Light Higgs Production in Two Higgs Doublets Models type III

Transcription

1 Light Higgs Production in Two Higgs Doublets Models type III Camilo Andrés Jiménez-Cruz (M.Sc. Student), J.-Alexis Rodríguez López, Roberto Martinez Universidad Nacional de Colombia December 5, 2007

2 Abstract By using the Cheng, Sher and Yuan s anzats, we study the light Higgs Boson production associated with b quark production at TEVATRON using the 2HDM type III. We compare the simulations with experimental results coming from TEVATRON, finding valid ranges for the bb coupling. By using these results, we calculate the cross section for the process pp b bh(b b) for the LHC collider. The relative importance of these channels could give an important evidence of new physics in this experiment.

3 Outline Introduction Two Higgs Doublet Model type III (2HDM-III) Associated h 0 b b production Results Concluding Remarks References

4 Outline Introduction Two Higgs Doublet Model type III (2HDM-III) Associated h 0 b b production Results Concluding Remarks References

5 Introduction Standard Model Although a relatively light Higgs coming from the SM can support the idea of the SM being true all the way to the Plank scale, most theorists consider such a possibility unlikely[1].

6 Introduction Light Higgs A light Higgs boson is preferred by precision fits of the Standard Model (SM) and also theoretically required by many frameworks that can be effectively SM-like at low energies. The production of a Higgs boson in association with a heavy quark and antiquark pair, both t t and b b at hadron colliders will be sensitive to the Higgs-fermion couplings and can help discriminate between models.

7 Introduction Two Higgs Doublet Models One of such theories is the so-called 2HDM, which includes a second scalar doublet with the same properties of the first one.

8 Outline Introduction Two Higgs Doublet Model type III (2HDM-III) Associated h 0 b b production Results Concluding Remarks References

9 Model 2HDM Construction The 2HDM includes a second scalar doublet, with each doublet acquiring a vacuum expectation value different from zero. This is Φ i = ( φ + i φ 0 i ), Φ i = ( 0 v i 2 ), i = 1, 2

10 Model 2HDM Construction The scalar spectrum of mass eigenvalues contains two CP-even neutral Higgs bosons (h 0, H 0 ) coming from the mixing of the real part of the neutral components of both doublets with a mixing angle α; two charged Higgs bosons (H ± ), which mix with the would-be Goldstone bosons (G ± W ) through the mixing angle tan β = v 2 /v 1 and one CP-odd Higgs (A 0 ), which mixes with the neutral would-be Goldstone.

11 Model Yukawa Lagrangian The most general Lagrangian that can be written in this kind of models includes interactions between all the fermions and both doublets: L Y = η U,0 ij Q 0 il Φ 1 U 0 jr + η D,0 ij + ξ U,0 ij Q 0 Φ il 2 UjR 0 + ξ D,0 ij + l.s. + h.c Q 0 il Φ 1 D 0 jr Q 0 il Φ 2 D 0 jr

12 Model Yukawa Lagrangian The strong suppression of FCNC at three level makes customary to impose discrete symmetries over the doublets. These symmetries end in one of three types of models[2]. Type I Φ 1 is the responsible of giving mass to the matter, while Φ 2 decouples totally from them. Type II Φ 1 couples to the up sector while Φ 2 couples to the down sector. This is the case of the MSSM. Type III Both doublets couple to both sectors.

13 Model 2HDM-III As there are two non-diagonal 3 3 matrices and the suffix 0 means that these fermion states are not mass eigenstates. It is clear that the mass terms for the matter will depend on two Yukawa coupling matrices. The rotation of the quarks and leptons allow us to diagonalize one of the matrices but in general not both simultaneously, then one Yukawa coupling remains non-diagonal, leading to the FCNC at tree level.

14 Model Cheng, Sher and Yuan s Anzats (CSY) In this work, we use the CSY parameterization of the Yukawa s couplings[5]. This anzats is based on the SM φf f couplings and states that ξ ij mi m j λ ij v This is an ansatz for the Yukawa texture matrices looking for a phenomenological similarity with SM couplings.

15 Model Restrictions over λ ij Some restrictions over the λ ij and the ξ ij parameter sets have been found[4] Parameter Range ξµτ 2 [ ; ] ξ ττ [ ; 2, ] ξ µµ [-0.12;0.12] ξ µe [-0.39;0.39] λ bb [-100;100] λ tt [- 8; 8]

16 Model b quark coupling with the light neutral Higgs In the frame of the 2HDM-III, the coupling between the lightest Higgs and the b quarks is given by ( A(h 0 b b) = h 0 b sin α M diag ) cos α + sin α tan β D + ξ D b v 1 2

17 Outline Introduction Two Higgs Doublet Model type III (2HDM-III) Associated h 0 b b production Results Concluding Remarks References

18 Associated h 0 b b production Processes The processes involving b quarks and light Higgs bosons can be strongly enhanced in some 2HDM sceneries. These processes are: b h g b h g b b

19 Associated h 0 b b production Processes The processes involving b quarks and light Higgs bosons can be strongly enhanced in some 2HDM sceneries. These processes are: g q b h b q h g b b

20 Associated h 0 b b production The predominant mode is the qq, gg b bh 0 So the interesting events would have a total of four b jets in the final state. Two of these b jets should come from a Higgs resonance.

21 Associated h 0 b b production Associated hb b production Higgs boson production (in pb) at TEVATRON ( s = 2TeV)[1]

22 Associated h 0 b b production Associated h 0b b production The simulated cross section is compared with the experimental data, obtaining: 200 Sección eficaz vs. Masa del higgs ligero Sección Eficaz (pb) Resultados experimentales en D0 Lambda_bb = -4 Lambda_bb = -3 Lambda_bb = -2 Lambda_bb = 2 Lambda_bb = 3 Lambda_bb = Mh (GeV) Associated Higgs Boson Production( s = 2TeV)

23 Outline Introduction Two Higgs Doublet Model type III (2HDM-III) Associated h 0 b b production Results Concluding Remarks References

24 Results By using the bounds found before, we calculate de associated b/φ cross section: 8000 Sección eficaz vs. Masa del higgs ligero Sección Eficaz (pb) Mh (GeV) Associated Higgs Boson Production( s = 14TeV)

25 Outline Introduction Two Higgs Doublet Model type III (2HDM-III) Associated h 0 b b production Results Concluding Remarks References

26 Concluding Remarks The coupling between the light neutral Higgs and the fermions is quite sensitive to the existence of a non-minimal scalar sector. The actual colliders efficiency in effectivelly tagging b quarks allows us to reconstruct signals with many jets comming from b quarks.

27 Concluding Remarks By using the reported data comming from TEVATRON[3], we obtained bounds for the parameter λ bb. With the results, we calculated the associated b quark production of the light Higgs for the LHC.

28 Concluding Remarks The results can be corrected by making a full simulation for both, D0 and for TEVATRON. We can also compare other channels looking for new bounds.

29 Outline Introduction Two Higgs Doublet Model type III (2HDM-III) Associated h 0 b b production Results Concluding Remarks References

30 M. Carena, J. S. Conway, H. E. Haber, and J. D. Hobbs. Report of the higgs working group of the tevatron run 2 susy/higgs workshop, Rodolfo A. Diaz. Phenomenological analysis of the two higgs doublet model, Prolay Kumar Mal. Susy higgs searches at dø, tevatron R. Martinez, D. A. Milanes, and J. Alexis Rodriguez. The lightest higgs boson production at photon colliders in the 2hdm-iii. Physical Review D, 72:035017, Marc Sher. Scalar-mediated flavor-changing neutral currents, 1998.

31 Backup Talk Camilo Andrés Jiménez-Cruz J.-Alexis Rodríguez, Roberto Martinez Universidad Nacional de Colombia December 5, 2007

32 Outline Bounds over λbb Experimental Results Simulation Details Scalar sector of the 2HDM References

33 Outline Bounds over λbb Experimental Results Simulation Details Scalar sector of the 2HDM References

34 Bounds over λbb These bounds are obtainded in [6] from perturbation theory considerations over the tbh + coupling. They get the following restriction in the case of tan β = 1 m 2 b m 2 t λ bb 2 + λ tt 2 < 8 (m b = 4.2 ± 0.07GeV, m t = ± 3.3GeV[1])

35 Outline Bounds over λbb Experimental Results Simulation Details Scalar sector of the 2HDM References

36 Experimental Results D0 reported experimental searches of a light Higgs boson at s = 1.96TeV. One of those searches was in the associated φb b production with φ b b[5].

37 Experimental Results They used data collected by the D0 detector from November 2002 to June 2004, corresponding to an integrated luminosity of about 260pb 1. They searched for an excess in the invariant mass distribution of the two leading transverse momentum p T jets in events containing three or more b quark candidates.

38 Experimental Results

39 Outline Bounds over λbb Experimental Results Simulation Details Scalar sector of the 2HDM References

40 Simulation Details The simulations were made with CalcHEP[4]

41 Simulation Details The major source of background expected is SM s multijet production. We expect two main categories of multijet background. Genuine heavy-flavor jets Mistakenly tagged b-quark jets. (Light quarks or gluon branching)

42 Simulation Details All other backgrounds are expected to be small[2]: Channel pp Zb pp tt Expected σ pb pb

43 Simulation Details No SUSY background is assumed.

44 Outline Bounds over λbb Experimental Results Simulation Details Scalar sector of the 2HDM References

45 Scalar sector of the 2HDM The scalar sector is composed by two scalar doublets parameterized as[3]: Φ i = 1 2 ( 2φ + i h i + v i + iξ i )

46 Scalar sector of the 2HDM The most general scalar potential is much more complex than the SM s one: V g (Φ 1, Φ 2 ) = µ 2 1Â µ2 ˆB 2 µ 2 3Ĉ µ2 ˆD 4 + λ 1 Â 2 + λ 2 ˆB 2 + λ 3 Ĉ 2 + λ 4 ˆD 2 with + λ 5 Â ˆB + λ 6 ÂĈ + λ 7 Â ˆD + λ 8 ˆBĈ + λ 9 ˆB ˆD + λ 10 Ĉ ˆD Â Φ 1 Φ 1, ˆB Φ 2 Φ 2, Ĉ = Re ( Φ 1 Φ 2), ˆD = Im ( Φ 1 Φ ) 2

47 Scalar sector of the 2HDM The most general scalar potential is much more complex than the SM s one: V g (Φ 1, Φ 2 ) = µ 2 1Â µ2 ˆB 2 µ 2 3Ĉ µ2 ˆD 4 + λ 1 Â 2 + λ 2 ˆB 2 + λ 3 Ĉ 2 + λ 4 ˆD 2 with Assuming C invariance + λ 5 Â ˆB + λ 6 ÂĈ + λ 7 Â ˆD + λ 8 ˆBĈ + λ 9 ˆB ˆD + λ 10 Ĉ ˆD Â Φ 1 Φ 1, ˆB Φ 2 Φ 2, Ĉ = Re ( Φ 1 Φ 1), ˆD = Im ( Φ 1 Φ ) 1

48 Scalar sector of the 2HDM They are rotated: ( cos β sin β sin β cos β ) ( φ + 1 φ + 2 ( cos β sin β ) ( ξ1 sin β cos β ξ 2 ( cos α sin α ) ( h1 sin α cos α h 2 ) ( ) G ± = H ± ) ( ) G 0 = ) = A 0 ( H0 h 0 )

49 Scalar sector of the 2HDM The fermions masses are obtained by the introduction of the Yukawa s Lagrangian: L Y = η U,0 ij + ξ U,0 ij Q 0 il Φ 1 U 0 jr + η D,0 ij Q 0 il Φ 2 U 0 jr + ξ D,0 ij Q 0 il Φ 1 D 0 jr Q 0 il Φ 2 D 0 jr + l.s + h.c (1)

50 Scalar sector of the 2HDM The fermions masses are obtained by the introduction of the Yukawa s Lagrangian: L Y = η U,0 ij + ξ U,0 ij Q 0 il Φ 1 U 0 jr + η D,0 ij Q 0 il Φ 2 U 0 jr + ξ D,0 ij Φ 2 Φ 2 Q 0 il Φ 1 D 0 jr Q 0 il Φ 2 D 0 jr + l.s + h.c (1) D jr D jr and U jr U jr, Φ 1 decouples from fermions and Φ 2 gives mass to both sectors.

51 Scalar sector of the 2HDM The fermions masses are obtained by the introduction of the Yukawa s Lagrangian: L Y = η U,0 ij + ξ U,0 ij Q 0 il Φ 1 U 0 jr + η D,0 ij Q 0 il Φ 2 U 0 jr + ξ D,0 ij Φ 2 Φ 2 Q 0 il Φ 1 D 0 jr Q 0 il Φ 2 D 0 jr + l.s + h.c (1) D jr D jr and U jr U jr, η U,0 ij and ξ D,0 ij dissapear, Φ 1 couples to up sector while Φ 2 couples to down sector.

52 Scalar sector of the 2HDM The fermions masses are obtained by the introduction of the Yukawa s Lagrangian: L Y = η U,0 ij + ξ U,0 ij Q 0 il Φ 1 U 0 jr + η D,0 ij Q 0 il Φ 2 U 0 jr + ξ D,0 ij Q 0 il Φ 1 D 0 jr Q 0 il Φ 2 D 0 jr + l.s + h.c (1) No discrete symmetry

53 Scalar sector of the 2HDM By using the CSY anzats and tan β = 1, the couplings of the lightest Higgs are: A(h 0 f i f j ) = sin α v m iδ ij + cos α m i m j λ ij, 2v

54 Outline Bounds over λbb Experimental Results Simulation Details Scalar sector of the 2HDM References

55 Review of particle physics. ATLAS Collaboration. Atlas detector and physics performance, technical design report. Technical report, CERN, Rodolfo A. Diaz. Phenomenological analysis of the two higgs doublet model, Alexander Pukhov et al. Calchep. arxiv:hep-ph/ , Prolay Kumar Mal. Susy higgs searches at dø, tevatron R. Martinez, J. Alexis Rodriguez, and M. Rozo. Bounds on charged higgs boson in the 2hdm type iii from tevatron.