Partonic Effects in Heavy Ion Collisions at RHIC

Effects of partonic interactions in heavy ion collisions at RHIC are studied in a multiphase transport model (AMPT) that includes both initial partonic and final hadronic interactions.It is found that a large parton scattering cross section is needed to understand the measured elliptic flow of pions and two-pion correlation function.Comment: 10 pages, 5 figures, Workshop on Quark and Hadron Dynamics, Budapest, Hungary, March 3-7, 200

Magnetic Moments of JP=3/2+J^P={3/2}^+ Pentaquarks

If the $J^P$ of $\Theta_5^+$ and $\Xi_5^{--}$ pentaquarks is really found to be ${1\over 2}^+$ by future experiments, they will be accompanied by $J^P={3\over 2}^+$ partners in some models. It is reasonable to expect that these $J^P={3\over 2}^+$ states will also be discovered in the near future with the current intensive experimental and theoretical efforts. We estimate $J^P={3/2}^+$ pentaquark magnetic moments using different models.Comment: 13 page

Short-time critical dynamics at perfect and non-perfect surface

We report Monte Carlo simulations of critical dynamics far from equilibrium on a perfect and non-perfect surface in the 3d Ising model. For an ordered initial state, the dynamic relaxation of the surface magnetization, the line magnetization of the defect line, and the corresponding susceptibilities and appropriate cumulant is carefully examined at the ordinary, special and surface phase transitions. The universal dynamic scaling behavior including a dynamic crossover scaling form is identified. The exponent $\beta_1$ of the surface magnetization and $\beta_2$ of the line magnetization are extracted. The impact of the defect line on the surface universality classes is investigated.Comment: 11figure

Pentaquark Magnetic Moments In Different Models

We calculate the magnetic moments of the pentaquark states from different models and compare our results with predictions of other groups.Comment: 17 pages, no figur

Multipole Gravitational Lensing and High-order Perturbations on the Quadrupole Lens

An arbitrary surface mass density of gravitational lens can be decomposed into multipole components. We simulate the ray-tracing for the multipolar mass distribution of generalized SIS (Singular Isothermal Sphere) model, based on the deflection angles which are analytically calculated. The magnification patterns in the source plane are then derived from inverse shooting technique. As have been found, the caustics of odd mode lenses are composed of two overlapping layers for some lens models. When a point source traverses such kind of overlapping caustics, the image numbers change by \pm 4, rather than \pm 2. There are two kinds of images for the caustics. One is the critical curve and the other is the transition locus. It is found that the image number of the fold is exactly the average value of image numbers on two sides of the fold, while the image number of the cusp is equal to the smaller one. We also focus on the magnification patterns of the quadrupole (m = 2) lenses under the perturbations of m = 3, 4 and 5 mode components, and found that one, two, and three butterfly or swallowtail singularities can be produced respectively. With the increasing intensity of the high-order perturbations, the singularities grow up to bring sixfold image regions. If these perturbations are large enough to let two or three of the butterflies or swallowtails contact, eightfold or tenfold image regions can be produced as well. The possible astronomical applications are discussed.Comment: 24 pages, 6 figure

Heavy Pentaquarks

We construct the spin-flavor wave functions of the possible heavy pentaquarks containing an anti-charm or anti-bottom quark using various clustered quark models. Then we estimate the masses and magnetic moments of the $J^P={1\over 2}^+$ or ${3\over 2}^+$ heavy pentaquarks. We emphasize the difference in the predictions of these models. Future experimental searches at BESIII, CLEOc, BELLE, and LEP may find these interesting states