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Cheuk-Yin Wong

Publications and source records attributed to Cheuk-Yin Wong.

131 records · Page 8Linked to original sources
arXiv1995

Excess Dileptons in High-Energy Nucleus-Nucleus Collisions

It has been observed recently that while continuum dilepton production and open charm production in high-energy $pA$ collisions can be described in terms of the superposition of $pp$ collisions, dilepton yields in S+U collisions are in excess of similar extrapolations. This feature can be explained as arising from the interaction of gluons produced in different soft baryon-baryon collisions, leading to additional open-charm pairs in nucleus-nucleus collisions but not in $pA$ collisions.

hep-ph↗
arXiv1995

Psi' and J/Psi Suppression in High-Energy Nucleon-Nucleus and Nucleus-Nucleus Collisions

The observed features of $ψ'$ to $J/ψ$ suppression in $pA$ and nucleus-nucleus collisions can be explained in terms of a two-component absorption model. For the hard component of the absorption due to the interaction of the produced $c\bar c$ systems with baryons at high relative energies, the absorption cross sections are insensitive to the radii of the $c\bar c$ systems, as described by the Additive Quark Model. For the soft component due to the low energy $c \bar c$ interactions with soft particles produced by other baryon-baryon collisions, the absorption cross sections are greater for $ψ'$ than for $J/ψ$, because the breakup threshold for $ψ'$ is much smaller than for $ψ$.

hep-ph↗
arXiv1995

Enhancement of top production in $e^+ e^- \to t\bar t$

We investigate $e^+ e^- \to t\bar t$ by taking into account wave function distortion effects in the near-threshold region and interpolating the correction factor to the high-energy perturbative QCD region. The strong color attraction between the color singlet $t$ and $\bar t$ enhances the cross section over the tree level results near threshold. The rise of the cross section near the threshold is smoothed by the effects of the large top width and below-threshold resonances. The reliability of the prediction is well assessed by comparing with experimental $R$ ratios for lighter quark production at lower energies. The cross sections obtained here using the reported values of the top mass, can be used directly for New Linear Collider (NLC) projections.

hep-ph↗
arXiv1994

Correction Factors for Reactions involving Quark-Antiquark Annihilation or Production

In reactions with $q \bar q$ production or $q\bar q$ annihilation, initial- and final-state interactions give rise to large corrections to the lowest-order cross sections. We evaluate the correction factor first for low relative kinetic energies by studying the distortion of the relative wave function. We then follow the procedure of Schwinger to interpolate this result with the well-known perturbative QCD vertex correction factors at high energies, to obtain an explicit semi-empirical correction factor applicable to the whole range of energies. The correction factor predicts an enhancement for $q\bar q$ in color-singlet states and a suppression for color-octet states, the effect increasing as the relative velocity decreases. Consequences on dilepton production in the quark-gluon plasma, the Drell-Yan process, and heavy quark production processes are discussed.

hep-ph↗