不可忽略的弱电企鹅效应

从低能有效哈密顿及BSW方案出发,研究了企鹅图诱导的B介子两体非轻弱衰变过程中弱电企鹅图效应.通过计算发现,凡是涉及到外企鹅图的过程,弱电企鹅效应不可忽略,甚至占主导及统治地位.     

Some Possible Asymmetry Effects of Nuclear Matter in Relativistic Heavy Ion Collisions

The asymmetry dependence of nuclear incompraeaibility and that of nuclear critical temperature are calculated baaed on a Thomas-Fermi model with Seyler-Blanchard interaction. It is found that the asymmetry effects are big enough to allow for checking the existence of these effects in relativistic heavy-ion collision experiments.     

Penguin decays of B meson

The theory of loop induced rare B decays is reviewed. Both electromagnetic penguin processes and gluon mediated penguin processes are discussed. After consideringb→sy andb→se ⁺ e ^? decays, purely hadronic modes likeB→K? are estimated. Constraints on the Higgs sector of SUSY theory fromb→sy is discussed. CP violation in charged B Decays is reviewed.     

Effects of Bond Alternation on the Ground-State Phase Diagram of One-Dimensional XXZ Model

The ground-state properties and quantum phase transitions (QPTs) of the one-dimensional bond-alternative XXZ model are investigated by the infinite time-evolving block decimation (iTEBD) method. The bond-alternative effects on its ground-state phase diagram are discussed in detail. Once the bond alternation is taken into account, the antiferromagnetic phase (Δ > 1) will be destroyed at a given critical point and change into a disordered phase without nonlocal string order. The QPT is shown to be second-order, and the whole phase diagram is provided. For the ferromagnetic phase region (Δ < -1), the critical point r^c always equals 1 (independent of Δ), and the QPT for this case is shown to be first-order. The dimerized Heisenberg model is also discussed, and two disordered phases can be distinguished by with or without nonlocal string orders. Both the bipartite entanglement and the fidelity per site, as two kinds of model-independent measures, are capable of describing all the QPTs in such a quantum model.     

Effects of Bond Alternation on the Ground-State Phase Diagram of One-Dimensional XXZ Model

The ground-state properties and quantum phase transitions (QPTs) of the one-dimensional bond-alternative XXZ model are investigated by the infinite time-evolving block decimation (iTEBD) method.The bond-alternative effects on its ground-state phase diagram are discussed in detail.Once the bond alternation is taken into account,the antiferromagnetic phase (Δ 1) will be destroyed at a given critical point and change into a disordered phase without nonlocal string order.The QPT is shown to be second-order,and the whole phase diagram is provided.For the ferromagnetic phase region (Δ-1),the critical point r c always equals 1 (independent of Δ),and the QPT for this case is shown to be first-order.The dimerized Heisenberg model is also discussed,and two disordered phases can be distinguished by with or without nonlocal string orders.Both the bipartite entanglement and the fidelity per site,as two kinds of model-independent measures,are capable of describing all the QPTs in such a quantum model.     

The Characterization of Absorptive Nonlinearities

The measurement of the order and magnitude of absorptive nonlinearities is essential to the development and improvement of a wide range of optical materials. This review presents and contrasts some of the most commonly used methods for making such measurements. As background, we introduce the history of, and the essential physics behind, multiphoton absorption (MPA) and phenomena that can interfere with its measurement. We review methods for the direct and indirect measurement of MPA. The direct methods covered include nonlinear transmission, absorption modulation, Z‐scan, and spectrally‐resolved, two‐beam coupling. The indirect methods reviewed, all of which rely on the measurement of multiphoton action cross sections, include nonlinear fluorescence excitation, thermal lensing, MPA‐induced photocurrent, and various techniques for determining the order of effective nonlinear absorption in multiphoton absorption polymerization.     

Absorptive effects in the diffractive dissociation of nucleons

Absorptive effects are found to be important in diffraction dissociation. For pp→(nπ⁺)p and np→(pπ^?)p, at small excitation mass, a significant dip structure is created in the production momentum transfer distribution $\text{d}\text{σ}\text{d}\text{t}\text{d}\text{M}\text{near}\text{t = ?0.3 (}\text{GeV}\text{c}\text{)}{}^2$, in agreement with data from Fermilab and the CERN-ISR. The mass-slope correlation, seen in the data, is also reproduced. Most other distributions are affected much less by absorption.     

Finite-Size Effects on the Phase Diagram and Evolution of Strangelets in Ultrarelativistic Heavy-Ion Collisions

In the framework of multiple reflection expansion, finite-size effects are incorporated into the study of the phase diagram and evolution of a strangelet in equilibrium with a finite hadronic phase. It is found that in a significant way finite-size effects can modify the phase diagram and reduce the survival probabilities of cold strangelets in ultrarelativistic heavy-ion collisions. The inclusion of finite-size effects can also allow a quantitative analysis of the properties of a cold strangelet resulting from a smooth hydrodynamic evolution with equilibrium hadronization and isentropic expansion.     

Absorptive corrections in the photoproduction of charged π-mesons

A Regge-pole model with π-, ?-,A ₂- andR-meson exchange and absorptive corrections are used to reproduce the π^± photoproduction data in the larges, small ¦t¦ region. The starting point for the calculation of the absorptive corrections is the Regge-pole model for invariant functions.     

Effects of Density-Dependent Quark Mass on Phase Diagram of Color-Flavor-Locked Quark Matter

Considering the density dependence of quark mass, we investigate the phase transition between the (unpaired) strange quark matter and the color-flavor-locked matter, which are supposed to be two candidates for the ground state of strongly interacting matter. We find that if the current mass of strange quark ms is small, the strange quark matter remains stable unless the baryon density is very high. If ms is large, the phase transition from the strange quark matter to the color-flavor-locked matter in particular to its gapless phase is found to be different from the results predicted by previous works. A complicated phase diagram of three-flavor quark matter is presented, in which the color-flavor-locked phase region is suppressed for moderate densities.     

第三代和第四代ECR离子源:未来展望

Since the end of’70s the Electron Cyclotron Resonance ion sources(ECRIS)allowed to increase both the energy and intensity of the beams available from different types of accelerators;perspectives for the future are still optimistic.It is commonly agreed that only some ECRIS parameters have been fully exploited, whether some others are still not efficiently used,or not understood.The developments in the last 20 years have followed the so called Standard Model and the availability of higher frequency generators and higher field magnets have permitted relevant increase;the use of Nb_3Sn may extend the range.The availability of new schemes of microwave coupling to plasma is promising,and the focusing of the electromagnetic wave towards the chamber axis may improve the density of warm electron population.The paper will also describe some critical point of the 3~(rd) generation ECRIS(including technological troubles and limits)and the scenario for future 4~(th) generation ECRIS,operating at f=56—75GHz,to be built in 2010s.     

Penguin effects induced by the two-Higgs-doublet model and charmlessB-meson decays

Nonstandard physical effects through the penguin diagram induced by the charged Higgs scalar contribution in the two-Higgs-doublet model are analysed. Since non-leptonicB-decay processes to final states consisting ofs+s+ \(\bar s\) are induced only through the penguin diagram they are important tests of such contributions. We compare these decays including the non-standard two-Higgs-doublet contribution with the standard model results, which arise from the magnetic gluon transistion term. The charged Higgs contribution can give a sizable enhancement to the branching fractions ofB-meson charmless decay.     

Possible Tests of Curvature Effects in Weak Gravitational Fields

The possibility of performing in proximity of the Earth experiments to test the predictions of general relativity for the trajectories of particles and photons in weak gravitational fields is studied. Three experiments are analyzed, all based on optical detection methods. The first experiment would allow to detect the tidal acceleration using a freely-falling Michelson interferometer. In a second experiment, based on laser-ranging methods, the relativistic correction to the classical gravity acceleration could be detected. Finally, the possibility of detecting light deflection induced by space curvature in an optical cavity with high-reflectivity mirrors is discussed.     

Some Possible Roles for Topos Theory in Quantum Theory and Quantum Gravity

We discuss some ways in which topos theory (a branch of category theory) can be applied to interpretative problems in quantum theory and quantum gravity. In Sec.1, we introduce these problems. In Sec.2, we introduce topos theory, especially the idea of a topos of presheaves. In Sec.3, we discuss several possible applications of topos theory to the problems in Sec.1. In Sec.4, we draw some conclusions.     

Causal Construction of the Massless Vertex Diagram

The massless one-loop vertex diagram is constructed by exploiting the causal structure of the diagram in configuration space, which can be translated directly into dispersive relations in momentum space.     

Absorptive corrections to multihadron production and the unit intercept of the Pomeron

We propose a simple absorptive model for multihadron production in which the zero strength limit (g → 0) of the strong interactions is a vector theory, the Pomeron intercept is predicted to be at α_p=1 for any value of g, and the leading non-Pomeron singularity is at $\text{α}{}_{\mathrm{<mtext>R</mtext>}}\text{=1?}\text{g}\text{2}$. Themodel can accommodate correlations and incorporates the unitarity (Froissart) bound. Other properties of the model are discussed.     

Absorptive parts of the hadron-nucleus amplitude and multiparticle production on nuclei

The process of the hadron-nucleus interaction is considered in the framework of Glauber theory. A two-channel model is used for inelastic shadow corrections due to low-mass diffractive jets. It is shown that inelastic hadron-nucleus cross sections are connected with the cuts of a number of hadron-nucleon blobs in the elastic scattering amplitude. The relations derived between contributions to the absorptive part of the amplitude from cuts of different kinds satisfy the Abramovsky-Gribov-Kancheli rules up to a factor which is determined by the ratio of the inelastic and total hadron-nucleon cross sections. The inclusive spectrum in the central region is proportional to $\text{A}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}$. The average charged multiplicity increases with A slower than $\text{A}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}$ due to energy conservation. The results obtained are in good agreement with experimental data on the average multiplicities and distributions of charged particles.     

Some Nonlinear Rock Behavior Effects

The nonlinear rock behavior effects observed in loading diagrams are analyzed which are usually ignored in conventional models of elastoplastic media. The initial deformation stage and unloading of rock samples are considered. The nonlinear behavior on these loading stages is interpreted from the viewpoint of partial closure of cracks initiated during deformation beyond the elastic limit or in earlier loading history. Phenomenological relations are derived to account for the discussed nonlinear effects in numerical modeling. The postcritical deformation stage corresponding to the stage of strain localization and main crack formation is studied. Corrections are made to provide a more accurate determination of model parameters.     

The Phase Diagram of the Quantum Curie-Weiss Model

This paper studies a generalization of the Curie-Weiss model (the Ising model on a complete graph) to quantum mechanics. Using a natural probabilistic representation of this model, we give a complete picture of the phase diagram of the model in the parameters of inverse temperature and transverse field strength. Further analysis computes the critical exponent for the vanishing of the order parameter in the approach to the critical curve and gives useful stability properties for a variational problem associated with the representation.