Analysis of Leptogenesis in Supersymmetric Triplet Seesaw Model

We analyze leptogenesis in a supersymmetric triplet seesaw scenario that explains the observed neutrino masses, adopting a phenomenological approach where the decay branching ratios of the triplets and the amount of CP--violation in its different decay channels are assumed as free parameters. We find that the solutions of the relevant Boltzmann equations lead to a rich phenomenology, in particular much more complex compared to the non--supersymmetric case, mainly due to the presence of an additional Higgs doublet. Several unexpected and counter--intuitive behaviors emerge from our analysis: the amount of CP violation in one of the decay channels can prove to be be irrelevant to the final lepton asymmetry, leading to successful leptogenesis even in scenarios with a vanishing CP violation in the leptonic sector; gauge annihilations can be the dominant effect in the determination of the evolution of the triplet density up to very high values of its mass, leading anyway to a sizeable final lepton asymmetry, which is also a growing function of the wash--out parameter K=Gamma_d/H, defined as usual as the ratio between the triplet decay amplitude Gamma_d and the Hubble constant H; on the other hand, cancellations in the Boltzmann equations may lead to a vanishing lepton asymmetry if in one of the decay channels both the branching ratio and the amount of CP violation are suppressed, but not vanishing. The present analysis suggests that in the supersymmetric triplet see-saw model successful leptogenesis can be attained in a wide range of scenarios, provided that an asymmetry in the decaying triplets can act as a lepton--number reservoir.Comment: 14 pages, 6 figure

Phenomenology of A Supersymmetric Model for Fermion Mass Hierarchy

Some phenomenological aspects of a supersymmetric model for fermion mass hierarchy proposed previously are discussed. It is required that the lepton universality violation is near to its current experimental bound. The lepton number violation decay modes $\tau \to 2e\mu$ and $3\mu$ maybe observable in the near future. The Majorana mass of electron-neutrino is predicted to be about 0.1 eV. The fine-tuning problem is discussed.Comment: 13 pages, latex, two figures, substantially revise

A flux calibration method for remote sensing satellites using stars

Star surveys and model analyses show that many stars have absolute stable fluxes as good as 3% in 0.3-35{\mu}m wavebands and about 1% in the visible wavebands. The relative flux calibrations between stars are better than 0.2%. Some stars have extremely stable fluxes and can be used as long term flux calibration sources. Stellar brightness is several orders of magnitude lower than most ground objects while the stars do not usually appear in remote sensing cameras, which makes the stars inappropriate for being calibration sources. The calibration method using stars discussed in this paper is through a mini-camera attached to remote sensing satellite. The mini-camera works at similar wavebands as the remote sensing cameras and it can observe the stars and the ground objects alternatively. High signal-to-noise ratio is achieved for the relatively faint stars through longer exposure time. Simultaneous precise cross-calibration is obtained as the mini-camera and remote sensing cameras look at the ground objects at the same time. The fluxes from the stars used as calibration standards are transferred to the remote sensing cameras through this procedure. Analysis shows that a 2% accurate calibration is possible.Comment: 12 page