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1.
In the littlest Higgs Model with T-parity,we discuss the Higgs production in association with bottom quarks at the LHC and future electron-positron collider.We calculate the cross sections of production channels pp→bb H,bb→H and bg→b H at 14 Te V LHC and the cross sections of production channel e~+e~-→bb H in(un)polarized beams at the lowest order.In order to investigate the observability,we display some typical final state distributions in the Higgs to diphoton channel.  相似文献   

2.
We perform the precision calculations for the e+e-→q_q_(q_q_=u_u_, c_c_, d_d_,s_s_) processes up to the QCD next-to-leading order (NLO) including full weak decays for the final T-odd mirror quarks in the littlest Higgs model with T-parity (LHT) at the Compact Linear Collider (CLIC). We show the dependence of the leading order (LO) and NLO QCD corrected cross sections on the colliding energy √s, and provide the LO and QCD NLO kinematic distributions of final particles. The results show that the LO cross section can be enhanced by the NLO QCD correction and the K-factor increases obviously when the threshold of the on-shell q_q_-pair production approaches the colliding energy √s. The K-factor value varies in the range of 1.04 ~ 1.41 in our chosen parameter space. We find that a simple approximation of multiplying the LO kinematic distribution with the integrated K-factor is not appropriate for precision study of the e+e-→q_q_(q_q_=u_u_, c_c_, d_d_,s_s_) processes, since the NLO QCD corrections are phase space dependent. It is necessary to calculate the differential cross sections including full NLO QCD corrections to get reliable results.  相似文献   

3.
The littlest Higgs (LH) model is the most economical one among various little Higgs models, which predicts the existence of the charged scalars Φ^±. In this paper, we study the production of the charged Higgs boson Φ^- with single top quark via the process gb →tΦ^- at the CERN Large Hadron Collider (LHC). The numerical results show that the production cross section is sma/ler than 0.2 pb in most of the parameters space, it is very difficult to observe the signatures of the charged scalars via the process pp → gb + X → tΦ^- + X at the LHC experiments. However, it can open a window to distinguish the top-pions in the TC2 model or charged Higgs in the MSSM from Φ^±.  相似文献   

4.
在最小Higgs模型(LH)框架内讨论了Higgs粒子产生过程e+e-→ZH.结果表明,对该过程的修正效应主要来自重光子A′,但如果自由参数c取值范围为0.85—1,则重规范玻色子Z′的贡献就不能忽略.在LH模型大部分参数空间内,过程e+e-→ZH的总产生截面σtot与标准模型(SM)相应值的偏差大于5%,应该能在未来的高能e+e–对撞机(LC)实验中观测到  相似文献   

5.
The twin Higgs mechanism has recently been proposed to solve the little hierarchy problem. In the context of the left-right twin Higgs (LRTH) model, we discuss single production of the new charged gauge boson WH^- , which is predicted by the left-right twin Higgs model, in association with top quark at the CERN Large Hadron Collider (LHC). It is found that, for a typical nonzero value of mass mixing parameter M = 150 GeV in the LRTH model, the production cross section is in the range of 3 ×10^-2 - 6.07×10^3 fb at the LHC. As long as the WH^- is not too heavy, the possible signatures of the heavy charged gauge boson might be detected at the LHC experiments.  相似文献   

6.
In the framework of topcolor-assisted technicolor model we calculate the contributions from the preudo Goldstone bosons and new gauge bosons to e^ e^-→ttk.We find that for reasonable ranges of the parameters,the preudo Goldstone bosons afford dominate contribution,the correction arising from new gauge bosons is negligibly small,the maximum of the relative corrections is-10% with the center-of-mass energy √s=500GeV;whereas in the case of √s=1500 GeV,the relative corrections could be up to 16%.Thus large new physics might be observable at the experiments of next-generation linear colliders.  相似文献   

7.
M.  Hashemi 《理论物理通讯》2014,61(1):69-74
In this paper, charged Higgs pair production through l^+l^- → H^+ H^-, where l = e or μ, is studied within the framework of a general Two Higgs Doublet Model (2HDM). The analysis is relevant to a future e^+e^- or μ^+ μ^- collider operating at center of mass energy of √s = 500 GeV. Two different scenarios of small and large a values are studied. Here a is the parameter, which diagonMizes the neutral CP-even Higgs boson mass matrix. Within the Minimal Supersymmetric Standard Model (MSSM), cross section of this process is almost the same at e+ e- and #+#- colliders. It is shown that at e^+e^- eolliders within a general 2HDM, cross section is not sensitive to the mass of neutral Higgs bosons, however, it can acquire large values up to several picobarn at μ^+μ^- colliders with the presence of heavy neutral Higgs bosons. A scan over Higgs boson mass parameter space is performed to analyze the effect of large masses of neutral Higgs bosons involved in the s-channel propagator and thus in the total cross section of this process.  相似文献   

8.
The littlest Higgs model with T-parity, which is called LHT model, predicts the existence of the new particles, such as heavy top quarks, heavy gauge bosons, and mirror fermions. We calculate the one-loop contributions of these new particles to the top quark ehromomagnetic dipole moment (CMDM) AK. We find that the contribution of the LHT model is one order of magnitude smaller than the standard model prediction value.  相似文献   

9.
The littlest Higgs model with T-parity, which is called LHT model, predicts the existence of the new particles, such as heavy top quarks, heavy gauge bosons, and mirror fermions. We calculate the one-loop contributions of these new particles to the top quark chromomagnetic dipole moment (CMDM) ΔK. We find that the contribution of the LHT model is one order of magnitude smaller than the standard model prediction value.  相似文献   

10.
We investigate the spin correlations in top quark pair production near the threshold at the e e- linear collider. Comparing with the results above the threshold region, we find that near the threshold region the off-diagonal basis, the optimized decomposition of the top quark spins above the threshold region, does not exist, and the beamline basis is the optimal basis, in which there are the dominant spin components: the up-down (UD) component for e-Le scattering and the down-up (DU) component for e-Re scattering can make up more than 50% of the total cross section,respectively.  相似文献   

11.
We investigate the spin correlations in top quark pair production near the threshold at the e^ e^- linear collider. Comparing with the results above the threshold region, we find that near the threshold region the off-diagonal basis, the optimized decomposition of the top quark spins above the threshold region, does not exist, and the beamline basis is the optimal basis, in which there are the dominant spin components: the up-down (UD) component for e^-le^ scattering and the down-up (DU) component for eR^-e^ scattering can make up more than 50% of the total cross section,respectively.  相似文献   

12.
13.
In the littlest Higgs model with T-parity (LHT) the mirror quarks induce the special flavor structures and some new flavor-changing couplings, which could greatly enhance the production rates of the flavor-changing processes. We in this paper study some bottom and anti-strange production processes in the LHT model at the International Linear Collider (ILC), i.e.,e+e- →b\bar{s} andγγ→b\bar{s}. The results show that the production rates of these processes are sizeable for the favorable values of the parameters. Therefore, it is quite possible to test the LHT model or make some constraints on the relevant parameters of the LHT through the detection of these processes at the ILC.  相似文献   

14.
With the high energy and luminosity, the planned ILC has the considerable capability to probe the new heavy particles predicted by the new physics models. In this paper, we study the potential to discover the lightest new gauge boson BH of the Littlest Higgs model via the processes e+e- →γ(Z)BH at the ILC. The results show that the production rates of these two processes are large enough to detect BH in a wide range of the parameter spaces, specially for the process e+e- →γBH. Furthermore, there exist some decay modes for BH which can provide the typical signal and clean backgrounds. Therefore, the new gauge boson BH should be observable via these production processes with the running of the ILC if it exist.  相似文献   

15.
在最小Higgs模型和T宇称下的最小Higgs模型中, 计算了单个顶夸克的产生 过程eγ→νebt的产生截面, 并讨论了这两种模型对该过程产生截面的贡献. 发现在合适的参数范围内, 来自T宇称下的最小Higgs模型中对Wtb耦合的修正项对该过程产生截面的相对修正大于5%,这种影响能在将来的直线对撞机实验中探测到. 然而, 在最小Higgs模型中, 新的规范玻色子W±H对该过程的贡献非常小.  相似文献   

16.
We investigated the neutral Higgs boson pair production at the CERN Large Hadron Collider (LHC) in the SM with four families. We found that the gluon-gluon fusion mode is the most dominant one in producing neutral Higgs boson pair at the LHC, and it can be used to probe the trilinear Higgs coupling. If the heavy quarks of the fourth generation really exist within the SM, they can manifest their effect on the cross section of the Higgs pair production process at the LHC. Our numerical results show that there will be 2×104 neutral Higgs boson pair production events per year if the next generation heavy quarks really exist, while there will be only 2×103 events produced per year if there are only three families in the SM.  相似文献   

17.
18.
计划中的高能量、高亮度对撞机ILC在寻找新物理模型所预言的新的重粒子方面具有很大的潜力。本文,我们研究了在ILC上,通过过程e^+e^- ->r(Z)B_H发现littlest Higgs模型中最轻的新规范玻色子B_H的可能性。结果显示,在较大的参数空间范围,这两个过程都有较大的产生截面,能产生足够的信号探测B_H,尤其是对过程e^+e^- ->rB_H。另外,B_H的一些衰变道可以产生特征比较明显背景比较干净的信号。如果B_H存在,随着ILC的运行,新的规范玻色子B_H应能通过这两过程观测。  相似文献   

19.
The existence of a new coloured vector-like heavy fermion T is a crucial prediction in little Higgs models, which play a key role in breaking the electroweak symmetry. The littlest Higgs model is the most economical one among various little Higgs models. In the context of the littlest Higgs model, we study single production of the new heavy vector-like quark and discuss the possibility of detecting this new particle in the future LC experiment. It is found thai, the production cross section is in the range of 1.7× 10^-3 - 30 fb at TeV energy electron-photon collider with √s- 3 TeV and a yearly integrated luminosity of ,£ = 500 fb^-1.  相似文献   

20.
The CP-violating effects to the subprocess gg → H H- are studied in the mSUGRA scenario at the CERN large hadron collider, by taking into account the experimental bounds of electron and neutron electric dipole moments.The CP-violating effects in this process are related to the complex phases ofμ and Af in the mSUGRA scenario. In our calculation we consider smallCP phases ofμ and Af and neglect the effects of neutral Higgs boson mixing. In this case the CP effects to the process mainly come from the complex couplings of Higgs-squark-squark. We find a strong dependence of charged Higgs boson pair production rate on the complex couplings in the parameter space of minimal supersymmetric standard model``  相似文献   

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