117640165
Different nuclear dependence of J / psi and psi-prime production in p - A and A - p collisions
While presently available p-A data observe that the nuclear dependence of $J/\psi$ and $\psi^{\prime}$ production is the same within errors, we show that different nuclear dependence of $J/\psi$ and $\psi^{\prime}$ production in the kinematic region uncovered by the present p-A data can be predicted based on two different nuclear absorption scenarios. It is found that the predicted production ratio $\sigma (\psi^{\prime})/\sigma (J/\psi)$ at positive $x_F$ in A-p collisions is mainly determined by nuclear absorption, and hence allows direct experimental test of nuclear absorption scenarios.
118203227
Meson effects on the chiral symmetry breaking and restoration
Based on the self-consistent chiral symmetric scheme of the SU(2) Nambu-Jona-Lasinio model, the meson effects have been investigated on the chiral symmetry breaking vacuum and chiral symmetry restoration by exactly calculating the next-to-leading (NLO) order Feynman diagrams in the 1/Nc expansion.
119827604
A model for the peripheral process in ultrarelativistic nucleus-nucleus collisions
A model for the peripheral process in ultrarelativistic nucleus-nucleus collisions is proposed to explain the first experimental results of interactions of oxygen nuclei in nuclear emulsions at the highest energy now available. The fraction of the interactions producing `white' stars and the mean value of NH for different incident energies and colliding nuclei are given.
123725926
Quark propagator with a quark mass term in the color-superconducting phase
117789207
Massive meson fluctuation in NJL model
Based on the self-consistent scheme beyond the mean-field approximation in the large N-c expansion, including current quark mass explicitly, a general scheme of SU(2) NJL model is developed. To ensure the quark self-energy expanded in the proper order of N-c, an approximate internal meson propagator is deduced, which is in order of O(1/N-c). In our scheme, adopting the method of external momentum expansion, all the Feynman diagrams are calculated in a unified way by only expanding the quark propagator. Our numerical results show that, different from the mean-field approximation in which the explicitly chiral symmetry breaking is invisible, the effect of finite pion mass can be seen clearly when beyond the mean-field approximation.
18431189
Nuclear Effects on Charmonium Production
$J/\psi$ and $\psi'$ production cross sections in fixed-target experiment is calculated, considering the contributions from both color-singlet and color-octet mechanisms.The results are applied to the investigations of the $J/\psi$ suppression and the $\psi'/\psi$ ratio problems in p-A collisions. The results agree with the experimental data as the $(c \bar c)-$nucleon absorption cross sections $\sigma_{abs}^8\simeq 10mb $ for $(c \bar c)_8$ and $\sigma_{abs}^1\simeq 0mb $ for $(c \bar c)_1$. The model is further used to investigate A-A collisions when comover absorption mechanism is also considered. It is found that the observed experiment data of $J/\psi$ and $\psi'/\psi$ ratio in S-U collisions and Pb-Pb collisions can not be explained consistently within this model. The possibility of QGP formation in S-U and Pb-Pb collisions is also discussed.
10758180
Neutrino mixing and leptogenesis in type-II seesaw scenarios with left-right symmetry
Abstract We propose two type-II seesaw scenarios for the neutrino mass matrix in the left–right symmetric model, in which the Higgs triplet Yukawa coupling matrix takes the appealing Friedberg–Lee texture. We show that the nearly tri-bimaximal neutrino mixing pattern, which is especially favored by current neutrino oscillation data, can be obtained from both scenarios. We also show that the cosmological baryon number asymmetry can naturally be interpreted in these two scenarios via the flavor-independent leptogenesis mechanism.
15258004
One-loop renormalization group equations of the neutrino mass matrix in the triplet seesaw model
Within the framework of the standard model plus one heavy Higgs triplet, we derive a full set of one-loop renormalization group equations of the neutrino mass matrix and Higgs couplings in both full and effective theories. The explicit RGEs of neutrino masses, flavor mixing angles and CP-violating phases are also obtained, and their nontrivial running behaviors around the Higgs triplet mass threshold are numerically illustrated.
121701424
GRAVITATIONAL EFFECTS IN BUBBLE COLLISIONS
We investigate the effects of gravitation in the collision of two bubbles in the very early universe, using the thin-wall approximation. In general, the collision of two bubbles gives rise to modulus wall and a phase wave. The space-time metric and all physical quantities possess hyperbolic O(2,1) symmetry. We derive a generalized Birkhoff's theorem to show that the space-time in different regions must therefore be flat, de Sitter, pseudo-Schwarzschild, and pseudo-Schwarzschild-de Sitter, respectively. As in the spherically symmetric O(3) case, the space-time is Petrov type $D$, and so there is no gravitational radiation. Owing to the special symmetry of the space-time, the concentration of matter does not suffice to cause any gravitational collapse to a singularity no matter how severely the two bubbles collide. The modulus walls, viewed from the real vacuum region, eventually propagate outwards with kinks due to a series of collisions, in contrast to the situation in the absence of gravity.
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.
117946473
Black-hole creation in quantum cosmology
— It is proven that the probability of a black hole created from the de Sitter space-time background, at the WKB level, is the exponential of one quarter of the sum of the black hole and cosmological horizon areas, or the total entropy of the universe. This is true not only for the spherically symmetric cases of the Schwarzschild or Reissner-Nordstrom black holes, but also for the rotating case of the Kerr black hole and the rotating charged case of the Newman black hole. The de Sitter metric is the most probable evolution at the Planckian era of the universe.