Browsing by Author "Hou, WS"

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Flavor-changing neutral Higgs boson couplings and top-quark-charm-quark production at the Next Linear Collider
(1997-12-01)
Hou, WS
;
Lin, GL
;
Ma, CY
;
電子物理學系
;
物理研究所
We explore the possibility of detecting flavor-changing neutral Higgs boson couplings at the Next Linear Collider (NLC) through e(+)e(-)->nu(e)<(nu)over bar>(e)t (c) over bar. In the framework of a general two-Higgs-doublet model, we perform a complete calculation and find that sigma(e(+)e(-)-->nu(e) nu(e)t (c) over bar nu(e)<(nu)over bar>(e) (t) over bar c) could reach similar to 9 fb for root s=2 TeV. This amounts to an annual production of 500 t (c) over bar plus (t) over bar c pairs at the NLC with an integrated luminosity of 50 fb(-1). The dependence of the tc-production rate on the neutral scalar mixing angle is mild except when sin(2) alpha-->0 or 1. The nu nu W+W- background should be manageable after b tagging, while vvt (t) over bar background should not be a problem when the signal event rate is still interesting. The process, together with e(+)e(-)-->nu(e)<(nu(e))over bar>W+W-,nu(e)<(nu(e))over bar>ZZ studies, offer the chance of measuring the t-c-Higgs-bsson coupling.
Flavor-changing neutral Higgs boson couplings and top-quark-charm-quark production at the Next Linear Collider
(1997-12-01)
Hou, WS
;
Lin, GL
;
Ma, CY
;
電子物理學系
;
物理研究所
We explore the possibility of detecting flavor-changing neutral Higgs boson couplings at the Next Linear Collider (NLC) through e(+)e(-)->nu(e)<(nu)over bar>(e)t (c) over bar. In the framework of a general two-Higgs-doublet model, we perform a complete calculation and find that sigma(e(+)e(-)-->nu(e) nu(e)t (c) over bar nu(e)<(nu)over bar>(e) (t) over bar c) could reach similar to 9 fb for root s=2 TeV. This amounts to an annual production of 500 t (c) over bar plus (t) over bar c pairs at the NLC with an integrated luminosity of 50 fb(-1). The dependence of the tc-production rate on the neutral scalar mixing angle is mild except when sin(2) alpha-->0 or 1. The nu nu W+W- background should be manageable after b tagging, while vvt (t) over bar background should not be a problem when the signal event rate is still interesting. The process, together with e(+)e(-)-->nu(e)<(nu(e))over bar>W+W-,nu(e)<(nu(e))over bar>ZZ studies, offer the chance of measuring the t-c-Higgs-bsson coupling.
Like sign top quark pair production at linear colliders
(1996-06-27)
Hou, WS
;
Lin, GL
;
物理研究所
;
Institute of Physics
In the general two Higgs doublet model with flavor changing neutral Higgs couplings, neutral Higgs bosons may decay dominantly via or <(t)over bar c> final states. At the linear collider, e(+)e(-) --> h(0)A(0) or H(0)A(0) production processes may result in , W+W- t (c) over bar or tt (c) over bar (c) over bar (or (t) over bar (t) over bar cc) final states. The process yy --> h(0), A(0) --> t (c) over bar is also promising, but e(+)e(-) --> (h(0), H-0)Z(0) --> is relatively suppressed. The possibility of observing like sign lepton pairs, usually the hallmark for neutral meson mixing, is quite interesting since T-0 mesons do not even form.
Pev cosmic neutrinos from the mountains
(2004-05-30)
Yeh, P
;
Athar, H
;
La Barbera, N
;
Bouaissi, S
;
Catalano, O
The NuTel collaboration is building a wide field-of-view Cerenkov telescope to be installed on a mountain site for observing near horizontal air showers emerging from another mountain. Cosmic tau neutrinos is the primary source of such showers. This technique will be realized for the first time in the v, energy range of 2 PeV to 1000 PeV. The telescope has enough sensitivity to observe cosmic neutrinos from sources like Active Galactic Nuclei and Galactic Center assuming fluxes from current theoretical models.
Probing flavor changing neutral Higgs couplings at LHC
(1997-09-18)
Hou, WS
;
Lin, GL
;
Ma, CY
;
Yuan, CP
;
電子物理學系
Uniquely heavy with mass at the weak scale, the top quark may have large flavor changing couplings to Higgs bosons that are as yet unexplored. We show that such couplings could be directly probed at the LHC through the parton subprocess c((c) over bar)g --> t((t) over bar)A(0), where the pseudoscalar A(0) subsequently decays into t (c) over bar or (t) over bar c, giving rise to the intriguing final state of like sign top quark pairs. After demanding l(+/-)l(+/-), missing energy and two b-jets, the major background turns out to be q (q) over bar' --> Wt (t) over bar, which can be partially suppressed by jet counting. The signal can then manifest itself in the asymmetry of numbers of l(+)l(+) and l(-)l(-) events. To further improve the signal over background, efficient t vs. (t) over bar tagging methods should be developed. (C) 1997 Elsevier Science B.V.
Probing flavor changing neutral Higgs couplings at LHC
(1997-09-18)
Hou, WS
;
Lin, GL
;
Ma, CY
;
Yuan, CP
;
電子物理學系
Uniquely heavy with mass at the weak scale, the top quark may have large flavor changing couplings to Higgs bosons that are as yet unexplored. We show that such couplings could be directly probed at the LHC through the parton subprocess c((c) over bar)g --> t((t) over bar)A(0), where the pseudoscalar A(0) subsequently decays into t (c) over bar or (t) over bar c, giving rise to the intriguing final state of like sign top quark pairs. After demanding l(+/-)l(+/-), missing energy and two b-jets, the major background turns out to be q (q) over bar' --> Wt (t) over bar, which can be partially suppressed by jet counting. The signal can then manifest itself in the asymmetry of numbers of l(+)l(+) and l(-)l(-) events. To further improve the signal over background, efficient t vs. (t) over bar tagging methods should be developed. (C) 1997 Elsevier Science B.V.