spectroscopy of pp-chain neutrinos, as we…
Using the standard solar model to constrain solar composition and nuclear reaction S factors
2013
While standard solar model (SSM) predictions depend on approximately 20 input parameters, SSM neutrino flux predictions are strongly correlated with a single model output parameter, the core temperature T-c. Consequently, one can extract physics from solar neutrino flux measurements while minimizing the consequences of SSM uncertainties, by studying flux ratios with appropriate power-law weightings tuned to cancel this T-c dependence. We reexamine an idea for constraining the primordial C + N content of the solar core from a ratio of CN-cycle O-15 to pp-chain B-8 neutrino fluxes, showing that non-nuclear SSM uncertainties in the ratio are small and effectively governed by a single parameter…