429 research outputs found

    CP and T violation in long baseline experiments with low energy neutrino

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    Stimulated by the idea of PRISM, a very high intensity muon ring with rather low energy, we consider possibilities of observing CP-violation effects in neutrino oscillation experiments. Destructive sum of matter effect and CP-violation effect can be avoided with use of initial νe\nu_{\rm e} beam. We finally show that the experiment with (a few) ×\times 100 MeV of neutrino energy and (a few) ×\times 100 km of baseline length, which is considered in this paper, is particularly suitable for a search of CP violation in view of 3-generation nature of CP violation.Comment: 8 pages, 1 figure. To be published in the proceedings of KEK International Workshop on High Intensity Muon Sources (HIMUS 99), Tsukuba, Japan, 1-4 Dec 199

    An SU(5) SUSY Model with R-Parity Violation and Radiatively Induced Neutrino Masses

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    The radiatively induced neutrino mass matrix is investigated on the basis of an SU(5) SUSY model. In order to evade the proton decay, an ansatz based on a discrete symmetry Z2Z_2 is assumed: although, at the unification scale, we have two types of superfields ΨL(±)=5ˉL(±)+10L(±)\Psi_{L(\pm)}=\bar{5}_{L(\pm)}+10_{L(\pm)}, which are transformed as ΨL(±)±ΨL(±)\Psi_{L(\pm)} \to \pm \Psi_{L(\pm)} under the discrete symmetry Z2_2, the particles ΨL(+)\Psi_{L(+)} are decoupled after the SU(5) symmetry is broken, so that our quarks and leptons belong to \Psi_{L(-)}. The R-parity-violating terms for our quarks and leptons \Psi_{L(-)} are basically forbidden under the symmetry Z_2. However, we assume that mixings between members of \Psi_{L(+)} and those of \Psi_{L(-)} are in part caused after SU(5) is broken. As a result, the R-parity-violating interactions are in part allowed, so that the neutrino masses are radiatively generated, while the proton decay due to the R-parity violating terms is still forbidden because the term d_R^c d_R^c u_R^c has z=-1.Comment: 6 pages, Revtex, no figur

    Dynamical Symmetry Breaking in an E_6 GUT Model

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    Dynamical symmetry breaking is studied in an E_6 GUT model of a single generation of fermions with strong 4-fermi interactions. The effective potential is analyzed analytically by the help of Michel's conjecture and the result is confirmed numerically. We find that the E_6 symmetry is spontaneously broken either to F_4 or to Sp(8) or G_2 or SU(3), depending on which of the 4-fermi coupling constants G_27 and G_351 in the 27/351 channels is stronger. The possibilities for obtaining other type of breaking patterns are also discussed.Comment: 29 pages (no figures), phyzzx and tables.tex KUNS-125