Neutrino masses, leptogenesis and dark matter in hybrid seesaw

We suggest a hybrid seesaw model where relatively ``light''right-handed neutrinos give no contribution to the neutrino mass matrix due to a special symmetry. This allows their Yukawa couplings to the standard model particles to be relatively strong, so that the standard model Higgs boson can decay dominantly to a left and a right-handed neutrino, leaving another stable right-handed neutrino as cold dark matter. In our model neutrino masses arise via the type-II seesaw mechanism, the Higgs triplet scalars being also responsible for the generation of the matter-antimatter asymmetry via the leptogenesis mechanism.Comment: 4 page

Fluctuations and scaling of inverse participation ratios in random binary resonant composites

We study the statistics of local field distribution solved by the Green's-function formalism (GFF) [Y. Gu et al., Phys. Rev. B {\bf 59} 12847 (1999)] in the disordered binary resonant composites. For a percolating network, the inverse participation ratios (IPR) with $q=2$ are illustrated, as well as the typical local field distributions of localized and extended states. Numerical calculations indicate that for a definite fraction $p$ the distribution function of IPR $P_q$ has a scale invariant form. It is also shown the scaling behavior of the ensemble averaged $$ described by the fractal dimension $D_q$. To relate the eigenvectors correlations to resonance level statistics, the axial symmetry between $D_2$ and the spectral compressibility $\chi$ is obtained.Comment: 7 pages, 6 figures, accepted by Physical Review

Six-dimensional weak-strong simulations of head-on beam-beam compensation in RHIC

To compensate the large beam-beam tune spread and beam-beam resonance driving terms in the polarized proton operation in the Relativistic Heavy Ion Collider (RHIC), we will introduce a low-energy DC electron beam into each ring to collide head-on with the opposing proton beam. The device to provide the electron beam is called an electron lens. In this article, using a 6-D weak-strong-beam-beam interaction simulation model, we investigate the effects of head-on beam-beam compensation with electron lenses on the proton beam dynamics in the RHIC 250 GeV polarized proton operation. This article is abridged from the published article [1].Comment: 5 pages, contribution to the ICFA Mini-Workshop on Beam-Beam Effects in Hadron Colliders, CERN, Geneva, Switzerland, 18-22 Mar 201

產甲烷條件下吲哚類有機物的降解途徑

Degradation of indole by an indole degrading methanogenic consortium enriched from sewage sludge proceeded through a two step hydroxylation pathway yielding oxindole and isatin. The ability of this consortium to hydroxylate and subsequently degrade substituted indoles was investigated. Of the substituted indoles tested, the consortium was able to transform or degrade 3 methylindole and 3 indolyl acetate. Oxindole, 3 methyloxindole, and indoxyl were identified as degradation metabolites of indole, 3 methylindole, and 3 indolyl acetate, respectively. Isatin (indole 2, 3 dione) was produced as an intermediate when the consortium was amended with oxindole, which provided the evidence that degradation of indole proceeded through successive hydroxylation of the 2 and 3 positions prior to ring cleavage between the C 2 and C 3 atoms on the pyrrole ring of indole. The presence of a methyl group ( CH 3 ) at either the 1 or 2 position of indole inhibited the initial hydroxylation reaction. The substituted indole, 3 methylindole, was hydroxylated at the 2 position but not at the 3 position and could not be further metabolized through the oxindole isatin pathway. Indoxyl (indole 3 one), the deacetylated product of 3 indolyl acetate, was not hydroxylated at the 2 position and thus was not further metabolized by the consortium. When an H atom or electron donating group (i.e., CH 3 ) was present at the 3 position, hydroxylation proceeded at the 2 position, but the presence of electron withdrawing substituent groups (i.e., OH or COOH) at the 3 position inhibited hydroxylation

Glassy Dynamics in a Frustrated Spin System: Role of Defects

In an effort to understand the glass transition, the kinetics of a spin model with frustration but no quenched randomness has been analyzed. The phenomenology of the spin model is remarkably similiar to that of structural glasses. Analysis of the model suggests that defects play a major role in dictating the dynamics as the glass transition is approached.Comment: 9 pages, 5 figures, accepted in J. Phys.: Condensed Matter, proceedings of the Trieste workshop on "Unifying Concepts in Glass Physics