2474648
Neutrino masses and lepton-flavor-violating τ decays in the supersymmetric left-right model
In the supersymmetric left-right model, the light neutrino masses are given by the Type-II seesaw mechanism. A duality property of this mechanism indicates that there exist eight possible Higgs triplet Yukawa couplings which result in the same neutrino mass matrix. In this paper, we work out the one-loop renormalization group equations for the effective neutrino mass matrix in the supersymmetric left-right model. The stability of the Type-II seesaw scenario is briefly discussed. We also study the lepton-flavor-violating processes (tau -> mu gamma and tau -> e gamma) by using the reconstructed Higgs triplet Yukawa couplings.
119282212
Pure Leptonic Gauge Symmetry, Neutrino Masses and Dark Matter
Abstract A possible extension of the Standard Model to include lepton number as local gauge symmetry is investigated. In such a model, anomalies are canceled by two extra fermions doublet. After leptonic gauge symmetry spontaneously broken, three active neutrinos may acquire non-zero Majorana masses through the modified Type-II seesaw mechanism. Constraints on the model from electro-weak precision measurements are studied. Due to the Z 2 discrete flavor symmetry, right-handed Majorana neutrinos can serve as cold dark matter candidate of the Universe. Constraint from dark matter relic abundance is calculated.
118506210
Testing the realistic seesaw model with two heavy Majorana neutrinos at the CERN Large Hadron Collider
In the conventional type-(I+II) seesaw model, the effective mass matrix of three known light neutrinos is given by M(v) = M(L) - M(D)M(R)(-1)M(D)(T) in the leading-order approximation. We propose an intriguing scenario, in which the structural cancellation condition M(D)M(R)(-1)M(D)(T) = 0 is guaranteed by the A(4) x Z(2) flavor symmetry. As a consequence, neutrino masses are mainly generated by the Higgs triplet M(v) = M(L), while the neutrino mixing matrix is non-unitary and takes on the nearly tri-bimaximal pattern. A discriminating feature of this scenario from the pure type-II seesaw model is that the lepton-number-violating signatures induced by the heavy Majorana neutrinos can be discovered at the CERN Large Hadron Collider. We calculate the total cross section of the same-sign dilepton events pp -> l(alpha)(+/-)N(i) -> l(alpha)(+/-)l(beta)(+/-)jj (for i = 1, 2 and alpha, beta = e, mu, tau), and emphasize the significant interference of the contributions from two different heavy Majorana neutrinos. The background from the standard model and the kinematic cuts used to reduce it have been considered. The possible way to distinguish between the signals from heavy Majorana neutrinos and those from doubly-charged Higgs bosons is briefly discussed. (C) 2009 Elsevier B.V. All rights reserved.
122736538
Dark matter, LFV and neutrino magnetic moment in the radiative seesaw model with fermion triplet
In this paper we work in the framework of a radiative seesaw model with triplet fermion Σ. Due to the Z2 discrete flavor symmetry, the lightest neutral component of Σ is stable and thus can be a dark matter candidate. Its mass can be solely determined by the dark matter relic abundance, which is bout 2.594 TeV. It can still constitute 30% of the dark matter when considering constraints from dark matter indirect detection experiments. The model also predict a dark matter-nucleus scattering cross-section that would be accessible with future dark matter direct detection searches. We further investigate constraints on the parameter space of the model from the lepton-flavor-violating processes and neutrino transition magnetic moments, induced by the Yukawa interaction of the Σ with the left-handed lepton doublets.
118352553
The Muon Magnetic Moment in the TeV Scale Seesaw Models
The reported discrepancy of the muon abnormal magnetic moment $a_\mu^{}$ has impacts on the low energy phenomenology. In this paper we calculate the corrections to $a_\mu$ in the standard model extended by the TeV scale seesaw models. We show that the correction induced by the type-I seesaw model is negative and of the order ${\cal O} (10^{-11})$, which can be neglected compared with $a_\mu^{\rm SM}$. The correction induced by the type-II seesaw model, which depends on the mass of the Higgs triplet $m_\Delta$ and the Yukawa coupling $Y_\Delta$, can be of the order ${\cal O}(10^{-10})$ and compensate for the discrepancy between $a_\mu^{\rm SM}$ and $a_{\mu}^{\rm exp}$. The correction induced by the type-III seesaw model is also negative and can be of the order ${\cal O}(10^{-10})$.
18902857
$\pi - \pi$ Scattering Lengths and Chiral Condensate in NJL Model
Within the general framework of SU(2) Nambu-Jona-Lasinio model beyond mean-field approximation, the S-wave $\pi - \pi$ scattering lengths $a_0^0$ and $a_0^2$ are calculated. The numerical results are in agreement with that analyzed from recent experiment $\pi N \to \pi \pi N$ data by using Chew-Low-Goebel technique, and the corresponding chiral condensate $ $ is around $-(250 {\rm MeV})^3$, which is close to the ones obtained from lattice and sum rules.
103821996
The effects of gluon shadowing and nuclear absorption on J / psi suppression in h A and A A collisions
120282413
Black-hole formation in the new inflationary universe
In the new inflationary universe the fluctuation of the Higgs scalar field in the supercooled expansion stage is the origin of the irregularities observed today. It is supposed that a sufficiently large fluctuation must have caused gravitational collapse. We present a numerical model for black-hole formation in the new inflationary universe.
18594840
Production and suppression of charmonium in nuclear collisions
The J/psi production cross section considering the contributions of both color-singlet and color-octet channels is calculated. The result is used to study the suppression of J/psi in nuclear collisions. With absorption cross sections for ( )(8) sigma(abs)(8) similar or equal to 11.5+/-1.5 mb and ( )(1) sigma(abs)(1) similar or equal to 0 mb the p-A and A-B data except for Pb-Pb can be explained. Possible explanations of additional suppression in Pb-Pb are discussed. [S0556-2813(98)00605-0].
15124316
COLOR SUPERCONDUCTIVITY AT MODERATE DENSITY
The effect of color breaking on colored quarks' chiral condensates has been investigated at zero temperature and moderate baryon density. It is found that the influence of the diquark condensate on different colored quarks is very small.