Search results for "Standard solar model"
showing 10 items of 13 documents
Does the Sun Shine byppor CNO Fusion Reactions?
2002
We show that solar neutrino experiments set an upper limit of 7.8% (7.3% including the recent KamLAND measurements) to the fraction of energy that the Sun produces via the CNO fusion cycle, which is an order of magnitude improvement upon the previous limit. New experiments are required to detect CNO neutrinos corresponding to the 1.5% of the solar luminosity that the standard solar model predicts is generated by the CNO cycle.
Viewing the Sun as an X-ray star
2003
The Sun is the late-type star we can study with the highest level of detail. In the interpretation of stellar data, therefore, it is often assumed that the physical processes of the coronae of late-type stars are similar to those of the solar corona, i.e. the "solar-stellar analogy". In order to investigate the validity of this assumption, we have started a program to study systematically the Sun as an X-ray star. Our program aims to explore how far the solar model can be applied to other stars. In this paper we review the results obtained from these studies and, in particular, we discuss the variability of a star identical to the Sun during its cycle, the contribution of different coronal …
A road map to solar neutrino fluxes, neutrino oscillation parameters, and tests for new physics
2003
We analyze all available solar and related reactor neutrino experiments, as well as simulated future 7Be, p-p, pep, and ^8B solar neutrino experiments. We treat all solar neutrino fluxes as free parameters subject to the condition that the total luminosity represented by the neutrinos equals the observed solar luminosity (the `luminosity constraint'). Existing experiments show that the p-p solar neutrino flux is 1.02 +- 0.02 (1 sigma) times the flux predicted by the BP00 standard solar model; the 7Be neutrino flux is 0.93^{+0.25}_{-0.63} the predicted flux; and the ^8B flux is 1.01 +- 0.04 the predicted flux. The neutrino oscillation parameters are: Delta m^2 = 7.3^{+0.4}_{-0.6}\times 10^{-…
Solar Neutrinos Before and After Neutrino 2004
2004
We compare, using a three neutrino analysis, the allowed neutrino oscillation parameters and solar neutrino fluxes determined by the experimental data available Before and After Neutrino 2004. New data available after Neutrino2004 include refined KamLAND and gallium measurements. We use six different approaches to analyzing the KamLAND data. We present detailed results using all the available neutrino and anti-neutrino data for Delta m^2_{12}, tan^2 theta_{12}, sin^2 theta_{13}, and sin^2 eta (sterile fraction). Using the same complete data sets, we also present Before and After determinations of all the solar neutrino fluxes, which are treated as free parameters, an upper limit to the lumi…
Robust signatures of solar neutrino oscillation solutions
2001
With the goal of identifying signatures that select specific neutrino oscillation parameters, we test the robustness of global oscillation solutions that fit all the available solar and reactor experimental data. We use three global analysis strategies previously applied by different authors and also determine the sensitivity of the oscillation solutions to the critical nuclear fusion cross section, S_{17}(0), for the production of 8B. The favored solutions are LMA, LOW, and VAC in order of g.o.f. The neutral current to charged current ratio for SNO is predicted to be 3.5 +- 0.6 (1 sigma), which is separated from the no-oscillation value of 1.0 by much more than the expected experimental er…
Mass Varying Neutrinos in the Sun
2005
In this work we study the phenomenological consequences of the dependence of mass varying neutrinos on the neutrino density in the Sun, which we precisely compute in each point along the neutrino trajectory. We find that a generic characteristic of these scenarios is that they establish a connection between the effective Delta m^2 in the Sun and the absolute neutrino mass scale. This does not lead to any new allowed region in the oscillation parameter space. On the contrary, due to this effect, the description of solar neutrino data worsens for large absolute mass. As a consequence a lower bound on the level of degeneracy can be derived from the combined analysis of the solar and KamLAND da…
Status of global fits to neutrino oscillations
2004
We review the present status of global analyses of neutrino oscillations, taking into account the most recent neutrino data including the latest KamLAND and K2K updates presented at Neutrino2004, as well as state-of-the-art solar and atmospheric neutrino flux calculations. We give the two-neutrino solar + KamLAND results, as well as two-neutrino atmospheric + K2K oscillation regions, discussing in each case the robustness of the oscillation interpretation against departures from the Standard Solar Model and the possible existence of non-standard neutrino physics. Furthermore, we give the best fit values and allowed ranges of the three-flavour oscillation parameters from the current worlds' …
Solar Neutrinos Before and After KamLAND
2002
We use the recently reported KamLAND measurements on oscillations of reactor anti-neutrinos, together with the data of previously reported solar neutrino experiments, to show that: (1) the total 8B neutrino flux emitted by the Sun is 1.00(1.0 \pm 0.06) of the standard solar model (BP00) predicted flux, (2) the KamLAND measurements reduce the area of the globally allowed oscillation regions that must be explored in model fitting by six orders of magnitude in the Delta m^2-tan^2 theta plane, (3) LMA is now the unique oscillation solution to a CL of 4.7sigma, (4) maximal mixing is disfavored at 3.1 sigma, (5) active-sterile admixtures are constrained to sin^2 eta<0.13 at 1 sigma, (6) the ob…
Global Analysis of Solar Neutrino Oscillations Including SNO CC Measurement
2001
For active and sterile neutrinos, we present the globally allowed solutions for two neutrino oscillations. We include the SNO CC measurement and all other relevant solar neutrino and reactor data. Five active neutrino oscillation solutions (LMA, LOW, SMA, VAC, and Just So2) are currently allowed at 3 sigma; three sterile neutrino solutions (Just So2, SMA, and VAC) are allowed at 3 sigma. The goodness of fit is satisfactory for all eight solutions. We also investigate the robustness of the allowed solutions by carrying out global analyses with and without: 1) imposing solar model constraints on the 8B neutrino flux, 2) including the Super-Kamiokande spectral energy distribution and day-night…
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…