CCAST World Laboratory

Taikang, China

CCAST World Laboratory

Taikang, China
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Chang C.-H.,Chongqing University | Chang C.-H.,CCAST World Laboratory | Chang C.-H.,CAS Institute of Theoretical Physics | Wang J.-X.,CAS Institute of High Energy Physics | Wu X.-G.,Chongqing University
Computer Physics Communications | Year: 2010

An upgraded (second) version of the package GENXICC (A Generator for Hadronic Production of the Double Heavy Baryons Ξc c, Ξb c and Ξb b by C.H. Chang, J.X. Wang and X.G. Wu [its first version in: Comput. Phys. Comm. 177 (2007) 467]) is presented. Users, with this version being implemented in PYTHIA and a GNU C compiler, may simulate full events of these processes in various experimental environments conveniently. In comparison with the previous version, in order to implement it in PYTHIA properly, a subprogram for the fragmentation of the produced double heavy diquark to the relevant baryon is supplied and the interface of the generator to PYTHIA is changed accordingly. In the subprogram, with explanation, certain necessary assumptions (approximations) are made in order to conserve the momenta and the QCD 'color' flow for the fragmentation. Program summary: Program title: GENXICC2.0. Catalogue identifier: ADZJ_v2_0. Program summary URL: Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland. Licensing provisions: Standard CPC licence, No. of lines in distributed program, including test data, etc.: 102 482. No. of bytes in distributed program, including test data, etc.: 1 469 519. Distribution format: tar.gz. Programming language: Fortran 77/90. Computer: Any LINUX based on PC with FORTRAN 77 or FORTRAN 90 and GNU C compiler as well. Operating system: Linux. RAM: About 2.0 MByte. Classification: 11.2. Catalogue identifier of previous version: ADZJ_v1_0. Journal reference of previous version: Comput. Phys. Comm. 177 (2007) 467. Does the new version supersede the previous version?: No. Nature of problem: Hadronic production of double heavy baryons Ξc c, Ξb c and Ξb b. Solution method: The code is based on NRQCD framework. With proper options, it can generate weighted and un-weighted events of hadronic double heavy baryon production. When the hadronizations of the produced jets and double heavy diquark are taken into account in the production, the upgraded version with proper interface to PYTHIA can generate full events. Reasons for new version: Responding to the feedback from users, we improve the generator mainly by carefully completing the 'final non-perturbative process', i.e. the formulation of the double heavy baryon from relevant intermediate diquark. In the present version, the information for fragmentation about momentum-flow and the color-flow, that is necessary for PYTHIA to generate full events, is retained although reasonable approximations are made. In comparison with the original version, the upgraded one can implement it in PYTHIA properly to do the full event simulation of the double heavy baryon production. Summary of revisions: 1.We try to explain the treatment of the momentum distribution of the process more clearly than the original version, and show how the final baryon is generated through the typical intermediate diquark precisely.2.We present color flow of the involved processes precisely and the corresponding changes for the program are made.3.The corresponding changes of the program are explained in the paper. Restrictions: The color flow, particularly, in the piece of code programming of the fragmentation from the produced colorful double heavy diquark into a relevant double heavy baryon, is treated carefully so as to implement it in PYTHIA properly. Running time: It depends on which option is chosen to configure PYTHIA when generating full events and also on which mechanism is chosen to generate the events. Typically, for the most complicated case with gluon-gluon fusion mechanism to generate the mixed events via the intermediate diquark in (c c) [3S1]3 and (c c) [1S0]6 states, under the option, IDWTUP = 1, to generate 1000 events, takes about 20 hours on a 1.8 GHz Intel P4-processor machine, whereas under the option, IDWTUP = 3, even to generate 106 events takes about 40 minutes on the same machine. © 2010 Elsevier B.V. All rights reserved.

Zhou B.-H.,Beijing University of Technology | Huang Y.-C.,Beijing University of Technology | Huang Y.-C.,CAS Institute of Theoretical Physics | Huang Y.-C.,CCAST World Laboratory
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2011

We discover an inner structure of QED while the gauge potential is decomposed into two orthogonal components. Based on this, the Lagrangian of the electron-photon system is expanded to a new form and by the general method of field theory, the gauge invariant spin and orbital angular momentum operators of the electron and photon are naturally obtained from Noether's theorem. Our method, which can be generalized to the non-Abelian systems to investigate the inner structure of QCD, provides a new perspective to look on the nucleon spin crisis and opens a window into a strict and systematic resolution of this long-standing problem. © 2011 American Physical Society.

Zheng X.-C.,CAS Institute of Theoretical Physics | Chang C.-H.,CAS Institute of Theoretical Physics | Chang C.-H.,CCAST World Laboratory | Pan Z.,CAS Institute of Theoretical Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2016

Production of the doubly heavy-flavored hadrons (Bc meson, doubly heavy baryons Ξcc, Ξbc, Ξbb, their excited states, and antiparticles of them as well) at e+e- colliders is investigated under two different approaches: LO (leading-order QCD complete calculation) and LL (leading-logarithm fragmentation calculation). The results for the production obtained by the LO and LL approaches, including the angle distributions of the produced hadrons with unpolarized and polarized incoming beams, the behaviors on the energy fraction of the produced doubly heavy-flavored hadron, and comparisons of results between the two approaches, are presented in tables and figures. Thus, characteristics of the production and uncertainties of the approaches are shown precisely, and it is concluded that only if the colliders run at the energies around the Z pole (which may be called the Z factories) and the luminosity of the colliders is as high as possible is the study of the doubly heavy-flavored hadrons completely accessible. © 2016 American Physical Society.

Wasay Abdul M.,Beijing University of Technology | Huang Y.-C.,Beijing University of Technology | Huang Y.-C.,CCAST World Laboratory | Zeng D.-F.,Beijing University of Technology | Zeng D.-F.,CAS Institute of Theoretical Physics
Nuclear Physics B | Year: 2015

We give the quantization and spectrum of an RNS supersymmetric open 2-brane described by a Polyakov-like action, the model is world-volume supersymmetric. We present the Hamiltonian of the system in terms of raising and lowering operators. We get a supersymmetric spectrum of excited states in a discrete form after a GSO-like projection, which may be useful for further exploration related to the continuous spectrum of supermembranes. © 2015 The Authors.

Wang Z.-H.,Harbin Institute of Technology | Wang G.-L.,Harbin Institute of Technology | Chang C.-H.,CCAST World Laboratory | Chang C.-H.,CAS Institute of Theoretical Physics
Journal of Physics G: Nuclear and Particle Physics | Year: 2012

We recalculate the exclusive semileptonic and nonleptonic decays of the Bc meson to a P-wave charmonium in terms of the improved BetheSalpeter (B-S) approach, which has been developed recently. Here the widths of the exclusive semileptonic and nonleptonic decays, the form factors and the charged lepton spectra for the semileptonic decays are precisely calculated. To test the concerned approach by comparing with experimental measurements when the experimental data are available, and to have comparisons with the other approaches, the results obtained by the approach and those by some other approaches as well as the original B-S approach, which appeared in the literature, are comparatively presented and discussed. © 2012 IOP Publishing Ltd.

Huang Y.-C.,Beijing University of Technology | Huang Y.-C.,CAS Institute of Theoretical Physics | Huang Y.-C.,CCAST World Laboratory | Yi L.-X.,Beijing University of Technology
Annals of Physics | Year: 2010

In this paper, we give the overview on Faddeev-Jackiw method and its improved one, as well as the relative studies recently and realize quantization of the superconductive system by the two methods, we get the same results by the two disposal methods. Furthermore, at convenience of the familiar study in this system, we take it as the application example and compare the two methods by dealing with this system from different aspects, demonstrate the improved Faddeev-Jackiw method is effective and significative, and represent the superiorities of the improved Faddeev-Jackiw method. We show that the improved method may simplify investigations of different complicated constrained systems. © 2010 Elsevier Inc.

Xing L.Y.,Soochow University of China | Yan S.L.,Soochow University of China | Yan S.L.,CCAST World Laboratory
Journal of Magnetism and Magnetic Materials | Year: 2012

Magnetic properties of the bond and crystal field dilution spin-3/2 Blume-Capel model in an external magnetic field (h) on simple cubic lattice are studied by using the effective field theory. In the m-T plane, the degeneracy of the magnetization (m) is affected by the concentration of bond or crystal field dilution at low temperature (T). The magnetization curves can appear to fluctuate in certain regions of negative crystal field. In the m-h plane, the initial magnetization curve has an irregular behavior due to the introduction of bond dilution. The crystal field dilution has the influence on the process of magnetic domain displacement. In the χ-h plane, there exists one susceptibility (χ) shoulder and one step for different negative crystal field. The susceptibility curve takes on the feature of multi-peaks distribution under bond and crystal field dilution conditions. © 2012 Elsevier B.V.

Qian X.,Soochow University of China | Yan S.L.,Soochow University of China | Yan S.L.,CCAST World Laboratory
Solid State Communications | Year: 2011

Phase transition properties of a spin-1 BlumeEmeryGriffiths model (BEGM) with random transverse crystal field is studied by the effective field theory for a simple cubic lattice. In T-Dx space, we obtain the phase diagrams with the ratio α between the biquadratic interaction and the exchange interaction as well as a tunable parameter l of the transverse crystal field. The tricritical point (TCP) appears at α<0, which undergoes a crossover from positive to negative direction of the transverse crystal field when l<0. The TCP cannot be observed for α>0. The maximum critical temperature increases with the increase of α. The position of the peak value tends to the drift of negative or positive direction for a different magnitude or an imperfect (±) transverse crystal field distribution. In T-α space, the range of ordered phase is magnified when the ratio is changed from α<0 to α>0. The random transverse crystal field obviously affects the TCP. © 2011 Elsevier Ltd. All rights reserved.

Ma P.-C.,Huaiyin Normal University | Zhan Y.-B.,CCAST World Laboratory
Optics Communications | Year: 2010

A protocol for remotely preparing a four-particle entangled cluster-type state by a set of new four-particle orthogonal basis projective measurement. It is secure that the entangled four-particle cluster-type state can be successfully realized at Bob place. Moreover we have also investigated that quantum channel shared by Alice and Bob is composed of four non-maximally entangled states. It is shown that Bob can also reestablish the original state (to be prepared remotely) with certain probability by means of appropriate unitary transformation. © 2010 Elsevier B.V. All rights reserved.

Hu B.-L.,Huaiyin Normal University | Zhan Y.-B.,Huaiyin Normal University | Zhan Y.-B.,CCAST World Laboratory
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010

We propose a scheme of generating four-qubit hyperentangled states between a pair of remote noninteracting atomic ions with a Λ configuration that are confined in Paul traps. These hyperentangled states, different from the normal entangled states that are entangled in a single degree of freedom, are entangled in both spin and motion degrees of freedom. In our proposal, the entanglement is first generated in spin degrees of freedom using linear optics and then transferred to the motion degree of freedom using a sequence of laser pluses, including the stimulated Raman carrier transitions and sideband transitions. The proposal is completed with regenerating entanglement in spin degrees of freedom using linear optics. © 2010 The American Physical Society.

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