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Pair production of the scalars from the LRTH model Ma Wei Liaoning Normal University, Dalian Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009. 2010 高能物理学会第八届全国会员代表大会暨学术年会 2010.04.18 南昌

Outline ♥ Motivation ♦ Left-right twin Higgs (LRTH) model ♣ Calculation and results ♠ Discussions

Motivation At the LHC: The hunt for the Higgs bosons is one of the most important goals for the Large Hadron Collider (LHC). Production of the Higgs bosons at the LHC, which will provide a way to test the Higgs boson self-coupling,may be sensitive to new physics.

Motivation At the ILC: In many cases, the ILC can significantly improve the LHC measurements. If a Higgs boson is discovered, it will be crucial to determine its couplings with high accuracy, to understand the so-called echanism of EWSB. The high resolution profile determination of a light Higgs boson (mass, couplings, self-couplings, etc.) can be carried out at the ILC, where clear signals of Higgs events are expected with backgrounds that can be reduced to a magnitude level.

Motivation With the LHC guidance, the ILC will further improve our knowledge of the Higgs boson and help us to understand the nature of its mass.

♦ In some popular physics models beyond the SM Many works have contributed to studies of the Higgs pair production at the hadron collider: ♦ In the SM ♦ Model independently ♦ In some popular physics models beyond the SM

Our work: We study pair production of the scalars from the Left-right twin Higgs (LRTH) model.

The left-right twin Higgs (LRTH) model The details of the model as well as the particle spectrum, Feynman rules, and some phenomenology analysis have been studied in : H. -S. Goh and S. Su, Phys. Rev. D75, 075010(2007)…. The LRTH model was first proposed in: Z. Chacko, H. -S. Goh and R. Harnik, JHEP 0601, 108(2006).

The left-right twin Higgs (LRTH) model ►► The group structure ►► The Higgs fields ►► The new particles ►► The model dependent parameters ►► The relevant couplings

The group structure of the LRTH model:

The Higgs fields of the LRTH model: Two Higgs fields and , are each transforms as (4,1) and (1,4) respectively under the global symmetry.

Higgs vev:

The new particles in the LRTH model: heavy gauge bosons: heavy top quark: neutral Higgs: a pair of charged Higgs: complex Higgs doublet:

The model dependent parameters: Higgs vevs: top quark Yukawa: cut off scale: top quark vector singlet mass mixing parameter: mass parameter: for for and

～ ～ 100 GeV-200 GeV ～

The relevant couplings: Where

Calculation and results I. Pair production of neutral Higgs bosons from the LRTH model at the ILC and LHC. Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009. II. Pair production of the Higgs bosons from the LRTH model via collisions Wei Ma, Chong-Xing Yue, Ting-Ting Zhang, has been submitted

♫ At the LHC: ♪ At the ILC: pair production A. pair production Pair production of neutral Higgs bosons from the LRTH model at the ILC and LHC ♪ At the ILC: pair production A. pair production ♫ At the LHC: B. pair production Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

Input parameters used in our calculation: 100GeV≤M≤200GeV 500GeV≤f≤1500GeV

Pair production of neutral Higgs bosons at the ILC The Feynman diagrams: Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

Numerical results: Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

Pair production of neutral Higgs bosons at the LHC A. pair production Pair production of neutral Higgs bosons at the LHC The Feynman diagrams: Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

Numerical results: Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

B. pair production The Feynman diagrams: Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

Numerical results: Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

II. Pair production of the Higgs bosons from the LRTH model via collisions

Discussions Signal Analysis ►► The branching ratios of the neutral Higgs boson ►► Background Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

The index f corresponds to q and l The charge of the fermion f The branching ratios of the neutral Higgs boson The mass of the SM fermions b, c and The scale parameter The index f corresponds to q and l The charge of the fermion f Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

The branching ratios of the neutral Higgs boson Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

If we assume that the parameter f is in the range of 500GeV ∼ 1500GeV

Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

Background At the ILC: We can see from our numerical results, that the neutral Higgs bosons mainly decay to . If both of the neutral Higgs bosons decay to , then the process can give rise to the final state. There will be events to be generated at the ILC. Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

Therefore, we hope that by using very efficientμ-vertex detectors to tag the b quark jets, we might detect the possible signatures of the neutral Higgs boson via the process in the future ILC experiments. Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

At the LHC: If we assume that one of the neutral Higgs boson decays to and the other decays to , then pair production of the neutral Higgs boson at the LHC can give rise to the final state. There will be several hundreds of events to be generated at the LHC. Furthermore, the narrow peak can be reconstructed to distinguish the signal from the backgrounds. Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

A brief summary In the framework of the left-right twin Higgs model, we study pair production of the neutral Higgs bosons at the International Linear Collider (ILC) and the CERN LHC. Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

A brief summary We find that the production cross section of the process are at the level of several tens fb at the ILC, the production cross section of the pair and pair are at the level of several hundreds fb at the LHC. Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

A brief summary As long as the neutral Higgs boson is not too heavy, we conclude that its pair production might be used to test for the left-right twin Higgs model at the LHC experiment or in the future ILC experiment. Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.