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in creator/contributor: "Wong, C.Y."

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Origin of anomalous positron peaks in heavy-ion reactions

Unknown neutral objects, which decay into an electron and a positron with sharp energies, are found to be produced in heavy-ion reactions. The author discuss the possible origins of these objects and examine phenomenologically the consequences of a supercritical interaction between an electron and a positron due to their short-range non-central electromagnetic interactions. We study how an (e/sup +/e/sup -/) composite particle may be coupled to a strong nuclear Coulomb field.

Date: January 1, 1988

Creator: Wong, C. Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Dynamics of high-energy nucleus-nucleus collisions

The authors use a Glauber multiple-collision model to examine the dynamics of nucleus-nucleus collisions. The model introduces a stopping law, which describes how a baryon loses energy in a baryon-baryon collision, and a particle production law, which is based on the baryon energy loss. The model gives results on the longitudinal energy loss which compare well with the recent WA80 experimental data for /sup 16/O on various targets at 60 and 200 GeV per nucleon. The stopping law that is needed t… more

Date: January 1, 1988

Creator: Wong, C. Y. & Lu, Z. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Vibrational instability: a possible test of nuclear hydrodynamics

In the controlled collisions of water droplets, an instability arises which was not predicted by theory. Nevertheless, it is believed that some well-established theoretical hydrodynamical considerations promise to describe the phenomenon in a very simple and intuitive way. As a result, there arises the prospect of testing, perhaps with some rigor, the qualitative question of whether the nuclear fluid dynamics can properly be described as hydrodynamics (i.e., by means of a Navier--Stokes equatio… more

Date: January 1, 1976

Creator: Griffin, J. J. & Wong, C. Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A detailed study of nonperturbative solutions of two-body Dirac equations

In quark model calculations of the meson spectrums fully covariant two-body Dirac equations dictated by Dirac`s relativistic constraint mechanics gave a good fit to the entire meson mass spectrum for light quark mesons as well as heavy quark mesons with constituent world scalar and vector potentials depending on just one or two parameters. In this paper, we investigate the properties of these equations that made them work so well by solving them numerically for quantum electrodynamics (QED) and… more

Date: December 1, 1992

Creator: Crater, H. W.; Becker, R. L.; Wong, C. Y. & Van Alstine, P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Extended TDHF Approximation Illuminates the Approach to Thermal Equilibrium

The region of validity of the TDHF approximation is extended by including the collisions between particles. The resultant equations of motion consist of a modified TDHF equation and a master equation for the occupation numbers. Concepts such as entropy, temperature, and thermal equilibrium can be quantitatively introduced. The well-known H-theorem that entropy never decreases is proved for nuclear systems. New types of level crossing formulas are obtained to shed light on how a nonequilibrium f… more

Date: January 1, 1979

Creator: Wong, C.Y. & Tang, H.H.K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A detailed study of nonperturbative solutions of two-body Dirac equations

In quark model calculations of the meson spectrums fully covariant two-body Dirac equations dictated by Dirac's relativistic constraint mechanics gave a good fit to the entire meson mass spectrum for light quark mesons as well as heavy quark mesons with constituent world scalar and vector potentials depending on just one or two parameters. In this paper, we investigate the properties of these equations that made them work so well by solving them numerically for quantum electrodynamics (QED) and… more

Date: December 1, 1992

Creator: Crater, H. W.; Becker, R. L.; Wong, C. Y. & Van Alstine, P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Classical transcription of the TDHF approximation

The time-dependent Hartree--Fock approximation is shown to be approximately equivalent to a purely classical pseudoparticle simulation. In this simulation, a collection of pseudoparticles are introduced to discretize the phase space of spatial and momentum coordinates. The dynamics is completely determined by following the pseudoparticle trajectories which are the same as the trajectories of real particles moving in the self-consistent field. An application of these concepts to nearly-head-on h… more

Date: January 1, 1979

Creator: Wong, C.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Central collisions in intermediate energy heavy-ion reactions. [Micro- and macroscopic theory, extended time-dependent Hartree-Fock approximation]

The critical collisions in intermediate energy heavy-ion reactions are examined from both a microscopic and macroscopic viewpoint. In the microscopic description the proper tool is the extended TDHF approximation involving both the mean field and the particle collisions. To understand the underlying physics, the effect of the mean field and the effect of particle collisions are studied separately. It is found that th sudden increase in the density of the overlapping region can cause the volcano… more

Date: January 1, 1979

Creator: Wong, C.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Nuclear momentum distribution and relativistic heavy-ion reactions

In terms of a direction fragmentation process and a hard-scattering process, the proton-inclusive data for the reaction ..cap alpha.. + /sup 12/C ..-->.. p + X were successfully analyzed. The extracted semiempirical momentum distribution indicates possible evidence of nuclear correlations and final-state interactions. 4 figures.

Date: January 1, 1980

Creator: Wong, C.Y. & Blankenbecler, R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Scaling phenomenon in relativistic nucleus-nucleus collisions

New scaling variables for proton and pion production in relativistic nucleus-nucleus collisions are introduced which are the generalizations of the Feynmann scaling variable. They allow a simple description of the cross sections at forward and backward angles. 2 figures.

Date: January 1, 1980

Creator: Wong, C.Y. & Blankenbecler, R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Viscoelastic properties of the nucleus

The Maxwell solid, which has a short-time elastic behavior and a long-time viscous behavior, cannot properly describe the viscoelastic properties of the nuclear fluid in its ground state. The Voigt solid, which exhibits asymptotically an elastic behavior, is a good model for the nuclear fluid in its ground state.

Date: January 1, 1982

Creator: Wong, C.Y. & Azziz, N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Particle productions in high-energy, heavy-ion reactions

Results of Blankenbecler, et al. for hadron-nucleus collisions are generalized to heavy-ion collisions. Explicit expressions relating nucleon-nucleon to nucleus-nucleus partial cross sections are given.

Date: January 1, 1982

Creator: Wong, C.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Initial energy density of quark-gluon plasma in relativistic heavy-ion collisions

Recently, there has been considerable interest in the central rapidity region of highly relativistic heavy-ion collisions. Such an interest stems from the possibility of creating hadron matter of high energy density which may exceed the critical energy density for a phase transition between ordinary confined matter and the unconfined quark-gluon plasma. The experimental searches and identification of the quark-gluon plasma may provide a new insight into the question of quark confinement. The es… more

Date: January 1, 1984

Creator: Wong, C.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Incorporation of particle collisions in the time-dependent Hartree-Fock approximation

In the time-dependent Hartree-Fock (TDHF) approximation, particles interact only through the mean field, and the collisions between particles are not included. Previously, we formulated the extended time-dependent Hartree-Fock (ETDHF) approximation to include particle collisions in terms of a temporal variation of the occupation probability n/sub lambda/ for the single-particle states. In the simplest approximation, the single-particle potential is modified only through the particle density whi… more

Date: January 1, 1982

Creator: Wong, C.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Baryon distribution in relativistic heavy-ion collisions

Recently there has been considerable interest in highly relativistic heavy-ion collisions which was suggested as a way to produce a phase transition from the ordinary confined matter to the unconfined quark-gluon plasma. As the fraction of baryons in the early universe was small, it seems desirable to design a heavy-ion collider such that when the energy density in the central rapidity is high enough for a phase transition, there is no net baryon density there. Recent investigations reveal that… more

Date: January 1, 1984

Creator: Wong, C.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Relativistic Generalization of the Post-Prior Equivalence for Reaction of Composite Particles

In the non-relativistic description of the reaction of composite particles, the reaction matrix is independent of the choice of post or prior forms for the interaction. We generalize this post-prior equivalence to the relativistic reaction of composite particles by using Dirac's constraint dynamics to describe the bound states and the reaction process.

Date: June 4, 2001

Creator: Wong, C.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Signatures of Quark-Gluon Plasma Phase Transition in High-Energy Nuclear Collisions

In high-energy nuclear collisions, the new phase of the quark-gluon plasma is indicated by an anomalous increase in pressure, an excess of direct photon production, an excess of strangeness production, and an anomalous J/{psi} suppression. We review these signatures and discuss how recent high-energy heavy-ion experiments at CERN are consistent with the production of the quark-gluon plasma in high-energy Pb+Pb collisions.

Date: May 22, 2000

Creator: Wong, C.-Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Unresolved questions in J/{psi} production and propagation in nuclei

In order to understand the J/{psi} suppression arising from the possible occurrence of the quark-gluon plasma in high-energy heavy-ion collisions, it is necessary to have a comprehensive picture how the J/{psi} and its precursors are produced, what their properties after production are, and how the J/{psi} and its precursors propagate inside nuclear matter. There are unresolved questions in the descriptions of J/{psi} production and propagation. The author outlines some of these questions and d… more

Date: November 1, 1998

Creator: Wong, C.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

J/{Psi} suppression as a signal for the quark-gluon plasma

The authors review the search for the quark-gluon plasma using the signal of the suppression of J/{psi} production in high-energy heavy-ion collisions. Recent anomalous J/{psi} suppression in high-energy Pb-Pb collisions observed by the NA50 Collaboration are examined and compared with earlier results from pA and nucleus-nucleus collisions with heavy ions of smaller mass numbers. The anomalous suppression of J/{psi} production in Pb-Pb collisions can be explained as due to the occurrence of a n… more

Date: December 1, 1997

Creator: Wong, C.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Possible mechanism of formation and stability of anomalous states of water

The authors examine the physical processes which are involved in the formation and stability of the anomalous states of water reported recently. The initial step of adding a small amount of ionic compound X{sup +}Y{sup {minus}} to pure water leads t the formation of water clusters X{sup +} (H{sub 2}O){sub n} and Y{sup {minus}} (H{sub 2}O){sub n} with n {much_gt} 1. The structure of the cluster around the ion depends sensitively on the equation of state. The authors explore the consequences of p… more

Date: January 1, 1998

Creator: Wong, C.Y. & Lo, S.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Heavy quarkonium production and propagation in nuclei

In the search for the quark-gluon plasma, it has been suggested that the production of charmonium will be suppressed in a quark-gluon plasma because of the screening of the interaction between c and {anti c}. To extract information on the suppression due to the quark-gluon plasma, it is necessary to study the suppression of J/{psi} production by sources different from the quark-gluon plasma. It is therefore useful to examine the mechanism of heavy quarkonium production and its propagation in nu… more

Date: December 31, 1997

Creator: Wong, C.Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department