LEFT–RIGHT TWIN HIGGS MODEL AND THE SPIN CORRECTION OF TOP-QUARK PAIR PRODUCTION AT ILC

2009 ◽  
Vol 24 (23) ◽  
pp. 4261-4270 ◽  
Author(s):  
YAO-BEI LIU ◽  
SHUAI-WEI WANG

The left–right twin Higgs model predicts the existence of the new neutral gauge boson ZH. In the off-diagonal basis, we explore the effects of extra neutral gauge boson ZH on the spin configuration of the top-quark pair production in the high energy linear e+e- collider (ILC). We find that the new gauge boson ZH exchange can generate significant corrections to the differential cross-sections for the the [Formula: see text] and [Formula: see text] states. Furthermore, when the ZH mass MZH approaches the center-of-mass energy [Formula: see text], the cross-section resonance emerges. We expect that the effects of the new gauge boson ZH on the spin configurations of the top-quark pairs production might be observed in future ILC experiments.

2009 ◽  
Vol 24 (16) ◽  
pp. 1307-1315 ◽  
Author(s):  
YAO-BEI LIU ◽  
XUE-LEI WANG

In the off-diagonal basis, we explore the effects of extra neutral gauge boson Z' predicted in two versions of SU (3)C × SU (3)L × U (1)X model on the spin configuration of the top quark pair production in the high energy linear e+e- collider (ILC). Our numerical results show that, the cross sections for the suppressed spin configurations can be enhanced with the effects of the Z' boson through the modification of the spin configuration by producing enough top quark pairs to be measured in the future ILC experiments, which provides the way to observe the effects of Z' predicted in the 3-3-1 model and discriminate the various versions of 3-3-1 model.


1999 ◽  
Vol 14 (30) ◽  
pp. 2093-2107 ◽  
Author(s):  
A. G. AKEROYD ◽  
A. ARHRIB ◽  
M. CAPDEQUI PEYRANÉRE

We study the associated production of a CP-odd Higgs boson A0 with a neutral gauge boson (Z or photon) in high-energy e+e- collisions at the one-loop level in the framework of two Higgs doublet models (THDM). We find that in the small tan β regime, the top quark loop contribution is enhanced leading to significant cross-sections (about a few fb), while in the large tan β regime the cross-section does not attain observable rates.


2018 ◽  
Vol 182 ◽  
pp. 02052
Author(s):  
Asma Hadef

The Higgs boson was discovered on the 4th of July 2012 with a mass around 125 GeV by ATLAS and CMS experiments at LHC. Determining the Higgs properties (production and decay modes, couplings,...) is an important part of the high-energy physics programme in this decade. A search for the Higgs boson production in association with a top quark pair (tt̄H) at ATLAS [1] is summarized in this paper at an unexplored center-of-mass energy of 13 TeV, which could allow a first direct measurement of the top quark Yukawa coupling and could reveal new physics. The tt̄H analysis in ATLAS is divided into 3 channels according to the Higgs decay modes: H → Hadrons, H → Leptons and H → Photons. The best-fit value of the ratio of observed and Standard Model cross sections of tt̄H production process, using 2015-2016 data and combining all tt̄H final states, is 1:8±0:7, corresponds to 2:8σ (1:8σ) observed (expected) significance.


2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Haiyan Wang ◽  
Bingfang Yang

In the framework of the littlest Higgs Model with T-parity, we discuss the top partner production at future e+e- collider. We calculate the cross sections of the top partner production processes and associated production processes of Higgs and top partner under current constraints. Then, we investigate the observability of the T-odd top partner pair production through the process e+e-→T-T¯-→tt¯AHAH in the tt¯ dilepton channel for two T-odd top partner masses mT-=603  (708) GeV at s=1.5 TeV. We analyze the signal significance depending on the integrated luminosity and find that this signal is promising at the future high energy e+e- collider.


2009 ◽  
Vol 24 (06) ◽  
pp. 463-473 ◽  
Author(s):  
YAO-BEI LIU ◽  
LIN-LIN DU ◽  
QIN CHANG

The left–right twin Higgs (LRTH) model predicts the existence of the new neutral gauge boson Z′. In this paper, we calculate the contributions of this new particle to the processes e+e-→l+l-, [Formula: see text] and [Formula: see text] and study the possibility of detecting this new particle via these processes in the future high-energy linear e+e- collider (LC) experiments with [Formula: see text] and £ int = 340 fb-1, both for unpolarized and polarized beams. We find that the new gauge boson Z′ is most sensitive to the process [Formula: see text] with suitably polarized beams. As long as MZ′ ≤ 1.9 TeV , the absolute value of the relative correction parameter is larger than 5%. We calculate the forward–backward asymmetries for the process [Formula: see text], the results show that the possible signals of Z′ might be detected via measuring the deviations of A FB from its SM prediction for [Formula: see text]. Bounds on Z′ masses are also estimated within 95% confidence level. From our analysis, we conclude that the new gauge boson is most sensitive to the process [Formula: see text] and its virtual effects are most easy to be observed via this process in the future LC experiments.


2015 ◽  
Vol 30 (25) ◽  
pp. 1550125
Author(s):  
Wen Liu ◽  
Wen-Gan Ma ◽  
Lei Guo ◽  
Liang-Wen Chen ◽  
Chang Chen ◽  
...  

We calculate the complete next-to-leading order (NLO) QCD corrections to the [Formula: see text]-odd mirror quark pair [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] production in the littlest Higgs model with [Formula: see text]-parity (LHT) at a high energy [Formula: see text] collider. We present the dependence of the leading order (LO) and NLO QCD corrected cross sections on the colliding energy [Formula: see text]. Our calculation includes the subsequent full weak decays of the final [Formula: see text]-odd mirror quarks by adopting the narrow width approximation and the exclusive 2-jet event selection criterion. We provide the LO and QCD NLO kinematic distributions of final particles. We find that the NLO QCD correction is phase space dependent and modifies the LO cross section evidently. The [Formula: see text]-factor increases noticeably when [Formula: see text] approaches the threshold of the on-shell [Formula: see text]-pair production. We conclude that it is possible to separate the signature of the [Formula: see text]-odd quark pair production from possible Standard Model (SM) background by taking proper kinematic cut.


2006 ◽  
Vol 23 (9) ◽  
pp. 2379-2382 ◽  
Author(s):  
Yue Chong-Xing ◽  
Wang Lei ◽  
Wang Li-Na ◽  
Zhang Yan-Ming

Author(s):  
Anna Kulesza ◽  
Leszek Motyka ◽  
Daniel Schwartländer ◽  
Tomasz Stebel ◽  
Vincent Theeuwes

1987 ◽  
Vol 02 (04) ◽  
pp. 1189-1197
Author(s):  
J.L. Hewett ◽  
T.G. Rizzo

We examine the possibility that heavy lepton pair production can be significantly enhanced by the existence of a new neutral gauge boson, Z’, at SSC energies. We find that in some models, the heavy lepton production cross section resulting from this mechanism exceeds that from production via other scenarios.


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