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

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 $\nu_{\rm e}$ 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

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 $Z_2$ is assumed: although, at the unification scale, we have two types of superfields $\Psi_{L(\pm)}=\bar{5}_{L(\pm)}+10_{L(\pm)}$, which are transformed as $\Psi_{L(\pm)} \to \pm \Psi_{L(\pm)}$ under the discrete symmetry Z$_2$, the particles $\Psi_{L(+)}$ 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

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