58 research outputs found

    A simple scheme for masses and mixings of quarks and neutrinos

    Get PDF
    The mass matrices of charged fermions have a simple structure if expressed in powers of the small parameter sigma=(m_c/m_t)^{1/2}. It is suggested that the mass matrix of the three heavy neutrinos occuring in grand unified theories can be expressed in terms of the same parameter. The requirement that these heavy neutrinos carry different U(1) generation quantum numbers gives rise to an almost unique form for this matrix. By applying the see-saw mechanism, the mass splitting of the two lightest neutrinos comes out to be tiny, favoring the vacuum oscillation solution for solar neutrinos. The mixing matrix is of the bimaximal type but contains also CP violating phases.Comment: 9 pages, references added and minor correction

    Exclusive Hadronic B-Decays

    Get PDF
    Exclusive non-leptonic two-body decays are discussed on the basis of a generalized factorization approach which also includes non-factorizeable contributions. Numerous decay processes can be described satisfactorily. The success of the method makes possible the determination of decay constants from non-leptonic decays. In particular, we obtain f_{D_s}=(234+-25) MeV and f_{D^*_s}=(271+-33) MeV. The observed constructive and destructive interference pattern in charged B- and D-decays, respectively, can be understood in terms of the different alpha_s-values governing the interaction among the quarks. The running of alpha_s is also the cause of the observed strong increase of the amplitude of lowest isospin when going to low energy transitions.Comment: 11 pages, LaTeX, uses epsf.sty, one eps figure, plenary talk at the b20 Symposium, Chicago, July 199

    Non-Leptonic Weak Decays of B Mesons

    Get PDF
    We present a detailed study of non-leptonic two-body decays of B mesons based on a generalized factorization hypothesis. We discuss the structure of non-factorizable corrections and present arguments in favour of a simple phenomenological description of their effects. To evaluate the relevant transition form factors in the factorized decay amplitudes, we use information extracted from semileptonic decays and incorporate constraints imposed by heavy-quark symmetry. We discuss tests of the factorization hypothesis and show how unknown decay constants may be determined from non-leptonic decays. In particular, we find f_{Ds}=(234+-25) MeV and f_{Ds*}=(271+-33) MeV.Comment: two references added and one entry in Table 9 corrected; to appear in the Second Edition of "Heavy Flavours", edited by A.J. Buras and M. Lindner (World Scientific, Singapore

    The mass of the Higgs boson in the trinification subgroup of E6

    Full text link
    The extension of the standard model to SU(3)_L x SU(3)_R x SU(3)_C is considered. Spontaneous symmetry breaking requires two Higgs field multiplets with a strong hierarchical structure of vacuum expectation values. These vacuum expectation values, some of them known from experiment, are used to construct invariant potentials in form of a sum of individual potentials relevant at the weak scale. As in a previous suggestion one may normalize the most important individual potentials such that their mass eigenvalues agree with their very large vacuum expectation values. In this case (for a wide class of parameters) the scalar field corresponding to the standard model Higgs turns out to have the precise mass value m_Higgs = v/sqrt(2) = 123 GeV at the weak scale. The physical mass (pole mass) is larger and found to be 125 +/- 1.4 GeV.Comment: 5 pages, version appearing in Phys. Rev.

    Trinification phenomenology and the structure of Higgs bosons

    Get PDF
    The extension of the Standard Model to SU(3)LĂ—SU(3)RĂ—SU(3)CSU(3)_L \times SU(3)_R \times SU(3)_C (the trinification group) augmented by the SO(3)G SO(3)_G flavor group is considered. In our phenomenological treatment partly known and partly proposed vacuum expectation values of the scalar Higgs fields play a dominant role. All Higgs fields are taken to be flavor singlets, all flavon fields trinification singlets. We need two flavor (generation) matrices. One determines the mass hierarchy of all fermions, the second one is responsible for all mixings including the CP-violating phase in the CKM matrix. The mixing with higher states contained in the group representation provides for an understanding of the difference between the up quark and the down quark spectrum. There is a close connection between charged and neutral fermions. An inverted neutrino hierarchy is predicted. Examples for the tree-level potential of the Higgs fields are given. To obtain an acceptable spectrum of scalar states, the construction of the potential requires the combination of matrix fields that differ with respect to fermion couplings and flavor-changing properties. As a consequence bosons with fermiophobic components or, alternatively, flavor-changing components are predicted in this model. Nevertheless, the Higgs boson at 125 GeV is very little different from the Standard Model Higgs boson in its couplings to fermions but may have self-coupling constants larger by a factor 2.Comment: 12 pages, minor corrections, version accepted for publication in JHE
    • …
    corecore