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3. 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

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

5. 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.

6. 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.

7. 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.

8. 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

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

10. 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 left-right twin Higgs (LRTH) model The LRTH model was first proposed in: Z. Chacko, H. -S. Goh and R. Harnik, JHEP 0601, 108(2006).

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

12. The group structure of the LRTH model:

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

14. Higgs vev:

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

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

17. ～ ～ ～ 100 GeV-200 GeV

18. The relevant couplings: Where

19. 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

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

21. Input parameters used in our calculation:

22. 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.

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

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

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

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

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

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

29. 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.

30. 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.

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

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

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

34. 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. Background At the ILC: Wei Ma, Chong-Xing Yue, Yong-Zhi Wang, Phys.Rev.D79:095010,2009.

35. 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.

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

37. 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.

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

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