Non-resonant nuclear reactions at stellar temperatures

Procedure for calculating rates of non-resonant nuclear reactions at stellar temperature

Effect of Coulomb collisions on time variations of the solar neutrino flux

We consider the possibility of time variations of the solar neutrino flux due to the radial motion of the Earth and neutrino interference effects. We calculate the time variations of the detected neutrino flux and the extent to which they are suppressed by Coulomb collisions of the neutrino emitting nuclei. To properly treat the collisions, it is necessary to simultaneously include in our analysis all other significant physical decoherence effects: the energy averaging and the averaging over the position of neutrino emission. A simple and clear physical picture of the time dependent solar neutrino problem is presented and qualitative coherence criteria are discussed. Exact results for the detected neutrino flux and its time variations are obtained for both the case of a solar neutrino line, and the case of the continuous neutrino spectrum with a Gaussian shape of the energy response function of the neutrino detector. We give accurate constraints on the vacuum mixing angle and the neutrino masses required for flux time variations to not be suppressed. Pac(s): 26.65.+t, 14.60.Pq, 96.60.JwComment: 43 pages, 8 figures, 4 appendices; changed title, MSW jump probability formula and figure

How many sigmas is the solar neutrino effect?

The minimal standard electroweak model can be tested by allowing all the solar neutrino fluxes, with undistorted energy spectra, to be free parameters in fitting the measured solar neutrino event rates, subject only to the condition that the total observed luminosity of the sun is produced by nuclear fusion. The rates of the five experiments prior to SNO (chlorine, Kamiokande, SAGE, GALLEX, Super-Kamiokande) cannot be fit by an arbitrary choice of undistorted neutrino fluxes at the level of 2.5 sigma (formally 99% C.L.). Considering just SNO and Super-Kamiokande, the discrepancy is at the 3.3 sigma level(10^{-3} C.L.). If all six experiments are fit simultaneously, the formal discrepancy increases to 4 sigma (7*10^{-5} C.L.). If the relative scaling in temperature of the nuclear reactions that produce 7Be and 8B neutrinos is taken into account, the formal discrepancy is at the 7.4 sigma level.Comment: 1 figure; related information at http://www.sns.ias.edu/~jn

Probability of a Solution to the Solar Neutrino Problem Within the Minimal Standard Model

Tests, independent of any solar model, can be made of whether solar neutrino experiments are consistent with the minimal Standard Model (stable, massless neutrinos). If the experimental uncertainties are correctly estimated and the sun is generating energy by light-element fusion in quasi-static equilibrium, the probability of a standard-physics solution is less than 2%. Even when the luminosity constraint is abandoned, the probability is not more than 4%. The sensitivity of the conclusions to input parameters is explored.Comment: PRL, Revtex, 1 figure, 5 page

Solar neutrino interactions: Using charged currents at SNO to tell neutral currents at Super-Kamiokande

In the presence of flavor oscillations, muon and tau neutrinos can contribute to the Super-Kamiokande (SK) solar neutrino signal through the neutral current process \nu_{\mu,\tau} e^{-}\to \nu_{\mu,\tau} e^{-}. We show how to separate the \nu_e and \nu_{\mu,\tau} event rates in SK in a model independent way, by using the rate of the charged current process \nu_e d \to p p e^{-} from the Sudbury Neutrino Observatory (SNO) experiment, with an appropriate choice of the SK and SNO energy thresholds. Under the additional hypothesis of no oscillations into sterile states, we also show how to determine the absolute ^{8}B neutrino flux from the same data set, independently of the \nu_e survival probability.Comment: 14 pages (RevTeX), incl. 3 figures (epsf), submitted to Phys. ReV.

Shape of the 8B Alpha and Neutrino Spectra

The beta-delayed alpha spectrum from the decay of 8B has been measured with a setup that minimized systematic uncertainties that affected previous measurements. Consequently the deduced neutrino spectrum presents much smaller uncertainties than the previous recommendation. The 8B neutrino spectrum is found to be harder than previously recommended with about (10-20)% more neutrinos at energies between 12-14 MeV. The efficiencies of the 37Cl, 71Ga, 40Ar, and SuperKamiokande detectors are respectively, 3.6%, 1.4%, 5.7% and 1.8% larger than previously thought.Comment: 4 pages, 5 figure

Guide star probabilities

Probabilities are calculated for acquiring suitable guide stars (GS) with the fine guidance system (FGS) of the space telescope. A number of the considerations and techniques described are also relevant for other space astronomy missions. The constraints of the FGS are reviewed. The available data on bright star densities are summarized and a previous error in the literature is corrected. Separate analytic and Monte Carlo calculations of the probabilities are described. A simulation of space telescope pointing is carried out using the Weistrop north galactic pole catalog of bright stars. Sufficient information is presented so that the probabilities of acquisition can be estimated as a function of position in the sky. The probability of acquiring suitable guide stars is greatly increased if the FGS can allow an appreciable difference between the (bright) primary GS limiting magnitude and the (fainter) secondary GS limiting magnitude

Tests of electron flavor conservation with the Sudbury Neutrino Observatory

We analyze tests of electron flavor conservation that can be performed at the Sudbury Neutrino Observatory (SNO). These tests, which utilize $^8$B solar neutrinos interacting with deuterium, measure: 1) the shape of the recoil electron spectrum in charged-current (CC) interactions (the CC spectrum shape); and 2) the ratio of the number of charged current to neutral current (NC) events (the CC/NC ratio). We determine standard model predictions for the CC spectral shape and for the CC/NC ratio, together with realistic estimates of their errors and the correlations between errors. We consider systematic uncertainties in the standard neutrino spectrum and in the charged-current and neutral current cross-sections, the SNO energy resolution and absolute energy scale, and the SNO detection efficiencies. Assuming that either matter-enhanced or vacuum neutrino oscillations solve the solar neutrino problems, we calculate the confidence levels with which electron flavor non-conservation can be detected using either the CC spectrum shape or the CC/NC ratio, or both. If the SNO detector works as expected, the neutrino oscillation solutions that best-fit the results of the four operating solar neutrino experiments can be distinguished unambiguously from the standard predictions of electron flavor conservation.Comment: 31 pages (RevTeX) + 10 figures (postscript). Requires epsfig.sty. Gzipped figures also available at ftp://ftp.sns.ias.edu/pub/lisi/snopaper . To appear in Phys. Rev.

Do Solar Neutrino Experiments Imply New Physics?

None of the 1000 solar models in a full Monte Carlo simulation is consistent with the results of the chlorine or the Kamiokande experiments. Even if the solar models are forced artifically to have a \b8 neutrino flux in agreeement with the Kamiokande experiment, none of the fudged models agrees with the chlorine observations. The GALLEX and SAGE experiments, which currently have large statistical uncertainties, differ from the predictions of the standard solar model by $2 \sigma$ and $3 \sigma$, respectively.Comment: 7 pages (figures not included), Institute for Advanced Study number AST 92/51. For a hard copy with the figures, write: [email protected]