798 research outputs found

    Solar Neutrino Oscillation Parameters after KamLAND

    Full text link
    We explore the impact of the data from the KamLAND experiment in constraining neutrino mass and mixing angles involved in solar neutrino oscillations. In particular we discuss the precision with which we can determine the the mass squared difference Δmsolar2\Delta m^2_{solar} and the mixing angle θsolar\theta_{solar} from combined solar and KamLAND data. We show that the precision with which \Delta m^_{solar} can be determined improves drastically with the KamLAND data but the sensitivity of KamLAND to the mixing angle is not as good. We study the effect of enhanced statistics in KamLAND as well as reduced systematics in improving the precision. We also show the effect of the SNO salt data in improving the precision. Finally we discuss how a dedicated reactor experiment with a baseline of 70 km can improve the θsolar\theta_{solar} sensitivity by a large amount.Comment: Talk given at 4th International Conference on Nonaccelerator New Physics (NANP 03), Dubna, Russia, 23-28 Jun 200

    What can the SNO Neutral Current Rate teach us about the Solar Neutrino Anomaly

    Get PDF
    We investigate how the anticipated neutral current rate from SNOSNO will sharpen our understanding of the solar neutrino anomaly. Quantitative analyses are performed with representative values of this rate in the expected range of - 1.2. This would provide a 510σ5 - 10 \sigma signal for νe\nu_e transition into a state containing an active neutrino component. Assuming this state to be purely active one can estimate both the 8B^8B neutrino flux and the νe\nu_e survival probability to a much higher precision than currently possible. Finally the measured value of the NCNC rate will have profound implications for the mass and mixing parameters of the solar neutrino oscillation solution.Comment: Brief discussion on the first NC result from SNO added; final version to be published in the MPL

    Lepton Masses in a Minimal Model with Triplet Higgs Bosons and S3S_3 Flavor Symmetry

    Full text link
    Viable neutrino and charged lepton masses and mixings are obtained by imposing a S3×Z4×Z3S_3 \times Z_4 \times Z_3 flavor symmetry in a model with a few additional Higgs. We use two SU(2)LSU(2)_L triplet Higgs which are arranged as a doublet of S3S_3, and standard model singlet Higgs which are also put as doublets of S3S_3. We break the S3S_3 symmetry in this minimal model by giving vacuum expectation values (VEV) to the additional Higgs fields. Dictated by the minimum condition for the scalar potential, we obtain certain VEV alignments which allow us to maintain μτ\mu-\tau symmetry in the neutrino sector, while breaking it maximally for the charged leptons. This helps us to simultaneously explain the hierarchical charged lepton masses, and the neutrino masses and mixings. In particular, we obtain maximal θ23\theta_{23} and zero θ13\theta_{13}. We allow for a mild breaking of the μτ\mu-\tau symmetry for the neutrinos and study the phenomenology. We give predictions for θ13\theta_{13} and the CP violating Jarlskog invariant JCPJ_{CP}, as a function of the μτ\mu-\tau symmetry breaking parameter. We also discuss possible collider signatures and phenomenology associated with lepton flavor violating processes.Comment: 29 pages, 5 figures. Version to be appeared in PRD. Phenomenology of Lepton flavor violation and possible collider signatures of this model have been include

    Global oscillation analysis of solar neutrino data with helioseismically constrained fluxes

    Get PDF
    A seismic model for the Sun calculated using the accurate helioseismic data predicts a lower 8B^{8}{B} neutrino flux as compared to the standard solar model (SSM). However, there persists a discrepancy between the predicted and measured neutrino fluxes and it seems necessary to invoke neutrino oscillations to explain the measurements. In this work, we have performed a global, unified oscillation analysis of the latest solar neutrino data (including the results of SNO charged current rate) using the seismic model fluxes as theoretical predictions. We determine the best-fit values of the neutrino oscillation parameters and the χmin2\chi^2_{\mathrm min} for both νeνactive\nu_e-\nu_{\mathrm active} and νeνsterile\nu_e -\nu_{\mathrm sterile} cases and present the allowed parameter regions in the Δm2tan2θ\Delta m^2 - \tan^2 \theta plane for νeνactive\nu_e-\nu_{\mathrm active} transition. The results are compared with those obtained using the latest SSM by Bahcall and his collaborators.Comment: Version to appear in Phys. Rev.

    On Probing theta_{23} in Neutrino Telescopes

    Full text link
    Among all neutrino mixing parameters, the atmospheric neutrino mixing angle theta_{23} introduces the strongest variation on the flux ratios of ultra high energy neutrinos. We investigate the potential of these flux ratio measurements at neutrino telescopes to constrain theta_{23}. We consider astrophysical neutrinos originating from pion, muon-damped and neutron sources and make a comparative study of their sensitivity reach to theta_{23}. It is found that neutron sources are most favorable for testing deviations from maximal theta_{23}. Using a chi^2 analysis, we show in particular the power of combining (i) different flux ratios from the same type of source, and also (ii) combining flux ratios from different astrophysical sources. We include in our analysis ``impure'' sources, i.e., deviations from the usually assumed initial (1 : 2 : 0), (0 : 1 : 0) or (1 : 0 : 0) flux compositions.Comment: 17 pages, 5 figures. Added discussion on experimental errors. To appear in PR