Probing super light neutral Higgs boson at the LHC in CP violating - PowerPoint PPT Presentation

Probing super light neutral Higgs boson at the LHC in CP violating MSSM Higgs sector Dilip Kumar Ghosh Department of Theoretical Physics Indian Association for the Cultivation of Science 2A & 2B Raja S.C. Mullick Road, Kolkata, India Tohoku University,Sendai, Japan 1-2 September, 2010

Plan • CP violating ( � CP) MSSM Higgs sector • General feature of the phenomenology of the CP violating ( � CP) MSSM Higgs sector • Study of ultra light Higgs boson ( m H ≤ 60 GeV) at LHC in Four possible scenarios • Summary Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh

CP violation in Higgs sector • CP violation arises naturally in the three generation SM (Phase in the CKM matrix) • The CP violation has been first measured in neutral K -meson decays. [J. H. Christenson, J. W. Cronin, V. L. Fitch, and R. Turlay , Phys. Rev. Lett. 13, 138 (1964)] • CP non-conservation provides a key ingredient for cosmological baryogenesis • It is possible to have CP violation in Multi-Higgs models • MSSM contains an extended Higgs sector : may realize CP violation Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh

General frame work • Higgs potential of the MSSM is invariant under CP at the tree level • Two CP-even neutral Higgs bosons : h 0 , H 0 ( M H 0 > M h 0 ) • One CP-odd neutral Higgs boson : A 0 • One charged Higgs boson : H ± • M A , tan β, µ and A t,b control the MSSM Higgs spectrum • The tree level CP invariance of the MSSM Higgs potential may be violated sizeably by loop effects involving soft CP-violating trilinear couplings A t,b [ A. Pilaftsis, PRD58,096010 (1998) and PLB435,88 (1998)] Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh

CP violation in MSSM • After radiative corrections to the tree level Higgs potential: CP violation induced through loop effects via 3 generation sfermion and gaugino mass parameters • From the one loop effective potential Higgs boson mass matrix is calculated [J.Ellis et al’90, Y.Okada et al ’90, E.Haber et al’90,..M.Carena et al’95...A.Demir’99, A.Pilaftsis et al’99... S.Y.Choi et al’99] ! M 2 M 2 M 2 S SP N = M 2 M 2 P S P • M 2 S , M 2 P and M 2 SP denote the 2 × 2 matrices of the scalar, pseudoscalar and scalar-pseudoscalar squared mass terms of the neutral Higgs bosons. � m 4 � � � 1 , | A t | 2 | µ | 2 | µ || A t | , | µ || A t | M 2 t P S ≃ O sin φ CP , 32 π 2 M 2 M 2 tan βM 2 M 2 v 2 S S S S • M S is stop mass average, φ CP = Arg ( A t,µ ) Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh

CP violation in MSSM Higgs sector • In CP conserving MSSM: M SP = 0 : 2 CP-even h, H and one CP-odd A. • Diag( M 2 H 1 , M 2 H 2 , M 2 H 3 ) = O T M 2 N O , with M H 1 < M H 2 < M H 3 • After diagonalization the Physical mass eigenstates are mixed states of CP, H 1 , 2 , 3 have undefined CP properties. • To get sizeable CP violation, large | µ | , | A t,b | and large sin φ CP are needed • m A no longer a physical parameter, but the m H ± can be used as a physical parameter • Elements of matrix O are similar to cos α and sin α in the CP-conserving case. But 3 rd row and column are zero in the non-diagonal elements in such a case • Large m H ± implies H 1 → H sm Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh

The interaction between Higgs and gauge bosons 3 � 1 µ W − ,µ + g H i V V [ H i W + H i Z µ Z µ ] L H i V V = gm W 2 c 2 W i =1 3 � g ↔ ∂ µ H j ) Z µ L H i H j Z = g H i H j Z ( H i 2 c W j>i =1 3 � g ↔ ∂ µ H − ) W + ,µ L HH ∓ W ± = g H i H − W + ( H i 2 c W i =1 g H i V V = O 1 i cos β + O 2 i sin β, g H i H j Z = O 3 i (cos βO 2 j − sin βO 1 j ) − ( i ↔ j ) g H i H + W − = O 2 i cos β − O 1 i sin β + iO 3 i g H k V V = ǫ ijk g H i H j Z • We have the following Sum rules: 3 g 2 X HiV V = 1 , i =1 Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh

Implications of CP violating phases on Higgs searches The CPX Scenario ( Carena, Ellis, Pilaftsis & Wagner, PLB495(2000) 155 ) • Designed to showcase the effects of CP violation in the MSSM Higgs sector M ˜ t = M ˜ b = M ˜ τ = M SUSY µ = 4 M SUSY , | A t,b,τ | = 2 M SUSY , | M ˜ g | = 1TeV • Allows the following parameters to vary: tan β, M H ± , M SUSY Φ A t , Φ A b , Φ A τ , Φ ˜ g , Φ µ • The spectrum is generated by CPSUPERH code [J. S. Lee etal, Comput.Phys.Commun. 156,283(2004), hep-ph/0307377] Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh

Implications of CP violating phases on Higgs searches 140 M H1 , M H2 [ GeV ] 130 120 110 100 90 • ( a ) M H 1 , M H 2 and ( b ) g 2 H i ZZ as functions of 80 CPX scenario Arg( A t ) , in the CPX scenario for M SUSY = 1 70 60 TeV and for the following choices of M SUSY = 0.5 TeV 50 ( M H ± , tan β ) : (160 GeV, 4)(solid lines), 40 0 20 40 60 80 100 120 (150 GeV, 5) (dashed lines) and (140 GeV, arg (A t ) = arg (A b ) [ deg ] (a) 6) (dotted lines) H3ZZ 1 , g 2 g 2 H2ZZ , g 2 H3ZZ H1ZZ g 2 g 2 -1 H3ZZ 10 g 2 H1ZZ g 2 H2ZZ -2 10 0 20 40 60 80 100 120 arg (A t ) = arg (A b ) [ deg ] (b) Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh

Implications of CP violating phases on Higgs searches • In CPC MSSM, we have access only two neutral Higgses h, H in Higgsstrahlung /WW fusion process • In CPV MSSM, the three neutral Higgs mass eigenstates H i (i=1,2,3) do not have well defined CP quantum numbers. • Each of them can be produced in the Higgs-Strahlung process: ( e + e − → ZH i ) and/or in the WW fusion ( e + e − → H i ν e ¯ ν e ) • Also in pair ( e + e − → H i H j ( i � = j )) • The relative rates depend of the choice of the parameters describing the CP-odd/even mising. [A.Akeroyd & A. Arhrib, PRD64,095018 (2001)] Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh

Higgs production in CP violating MSSM • We studied WH i and ZH i , ( i = 1 , 2 , 3) pair production at Tevatron ( p ¯ p ) Run II and LHC ( pp ) Collider. [Arhrib,Ghosh & Kong,PLB’2002] • Our parameters are fixed as: Set A: M Q = � � M t = � M b = 1TeV , | µ | = 4TeV , | A t | = | A b | = 2TeV , Arg( A t ) = Arg( A b ) , tan β = 6 Set B: M Q = � � M t = � M b = 0 . 5TeV , | µ | = 2TeV , | A t | = | A b | = 2TeV , Arg( A t ) = Arg( A b ) , tan β = 15 • Interested in M H ± < ∼ 300 GeV M H ± > 300 is the decoupling scenario and H 1 is SM like V V H 1 = 1 , V V H 2 = V V H 3 = 0 Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh

Higgs production in CP violating MSSM 150 200 H 3 H 3 Higgs Mass (GeV) 130 180 H 2 H 2 110 160 90 140 H 1 H 1 70 (d) 120 (a) 50 100 1 • Tevatron Run II energy. M H ± = 150 (left ZH 1 ZH 1 pannel) and 200 GeV (right pannel). Other 0.01 ZH 2 ZH 3 σ (pb) ZH 2 MSSM parameters correspond to set A . ZH 3 0.0001 (e) (b) 1e-06 1 WH 1 WH 2 WH 3 0.01 σ (pb) WH 2 WH 3 WH 1 0.0001 (f) (c) 1e-06 0 20 40 60 80 100 120 140 160 180 0 20 40 60 80 100 120 140 160 180 Φ CP (degree) Φ CP (degree) Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh

Higgs production in CP violating MSSM 150 200 H 3 H 3 Higgs Mass (GeV) 130 180 H 2 H 2 110 160 90 140 H 1 H 1 70 (d) 120 (a) 50 100 10 • LHC energy. M H ± = 150 (left pannel) and ZH 1 ZH 1 1 ZH 2 200 GeV (right pannel). Other MSSM ZH 3 ZH 2 0.01 σ (pb) ZH 3 parameters correspond to set A . 0.0001 (e) (b) 1e-06 10 WH 1 WH 1 1 WH 2 WH 3 WH 2 0.01 σ (pb) WH 3 0.0001 (c) (f) 1e-06 0 20 40 60 80 100 120 140 160 180 0 20 40 60 80 100 120 140 160 180 Φ CP (degree) Φ CP (degree) Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh

Higgs search in CP violating MSSM Higgs sector LEP(95)/TeV(3 σ )/LHC(5 σ ) for CPX 0.5 20 40 60 80 100 120 20 40 60 80 100 120 40 40 • M. Carena etal. [NPB659,145 (2003)] 30 30 looked for several channels for Higgs boson 20 20 H i searches at hadron colliders 10 10 • 45 ◦ line: Tevatron: W/ZH i ( → b ¯ b ) . 5 5 90 0 60 0 • 135 ◦ line: LHC: gg H i → → tan β 2 2 γγ ( 100 fb − 1 ) , 40 40 30 30 tH i ( → b ¯ b )( 100 fb − 1 ) , t ¯ 20 20 W W/ZZH i ( → τ + τ − )( 100 fb − 1 ) . 10 10 • dark grey → LEP exclusion. 5 5 • Gaps at M H 1 ≤ 50 GeV for 90 ◦ and 60 ◦ 30 0 0 0 2 2 20 40 60 80 100 120 20 40 60 80 100 120 M H1 (GeV) Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh

LEP-2 exclusion • Exclusions, at 95% CL(light-green) and the 99 . 7% CL(dark-green) (b) tan β • Two main channels LEP studied : ( a ) Excluded e + e − → H 1 Z ( H 2 Z ) and ( b ) e + e − → H 1 H 2 by LEP 10 10 • For low M H 1 , LEP looked at e + e − H 1 H 2 → H 1 ( H 1 H 1 ) → 6 b jets ,and 6 τ leptons 1 1 Theoretically CPX Inaccessible 0 20 40 60 80 100 120 140 2 ) m H1 (GeV/c [Eur.Phys.J.C47, 547 (2006)] Tohoku University, Sendai, Japan, 1-2 September, 2010 Dilip Kumar Ghosh