We study a coset-space unification model for families based on E 7 /SU(5)×U(1) 3 . We find that qualitative structure of quark and lepton mass matrices in this model describes very well the observation. We stress, in particular, that the large mixing angle, sin 2 2θ νµντ ≃ 1, required for the atmospheric neutrino oscillation reported by the SuperKamiokande collaboration, is naturally obtained, which is a consequence of unparallel family structure in the present coset-space unifi-
We discuss the measurement of new physics in long baseline neutrino oscillation experiments. Through neutrino oscillations, the probability to detect new physics effects such as flavor violation is enhanced by interference with the weak interaction. We carefully explain the situations in which interference can take place. Assuming a neutrino factory and an upgraded conventional beam, we estimate the feasibility to observe new physics numerically and point out that we can search new interactions using some channels, for example, → , in these experiments. We also discuss several models which induce effective interactions interfering with the weak interaction, and show that some new physics effects are large enough to be observed in an oscillation enhanced way.
We examine how large violation effects of CP and T are allowed in long baseline neutrino experiments. When we attribute only the atmospheric neutrino anomaly to neutrino oscillation we may have large CPviolation effects. When we attribute both the atmospheric neutrino anomaly and the solar neutrino deficit to neutrino oscillation we may have sizable T violation effects proportional to the ratio of the two mass differences; it is difficult to see CP violation since we cannot ignore the matter effect. We give a simple expression for T violation in the presence of matter. ͓S0556-2821͑97͒00903-X͔ PACS number͑s͒: 14.60.Pq, 11.30.Er † Electronic address: joe@icrhp3.icrr.u-tokyo.ac.jp 1 We assume m 1 Ͻm 2
We construct a minimal calculable model of a light dilaton based on the scenario where only top and Higgs sectors are involved in a quasiconformal dynamics. The model consistently accommodates the electroweak precision tests even when the Higgs boson is very heavy, thereby allowing one to consider the possibility that the particle at around 125 GeV, discovered at the LHC experiments, is identified as the light dilaton rather than the Higgs boson. We find that the current LHC data allow distinct parameter regions where the observed particle is either mostly the Higgs boson or the dilaton.
We show simple methods how to separate pure CP violating effect from matter effect in long baseline neutrino oscillation experiments with three generations of neutrinos. We give compact formulae for neutrino oscillation probabilities assuming one of the three neutrino masses (presumably ν τ mass) to be much larger than the other masses and the effective mass due to matter effect. Two methods are shown: One is to observe envelopes of the curves of oscillation probabilities as functions of neutrino energy; a merit of this method is that only a single detector is enough to determine the presence of CP violation. The other is to compare experiments with at least two different baseline lengths; this has a merit that it needs only narrow energy range of oscillation data.
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