arXiv subjects

Wai-Yee Keung

Publications and source records attributed to Wai-Yee Keung.

95 records · Page 6Linked to original sources

arXiv1996

Color-Octet $J/ψ$ Production in the $Υ$ Decay

The direct production rate of $ψ$ in the $Υ$ decay is shown to be dominated by the process $ Υ\to ggg^*$ followed by $g^* \to ψ$ via the color-octet mechanism proposed recently to explain the anomalous prompt charmonium production at the Tevatron. We show that this plausibly dominant process has a branching ratio compatible with the experimental data. Further experimental study in this channel is important to test the significance of the color-octet component of $c\bar c$ pair inside the $ψ$ system.

hep-ph↗

arXiv1996

Solutions to the R_b, R_c and alpha_s puzzles by Vector Fermions

We propose two minimal extensions of Standard Model, both of which can easily accommodate the recent puzzling observations about the excess in $R_b$, the deficit in $R_c$ and the discrepancy in the low energy and high energy determinations of $α_{s}$. Each model requires three additional heavy vectorial fermions in order to resolve the puzzles. The current phenomenological constraints and the new potential phenomena are also discussed.

hep-ph↗

arXiv1995

Color-Octet Quarkonium Production at the $Z$ Pole

The direct production rate of $J/ψ$ via the color-octet mechanism is calculated at the $Z$ resonance. The color-octet production process $Z\to J/ψq \bar q$ is shown to have a substantial branching ratio as well as a distinctive energy spectrum, which can be used as a powerful tool to distinguish from the color-singlet direct production of the $J/ψ$.

hep-ph↗

arXiv1994

CP violation in the cubic coupling of neutral gauge bosons

We investigate the CP violating form factor of the ZZZ$ and $ZZγ$ vertices in the pair production of $Z^0$ bosons. Useful observables in azimuthal distributions are constructed to probe $CP$ nonconservation which may originate from these vertices. A simple Two Higgs Model of $CP$ violation is used as an illustration.

hep-ph↗

arXiv1992

CP violation in top pair production at an e^+e^- collider

We investigate a possible CP violating effect in $e^+e^-$ annihilation into $t\bar t$ top quark pairs. As an illustrative example, we assume the source of the CP nonconservation is in the Yukawa couplings of a neutral Higgs boson which contain both scalar and pseudoscalar pieces. One of the interesting observable effects is the difference in production rates between the two CP conjugate polarized $t\bar t$ states.

hep-ph↗