1,453 research outputs found

    CP Violation in D0D0D^0-\overline{D^0}Mixing

    Full text link
    The existence of D0D0D^0-\overline{D^0} mixing at a detectable level requires new physics, which effectively yields a Δc=2\Delta c = 2 superweak interaction. In general this interaction may involve significant CP violation. For small values of the mixing it may be much easier to detect the CP-violating part of the mixing than the CP-conserving part.Comment: 3 pages, latex, no figure

    Consequences of Approximate S3S_3 Symmetry of the Neutrino Mass Matrix

    Full text link
    Assuming that the neutrino mass matrix is dominated by a term with the permutation symmetry S3S_{\scriptscriptstyle 3} it is possible to explain neutrino data only if the masses are quasi-degenerate. A sub-dominant term with an approximate μτ\mu -\tau symmetry leads to an approximate tri-bimaximal form. Experimental consequences are discussed.Comment: 7 pages, 2 figures, 1 table, RevTe

    CP Violation

    Get PDF
    Three possibilities for the origin of CP violation are discussed: (1) the Standard Model in which all CP violation is due to one parameter in the CKM matrix, (2) the superweak model in which all CP violation is due to new physics and (3) the Standard Model plus new physics. A major goal of B physics is to distinguish these possibilities. CP violation implies time reversal violation (TRV) but direct evidence for TRV is difficult to obtain.Comment: 13 pages, to be published in Lecture Notes of TASI-2000, edited by Jonathan L. Rosner, World Scientific, 200

    Toward a Neutrino Mass Matrix

    Get PDF
    One may identify the general properties of the neutrino mass matrix by generating many random mass matrices and testing them against the results of the neutrino experiments.Comment: 3 pages, 1 figure, talk at DPF200

    Is Ue3U_{e3} really related to the solar neutrino solutions?

    Get PDF
    It has been said that the measurements of Ue3U_{e3} in the lepton flavor mixing matrix would help discriminate between the possible solar neutrino solutions under the natural conditions with the neutrino mass hierarchies of m1m2m3m_1 \ll m_2 \ll m_3 and m1m2m3m_1 \sim m_2 \gg m_3, where mim_i is the ii-th generation neutrino absolute mass. However, it is not true, and the relation between sin22θ12\sin^2 2 \theta_{12} and Ue3U_{e3} obtained by Akhmedov, Branco, and Rebelo is trivial in actual. We show in this paper that the value of Ue3U_{e3} cannot predict the solar neutrino solutions without one additional nontrivial condition.Comment: 7pages, no figur

    Relating the scalar flavour-changing neutral couplings to the CKM matrix

    Full text link
    We build a class of two-Higgs-doublet models in which the flavour-changing couplings of the neutral scalars are related in an exact way to elements of the quark mixing matrix. In this framework, we explore the different possibilities for CP violation and find some interesting scenarios, like a realization of the superweak idea without CP violation in the BB-meson system. In another scenario the neutral scalars can be relatively light, and their contributions to the B0B^0--Bˉ0\bar{B}^0 transitions can alter the standard-model predictions for CP violation in that system.Comment: 12 pages LATEX, no figure

    Exact Parametrization of Majorana Neutrino Mass Matrix with Large Mixing

    Get PDF
    Under the assumption that the neutrinos are Majorana particles we study how the lepton mass matrices can be transformed into the simple form which has the same physical quantities by removing redundant parameters. We propose the exact parametrization of the lepton mass matrices which reflects the small nu_e-nu_mu mixing and the large nu_mu-nu_tau mixing. The relations between the twelve parameters and the physical quantities are shown. Furthermore we calculate the MNS matrix by applying the assumptions used in the quark sector. Finally we also check the validity of these assumptions from the experimental values.Comment: 11 pages, LaTeX, no figure

    Neutrinoless Double Beta Decay and CP Violation

    Full text link
    We study the relation between the Majorana neutrino mass matrices and the neutrinoless double beta decay when CP is not conserved. We give an explicit form of the decay rate in terms of a rephasing invariant quantity and demonstrate that in the presence of CP violation it is impossible to have vanishing neutrinoless double beta decay in the case of two neutrino generations (or when the third generation leptons do not mix with other leptons and hence decouple).Comment: 9 pages, UTPT-93-1

    Comment on ``Neutrino masses and mixing angles in a predictive theory of fermion masses''

    Full text link
    In the extension of the Dimopoulos--Hall--Raby model of the fermion mass matrices to the neutrino sector, there is an entry in the up-quark and neutrino Dirac mass matrices which can be assumed to arise from the Yukawa coupling of a {\bf 120}, instead of a {\bf 10} or a {\bf 126}, of SO(10). Although this assumption leads to an extra undetermined complex parameter in the model, the resulting lepton mixing matrix exhibits the remarkable feature that the ντ \nu_{\tau} does not mix with the other two neutrinos. Making a reasonable assumption about the extra parameter, we are able to fit the large-mixing-angle MSW solution of the solar-neutrino problem, and we obtain mντ10 m_{\nu_{\tau}} \sim 10 eV, the right mass range to close the Universe. Other possibilities for explaining the solar-neutrino deficit are also discussed.Comment: standard LATEX, 6 pages, 2 figures available from the authors, report No. CMU-HEP93-20 and DOE-ER/40682-4

    B Physics - A Theoretical Review

    Get PDF
    This overview of what we can hope to learn from high-statistics experiments in B physics in the next few years includes: (a) a review of parameters of the Cabibbo-Kobayashi-Maskawa (CKM) Matrix; (b) direct determination of magnitudes of CKM elements; (c) forthcoming information from studies of kaons; (d) CP violation in B decays; (e) aspects of rate measurements; (f) the role of charm-anticharm annihilation; (g) remarks on tagging; and (h) effects beyond the standard model.Comment: 23 pages, latex, 4 figures, further corrections to reference
    corecore