The matter fluctuation effect to T violation at a neutrino factory

We derived an analytic formula for T violation by using the perturbation theory for small quantities, $\Delta m_{21}^2L/2E$ and $\delta a(x)L/2E$, where $\delta a(x)$ represents symmetric and asymmetric matter fluctuations, i.e., deviations from the average density. We analyzed the effect of matter fluctuations to T violation, by assuming PREM profile of earth matter density. We found that matter fluctuations do not give any viable contribution for $L<$6000km, while the fluctuation effect becomes large due to resonances for $L>$7000km. For 7000km$<L<$8000km, matter fluctuations contribute destructively to the average density term and the net result is small, while for $L>$8000km, the contribution from matter fluctuations becomes large but contributes constructively.Comment: 27 pages, 10 figure

An R-parity conserving radiative neutrino mass model without right-handed neutrinos

The model proposed by A. Zee (1986) and K.S. Babu (1988) is a simple radiative seesaw model, in which tiny neutrino masses are generated at the two-loop level. We investigate a supersymmetric extension of the Zee-Babu model under R-parity conservation. The lightest superpartner particle can then be a dark matter candidate. We find that the neutrino data can be reproduced with satisfying current data from lepton flavour violation even in the scenario where not all the superpartner particles are heavy. Phenomenology at the Large Hadron Collider is also discussed.Comment: 19 pages, 5 figure