Pair production of neutral Higgs bosons from the left-right twin Higgs model via γγ collisions

The left-right twin Higgs (LRTH) model predicts the existence of the neutral Higgs bosons (h, Φ⁰), which can be produced in pairs (Φ⁰Φ⁰, hh, Φ⁰h) via γγ collisions at the next generation e⁺e^- International Linear Collider (ILC). Our numerical results show that the production cross section of the neutral Higgs boson pair Φ⁰Φ⁰ can reach 8.8 fb. The subprocess γγ→Φ⁰Φ⁰ might be used to test the LRTH model in future ILC experiments.     

Production of Charged Higgs Bosons from Left-Right Twin Higgs Model at TeV Energy e-γ Colliders

The left-right twin Higgs （LRTH） model predicts the existence of three additional Higgs bosons： one neutral Higgs φo and a pair of charged Higgs bosons φ±. In this paper, we study two pair production processes of these new particles at the next generation eγ colliders, i.e., e-γ → e-φ＋φ- , and e-γ→vRφ-φ0. We find that the production cross section of the process e-γ → e-φ＋φ- are at the level of several tens fb, the production cross section of the process e-γ→vRφ-φ0 can reach 0.35 fb with the reasonable parameter values. As long as the charged Higgs bosons are not too heavy, we conclude that these processes might be used to test for the left-right twin Higgs model in future high-energy linear collider experiments.     

国际直线对撞机研究现状及未来发展

文章介绍了国际直线对撞机(ILC)的科学目标及直线对撞机(LC)与强子对撞机(LHC)的关系.结合对正负电子直线对撞机历史的回顾及国际直线对撞机方案的选择,对国际直线对撞机的发展现状及未来发展趋势进行了介绍.对中国科学家在国际直线对撞机中所做的国际合作研究进行了简要的回顾,并强调了中国抓住国际直线对撞机国际合作机遇对中国科学发展的重要性.     

希格斯粒子之理论浅析

被誉为上帝粒子的希格斯玻色子于2012年7月4日在欧洲核子研究中心的大型强子对撞机(LHC)上被发现,这一发现震惊了世界。文章将从理论方面介绍希格斯玻色子,内容包括:(1)世界的基本组分和希格斯玻色子在其中扮演的角色;(2)希格斯玻色子的本质和希格斯机制;(3)希格斯玻色子在LHC上的产生、衰变和发现;(4)希格斯玻色子存在的和谐社会——超对称理论。     

τ轻子的发现和电子反中微子的首次观察：1995年诺贝尔物理奖介绍

美国物理学家马丁·珀尔（Ｍａｒｔｉｎ Ｐｅｒｌ）和弗雷德里克·雷恩斯（Ｆｒｅｄｒｉｃｋ Ｒｅｉｎｅｓ）共同获得了１９９５年诺贝尔物理奖．珀尔及其合作者于７０年代间发现了τ轻子，雷思斯与已故的克拉埃德·考温（Ｃｌｙｄｅ Ｃｏｗａｎ）于５０年代间首次成功地观察到电子反中微子．他们在轻子研究方面的先驱性工作为建立轻子－夸克层次上的物质结构图像作出了重大贡献．     

希格斯粒子之理论浅析

被誉为上帝粒子的希格斯玻色子于2012年7月4日在欧洲核子研究中心的大型强子对撞机(LHC)上被发现,这一发现震惊了世界。文章将从理论方面介绍希格斯玻色子,内容包括：(1)世界的基本组分和希格斯玻色子在其中扮演的角色;(2)希格斯玻色子的本质和希格斯机制;(3)希格斯玻色子在LHC上的产生、衰变和发现;(4)希格斯玻色子存在的和谐社会——超对称理论。     

有希望发现希格斯玻色子

据英因New Scientist（13Jan．2007），5报道：从新测定之传递弱相互作用的一种w玻色子的质量推断，利用将于今年启用的一台新粒子对撞机有希望发现希格斯粒子．希格斯玻色子（Higgsboson）对于回答“什么是质量”这个问题至关重要，尽管一直未被发现，但粒子物理学的标准模型预言w玻色子、“顶”夸克和希格斯玻色子三者的质量之间有一定联系．     

μ子对撞机的研究进展

μ子对撞机的研究进展目前，理论方面认定，“超标准模型”新物理将出现在ＴｅＶ量级或接近ＴｅＶ量级能量的夸克－反夸克和轻子－反轻子对撞中．为了充分研究ＴｅＶ能级物理，至少要有一台几个ＴｅＶ能量的强子－强子对撞机，用来广泛寻找新物理，还需一台或更多的ＴｅＶ...     

国际直线对撞机研究现状及未来发展

文章介绍了国际直线对撞机(ILC)的科学目标及直线对撞机(LC)与强子对撞机（LHC）的关系.结合对正负电子直线对撞机历史的回顾及国际直线对撞机方案的选择,对国际直线对撞机的发展现状及未来发展趋势进行了介绍.对中国科学家在国际直线对撞机中所做的国际合作研究进行了简要的回顾,并强调了中国抓住国际直线对撞机国际合作机遇对中国科学发展的重要性.     

Tau Leptonic Decay τ→lVlVτ in Littlest Higgs Model＊

We consider the τ leptonic decay $\tau\rightarrow l\bar{\nu}_{l}\nu_{\tau}$ in the framework of the littlest Higgs (LH) model and calculate the corrections of new particles to this decay. We find that the contributions of the charged scalars can be safely ignored and the LH model is in perfect agreement with the universality of the couplings of the SU gauge bosons to the leptonic charged currents. The corrections of the LH model to the τ leptonic decay $\tau\rightarrow l\bar{\nu}_{l}\nu_{\tau}$ are not sensitive to the parameter c, but depend strongly on the parameters f and x. The precision measured data about the τ leptonic decay demand that the parameter f approximately equal 3.5 TeV and x>0.1, while agree with the general expectation based on other phenomenological explorations.     

Production of Charged Higgs Boson Associated with Top Partner at the Large Hadron Collider

In the context of the littlest Higgs （LH） model and the left-right twin Higgs （LRTH） model, we study the production of charged Higgs boson associated with top partner at the LHC. We find that, in the LH model, its cross section can be significantly larger for the scale parameter f = 500 GeV, while sharply decreases as f increases. In the LRTH model, this production process mainly transfers to the t？tb？bb final state at the Large Hadron Collider and its production rate can reach 167.2 fb.     

在T2HDM模型中中性希格斯粒子对B→X_s1 1-衰变过程的影响(英文)

在T2HDM模型中计算了中性希格斯粒子圈图对稀有衰变过程B→X_s1 1-的贡献.通过计算发现:(a)中性希格斯粒子对衰变过程B→X_s1 1-的修正能够增强其标准模型的预言,但增幅很小;(b)在中性希格斯玻色子的质量大于100GeV和tanβ<40的情况下,中性希格斯粒子对稀有衰变过程B→X_s1 1-的分支比的贡献可忽略.     

在T2HDM模型中中性希格斯粒子对B→Xsl+l－衰变过程的影响

在T2HDM模型中计算了中性希格斯粒子圈图对稀有衰变过程B→X_sl⁺l^－的贡献. 通过计算发现: (a)中性希格斯粒子对衰变过程B→X_sl⁺l^－的修正能够增强其标准模型的预言, 但增幅很小; (b)在中性希格斯玻色子的质量大于100GeV和tanβ<40的情况下, 中性希格斯粒子对稀有衰变过程B→X_sl⁺l^－的分支比的贡献可忽略.     

Lepton-number-violating decays of singly-charged Higgs bosons in the type-（Ⅰ＋Ⅱ ） seesaw model

The lepton-number-violating decays of singly-charged Higgs bosons H^± are investigated in the minimal type-（ Ⅰ＋Ⅱ ） seesaw model with one SU（2）L Higgs triplet △ and one heavy Majorana neutrino N1 at the TeV scale. We find that the branching ratios B（H^＋ → 1α^＋υ^-） （for α = e,μ,τ） depend not only on the mass and mixing parameters of three light neutrinos υi （for i = 1, 2, 3） but also on those of N1. Assuming that the mass of N1 lies in the range of 200 GeV to 1 TeV, we figure out the generous interference bands for the contributions of υi and N1 to B（H^＋→ 1α^＋υ^-）. We illustrate some salient features of such interference effects by considering three typical mass patterns of υi, and show that the relevant Majorana CP-violating phases can affect the magnitudes of B（H^＋→ 1α^＋υ^-）） in this parameter region.     

ILC——TeV能量正负电子直线对撞机计划

 2004年8月20日,在北京举行的第32届世界高能物理大会结束的前两天,国际未来加速器委员会(ICFA)主席乔纳森·多芬(JonathanDorfan)在大会上宣布:国际未来加速器委员会已经批准了国际技术推荐专家委员会(InternationalTechnologyRecommendationPanel)的推荐,专家委员会正式推荐在未来的正负电子直线对撞机上采用"冷技术"。     

Charged Higgs Pair Production in a General Two Higgs Doublet Model at e^＋e^- and μ^＋μ^- Linear Colliders

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.     

Lepton Flavor Violating Z →lIlJ in SO（3） Gauge Extension of SM

The SO（3） gauge extension of SM, which is proposed to present a successful explanation for the observed small masses of neutrino and the nearly tri-bimaximal neutrino mixing, predicted the vector-like SO（3） triplet Majorana neutrinos and SUL（2） double Higgs bosons. In this work we calculate branching ratios of the charged lepton flavor violating decays lIlJV （V = γ, Z） induced by these Majorana neutrinos and Higgs bosons. We find that under the model parameters constrained by experimental bounds on the decays Z →lIlJ, the branching ratio of decays lI→lJγ can be up to 10^-10, which may be accessible at the future experiments.     

高能加速器近期的几个大工程

 量子论和相对论的发现和确立是20世纪基础科学的最伟大的事件,它们是现代科学技术的基础,改变了整个人类的生活方式。例如,人们制造了原子弹、氢弹,建造了核电站;随着集成电路的迅速发展,计算机已经普及到家庭,人们坐在家里就可通过网络了解全世界发生的事。20世纪后期,在总结新的实验事实的基础上,理论上创立了粒子物理的标准模型,所有核物理和粒子物理的实验结果都和标准模型的预言相一致。在人们为标准模型而欢呼的时候,实验上测量到存在中微子振荡现象,说明中微子有质量,这就超出了标准模型,说明标准模型需要完善和发展。