We present a short review of the existing evidence in favor of neutrino mass and neutrino oscillations which come from different kinds of experiments. We focus our attention in particular on solar ...neutrinos, presenting a global updated phenomenological analysis of all the available data and we comment on different possible future scenarios.
An updated analysis of all available neutrino oscillation evidence in Solar experiments (SK day and night spectra, global rates from Homestake, SAGE and GALLEX) including the latest SNO CC and NC ...data is presented. Assuming that the shape of the SNO CC energy spectrum is undistorted and using the information provided by SNO we obtain, for the fraction of electron neutrinos remaining in the solar beam at energies \(\gsim 5\) MeV: \(\phi_{CC}/\phi_{NC}=0.34^{+0.05}_{-0.04},\) which is nominally \(\sim 30\sigma\) away from the standard value. The fraction of oscillating neutrinos which into active ones is computed to be: \( (\Phi_{NC}-\Phi_{CC})/(\Phi_{SSM}-\Phi_{CC})=0.92^{+0.39}_{-0.20} \) nearly \(5\sigma\) deviations from the pure sterile oscillation case. The data is still compatible with an important fraction of sterile component in the solar beam (up to 20% of the total). In the framework of two active neutrino oscillations we determine individual neutrino mixing parameters and their errors in the region of no spectrum distortion (\(\Delta< T_e> <1%\)), we obtain \(\Delta m^2= 4.5^{+2.7}_{-1.4}\times 10^{-5} \eV^2, \quad \tan^2\theta=0.40^{+0.10}_{-0.08}. \) This is in agreement with the best \(chi^2\) solution in the LMA region.
We analyze the expected signals of two future neutrino experiments, kamLAND and BOREXINO. We show that with just these experiments, we will hopefully be able to determine which of the existing ...solutions to the solar neutrino problem is the real solution. We also analyze existing solar neutrino data and determine the best-fit points in the oscillation-parameter space finding that with the inclusion of SNO-charged current, the global-rates analysis gives a favored LMA solution with a goodness of fit (g.o.f) of just 32.63%, whereas the g.o.f of the SMA solution is 9.83%. Nonetheless, maximal and quasi-maximal mixing is not favored. If we include the Superkamiokande spectrum in our \chi^2 analysis, we obtain a LMA solution with a g.o.f. of 84.38%.
We analyze different phenomenological aspects of D-brane constructions. First, we obtain that scenarios with the gauge group and particle content of the supersymmetric standard model lead naturally ...to intermediate values for the string scale, in order to reproduce the value of gauge couplings deduced from experiments. Second, the soft terms, which turn out to be generically non universal, and Yukawa couplings of these scenarios are studied in detail. Finally, using these soft terms and the string scale as the initial scale for their running, we compute the neutralino-nucleon cross section. In particular we find regions in the parameter space of D-brane scenarios with cross sections in the range of \(10^{-6}\)--\(10^{-5}\) pb, i.e. where current dark matter experiments are sensitive. For instance, this can be obtained for \(\tan\beta > 5\).
We analyze the anomalous magnetic moment of the muon (a_{\mu}) in supersymmetric scenarios. First we concentrate on scenarios with universal soft terms. We find that a moderate increase of a_{\mu} ...can be obtained by lowering the unification scale M_{GUT} to intermediate values 10^{10-12} GeV. However, large values of \tan \beta are still favored. Then we study the case of non-universal soft terms. For the usual value M_{GUT}~10^{16} GeV, we obtain a_{\mu} in the favored experimental range even for moderate \tan \beta regions \tan\beta ~ 5$. Finally, we give an explicit example of these scenarios. In particular, we show that in a D-brane model, where the string scale is naturally of order 10^{10-12} GeV and the soft terms are non universal, a_{\mu} is enhanced with low \tan\beta.
Data on the free ion yield produced by gamma -radiolysis of neopentane (NP), 2,2,4,4-tetramethylpentane (TMP), tetramethylsilane (TMS), tetramethylgermanium (TMG), and tetramethyltin (TMSn) are ...analyzed using Onsager theory. Four distributed functions describing the separation distance between electron-ion pairs at thermalization were considered: a delta function (DELTA), an exponential function (EXP), an exponential modified by a first power of r (R1EXP), and an exponential modified by a quadratic power of r (R2EXP). With a suitable choice of adjustable parameters, G( infinity ) and rho , where G( infinity ) is the number of electron-ion pairs initially produced per every 100 eV released in the sample and rho is the mean thermalization distance, all four distributions approximately describe the data. For NP, TMP, and TMG, the data are best described by R1EXP; for TMSn, R2EXP is best.< >
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