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Tao Han

Publications and source records attributed to Tao Han.

335 records · Page 19Linked to original sources
arXiv1998

Direct Messenger-Matter Interactions in Gauge-Mediated Supersymmetry Breaking Models

We categorize general messenger and matter interactions in gauge-mediated SUSY breaking models by an R-parity for the messengers and study their phenomenological consequences. The new interactions may induce baryon- and lepton-number violating processes as well as flavor-changing neutral currents. Bounds on the couplings from low-energy data are generally weak due to the large messenger mass suppression, except for the constraint from proton decay. The soft masses for the scalar particles receive negative corrections from the new interactions. Consequently, in certain region of SUSY parameter space the μ-parameter is greatly reduced. The pattern of radiative electroweak symmetry breaking, SUSY particle mass spectrum and decay channels are also affected, leading to observable experimental signature at the current and future colliders.

hep-ph↗
arXiv1998

Strongly-interacting Electroweak Sector At e-e- Colliders

We study the possible experimental signatures resulting from a strongly-interacting electroweak sector at $e^-e^-$ colliders, emphasizing the signal enhancement by high beam polarization. We also discuss the unique role for operating the collider in $e^-γ$ mode to produce a heavy isosinglet vector state $ω_T$.

hep-ph↗
arXiv1998

Higgs Boson and Z Physics at the First Muon Collider

The potential for the Higgs boson and Z-pole physics at the first muon collider is summarized, based on the discussions at the ``Workshop on the Physics at the First Muon Collider and at the Front End of a Muon Collider'' .

hep-ph↗
arXiv1997

Weakly-Coupled Higgs Bosons and Precision Electroweak Physics

We examine the prospects for discovering and elucidating the weakly-coupled Higgs sector at future collider experiments. The Higgs search consists of three phases: (i) discovery of a Higgs candidate, (ii) verification of the Higgs interpretation of the signal, and (iii) precision measurements of Higgs sector properties. The discovery of one Higgs boson with Standard Model properties is not sufficient to expose the underlying structure of the electroweak symmetry breaking dynamics. It is critical to search for evidence for a non-minimal Higgs sector and/or new physics associated with electroweak symmetry breaking dynamics. An improvement in precision electroweak data at future colliders can play a useful role in confirming the theoretical interpretation of the Higgs search results.

hep-ph↗
arXiv1996

Signals for Double Parton Scattering at the Fermilab Tevatron

Four double-parton scattering processes are examined at the Fermilab Tevatron energy. With optimized kinematical cuts and realistic parton level simulation for both signals and backgrounds, we find large samples of four-jet and three-jet+one-photon events with signal to background ratio being 20\%-30\%, and much cleaner signals from two-jet+two-photon and two-jet+$e^+e^-$ final states. The last channel may provide the first unambiguous observation of multiple parton interactions, even with the existing data sample accumulated by the Tevatron collider experiments.

hep-ph↗
arXiv1995

Multiple Interactions in Two-Photon Collisions

We compute cross sections for events where two pairs of partons scatter off each other in the same $γγ$ reaction, giving rise to at least 3 high--{\mbox{$p_T^{}$}} jets. Unlike in {\mbox{$p \bar p$}}\ collisions we find the signal to lie well above the background from higher order QCD processes. If the usual ``eikonaliztion" assumption is correct, the signal should be readily observable at LEP2, and might already be detectable in data taken at TRISTAN.

hep-ph↗
arXiv1995

Triple Electroweak Gauge-Boson Production at Fermilab Tevatron Energies

We calculate the three gauge-boson production in the Standard Model at Fermilab Tevatron energies. At $\sqrt s=2$ TeV in $p\bar p$ collisions, the cross sections for the triple gauge-boson production are typically of order 10 femtobarns (fb). For the pure leptonic final states from the gauge-boson decays and with some minimal cuts on final state photons, the cross sections for $p \bar p \rightarrow W^\pm γγ, Zγγ$ and $W^+W^- γ$ processes are of order a few fb, resulting in a few dozen clean leptonic events for an integrated luminosity of 10 fb$^{-1}$. The pure leptonic modes from other gauge-boson channels give significantly smaller rate. Especially, the trilepton modes from $W^+W^-W^\pm$ and $t \bar t W^\pm \rightarrow W^+W^-W^\pm$ yield a cross section of order 0.1 fb if there is no significant Higgs boson contribution. For a Higgs boson with $m_H^{} \simeq 2M_Z^{}$, the triple massive-gauge-boson production rate could be enhanced by a factor of $4-6$.

hep-ph↗
arXiv1993

Strongly-Interacting Electroweak Sector at Future Colliders

If there are no light Higgs bosons found below $\cal O$(800 GeV) or so, the interactions among longitudinally-polarized vector bosons ($\wl$) will become strong at the TeV region, and new physics that is responsible for the electroweak symmetry breaking must emerge at this energy scale. We discuss the phenomenological prospects of the Strongly-interacting Electro-Weak Sector (SEWS) at future TeV linear colliders and hadronic supercolliders.

hep-ph↗
arXiv1993

Heavy Top Quark Searches in the Di-Lepton Mode at the Tevatron

We present the results of a detailed study of the effects of $b$-tagging on the heavy top-quark signal and backgrounds for the modes of the di-lepton plus two high transverse energy jets at the Fermilab Tevatron. The general characteristics of the heavy top-quark signal events are also discussed so that a comparison can be made between $b$-tagging and imposing stringent kinematical cuts to eliminate backgrounds.

hep-ph↗