Distinguishing a SM-like MSSM Higgs boson from SM Higgs boson at muon collider

We explore the possibility of distinguishing the SM-like MSSM Higgs boson from the SM Higgs boson via Higgs boson pair production at future muon collider. We study the behavior of the production cross-section in SM and MSSM with Higgs boson mass for various MSSM parameters tan β and m _A . We observe that at fixed CM energy, in the SM, the total cross-section increases with the increase in Higgs boson mass whereas this trend is reversed for the MSSM. The changes that occur for the MSSM in comparison to the SM predictions are quantified in terms of the relative percentage deviation in cross-section. The observed deviations in cross-section for different choices of Higgs boson masses suggest that the measurements of the cross-section could possibly distinguish the SM-like MSSM Higgs boson from the SM Higgs boson.      

Higgs physics at LHC

The large hadron collider (LHC) and its detectors, ATLAS and CMS, are being built to study TeV scale physics, and to fully understand the electroweak symmetry breaking mechanism. The Monte-Carlo simulation results for the standard model and minimal super symmetric standard model Higgs boson searches and parameter measurements are discussed. Emphasis is placed on recent investigations of Higgs produced in association with top quarks and in vector boson fusion channels. These results indicate that Higgs sector can be explored in many channels within a couple of years of LHC operation, i.e.,L = 30 fb⁻¹. Complete coverage including measurements of Higgs parameters can be carried out with full LHC program.     

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。     

Working group report: Collider and B physics

The activities of the working group including some of the seminars are summarized. The written reports received are included.     

The search for Higgs particles at high-energy colliders: Past,present and future

I briefly review the Higgs sector in the standard model (SM) and its minimal aupersymmetric extension, the MSSM. After summarizing the properties of the Higgs bosons and the present experimental constraints, I will discuss the prospects for discovering these particle at the upgraded Tevatron, the large hadron collider (LHC) and a high-energye ⁺ e ⁻ linear collider. The possibility of studying the properties of the Higgs particles will be then summarized.     

大型强子对撞机上的CMS探测器

CMS探测器是大型强子对撞机（LHC）上的4个实验之一,它的设计思想是在质心能量为14TeV及积分亮度为1034 cm-2s-1的条件下对质子-质子对撞进行研究.它的特点是非常紧凑,其μ子室几乎覆盖了4π立体角.另外,CMS探测器还有可提供超强磁场的超导磁铁和由超导磁铁环绕的径迹室以及电磁量能器和强子量能器.CMS探测器对于末态为电子、光子、特别是μ子的物理过程有很好的测量精度.     

Correction of the Littlest Higgs Model to Higgs Production Process e-γ→veW-H in e-γ Collisions

The littlest Higgs model is the most economical one among various little Higgs models. In the context of the littlest Higgs （LH） model, we study the process e-γ → veW^-H and calculate the contributions of the LH model to the cross section of this process. The results show that in most of the parameter spaces preferred by the electroweak precision data, the value of the relative correction is larger than 10%. Such correction to the process e-γ →veW^-H is large enough to be detected via e-γ collisions in the future high energy linear e^＋ e^- collider （ILC） experiment with the c.m. energy √s = 500 GeV and a yearly integrated luminosity ￡ = 100fb^-1, which will give an idea/way to test the model.     

Indirect bounds on heavy scalar masses of the two-Higgs-doublet model in light of recent Higgs boson searches

We study an upper bound on masses of additional scalar bosons from the electroweak precision data and theoretical constraints such as perturbative unitarity and vacuum stability in the two-Higgs-doublet model taking account of recent Higgs boson search results. If the mass of the Standard-Model-like Higgs boson is rather heavy and is outside the allowed region by the electroweak precision data, such a discrepancy should be compensated by contributions from the additional scalar bosons. We show the upper bound on masses of the additional scalar bosons to be about 2 (1) TeV for the mass of the Standard-Model-like Higgs boson to be 240 (500) GeV.     

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.     

Revisiting wrong sign Yukawa coupling of type Ⅱ two-Higgs-doublet model in light of recent LHC data

In light of the recently obtained LHC Higgs data, we examine the parameter space of the type II twoHiggs-doublet model, in which the 125 GeV Higgs bosons exhibit wrong sign Yukawa couplings. Combining the relevant theoretical and experimental limits, we find that the LHC Higgs data exclude most of the parameter space of the wrong sign Yukawa coupling. For m_H 600 GeV, the allowed samples are mainly distributed across several corners and narrow bands of m_A 20 GeV, 30 m_A 120 GeV, 240 GeV m_A 300 GeV, 380 GeV m_A 430 GeV, and480 GeV m_A 550 GeV. For m_A 600 GeV, m_H is required to be lower than 470 GeV. The light pseudo-scalar with a mass of 20 GeV is still permitted in the case of the wrong sign Yukawa coupling of 125 GeV Higgs bosons.     

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 ø⁰ and a pair of charged Higgs bosons ø^±. In this paper, we study two pair production processes of these new particles at the next generation eγ colliders, i.e., e^-γ → e^-ø⁺ø^-, ande^-γ→ ν_Rø^-ø⁰. We find that the production cross section of the process e^-γ →e^-ø⁺ø^- are at the level of several tens fb, the production cross section of the process e^-γ→ν_Rø^-ø⁰ 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.     

Littlest Higgs Model and Higgs Boson Associated Production with Top Quark Pair at High Energy Linear e+e- Collider

In the parameter space allowed by the electroweak precision measurement data, we consider the contributions of the new particles predicted by the littlest Higgs model to the Higgs boson associated production with top quark pair in the future high energy linear e⁺e^- collider (ILC). We find that the contributions mainly come from the new gauge bosons Z_H and B_H. For reasonable values of the free parameters, the absolute value of the relative correction parameter δσ/σ^SM can be significanly large, which might be observed in the future ILC experiment with √{S}=800 GeV.     

Process e-γ→ e-H in Littlest Higgs Model

In the context of the littlest Higgs (LH) model, we estimate the production cross section of the process e-γ→ e-H in the future high-energy linear e e- collider (ILC) with the center-of-mass (CM) energy √S= 500 GeV. Our numerical results show that the contributions of the LH model to this process are very small in most of the parameter space allowed by the electroweak precision measurement data, and are very difficult to be detected in the future ILC experiments.     

Higgs and Bottom Quarks Associated Production at High Energy Colliders in the Littlest Higgs Model with T-Parity

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.     

Higgs bosons in the standard model,the MSSM and beyond

I summarize the basic theory and selected phenomenology for the Higgs boson(s) of the standard model, the minimal supersymmetric model and some extensions thereof, including the next-to-minimal supersymmetric model.     

Higgs and SUSY searches at future colliders

In this talk, I discuss some aspects of Higgs searches at future colliders, particularly comparing and contrasting the capabilities of LHC and next linear collider (NLC), including the aspects of Higgs searches in supersymmetric theories. I will also discuss how the search and study of sparticles other than the Higgs can be used to give information about the parameters of the minimal supersymmetric Standard Model (MSSM).