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Prospects of Charged Higgs Boson Discovery @ Colliders

Prospects of Charged Higgs Boson Discovery @ Colliders. D. P. Roy Homi Bhabha Centre for Science Education Tata Institute of Fundamental Research Mumbai, India. Outline. Charged Higgs Boson in the MSSM H  Lighter than top(t): t  bH + H  Heavier than top : gbtH - (NLO Cont.)

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Prospects of Charged Higgs Boson Discovery @ Colliders

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  1. Prospects of Charged Higgs Boson Discovery @ Colliders D. P. Roy Homi Bhabha Centre for Science Education Tata Institute of Fundamental Research Mumbai, India

  2. Outline • Charged Higgs Boson in the MSSM • H Lighter than top(t): t  bH+ • H Heavier than top : gbtH- (NLO Cont.) • H± beyond the MSSM : NMSSM & CPVMSSM • SUSY QCD Correction to H± signature

  3. 8 States - 3 Goldstone = 5 Physical St : h0, H0, A0& H± H± carries unambiguous hallmark of MSSM Higgs sector All the MSSM Higgs masses & couplings => MA & tan β

  4. mt > MH± => large tbH+ BR at tan β  1 & tan β  mt/mb LL QCD Corr => mq mq(MH±) => mt =170, mb = 3, mc =1 GeV Pert. Lim. of H±tb coupling => tan β > 1/3 & tan β < 3mt/mb 170 H± decay: tan β < 1 & tan β > 1 (MH± < 140 GeV) H±  cs H±  τν => Deficit in t  bW blν (MH± > 140 GeV) H±  t*bWbb => t bH+ bbbW=> b tag excess Moretti & Stirling; Djouadi, Kalinowski & Zerwas; Ma, Roy & Wudka

  5. MH= 140 GeV tan β ~ 8 problematic Using τ Pol can help to enhance Hτν Sig over W Bg

  6. g t t b H¯ t g t H¯ b g b Production of Heavy H± ( MH > mt ) at LHC LO (Zhu; Plehn et al.) NLO QCD Correction => K  1.5 g t t g (a) t g + t g => 0.8 (0.6) b H¯ b H¯ (b) - overlapping cont. from LO => -0.3 (0) for μF = μR = MH + mt , ( μF = (MH + mt)/5)

  7. Main BRs of H± (MH>200) H± tb dominant at all tanβ Large QCD Bg Signals with 3 & 4 b-tags H± Wh(A) main subdominant at small tanβ ~ 3 (BR 5%) Marginal in MSSM (NMSSM & CPV-MSSM) H± τν main subdominant at large tanβ > 10 (BR~20%) Most promising Signal

  8. g g t t b g Heavy H± (MH>200GeV)Signal at LHC in hadronic τ decay channel Sig has much harder pTτ-jet > 100 GeV(Enhanced byτ pol effect). Azimuthal angle between τ-jet and missing-pT is peaked in backward direction for signal ( forward direction for background). Transverse mass of τ-jet and missing-pT —> MH for Sig (MW for Bg)

  9. τ-Polarization: H  τ (Pτ =+1) gives hard τ-jet from π,ρL, a1L W  τ (Pτ = -1) gives hard τ-jet from ρT , a1T Can be distinguished from X= pπ± / pτ-jet => 90% of 1-pr. hadronic decay V = ρ,a1

  10. Raychaudhuri & Roy Hardness of π± reqd for τ-id => X > 0.3 (low-X peaks of ρL , a1Linaccessible) X > 0.8 cut will retain the high-X ρL & π conts ( Pτ = + Signal), while effectively suppressing the ρT ,a1T conts ( Pτ = – bg ). It will also suppress the fake τ bg from QCD jets effectively.

  11. Guchait, Kinnunen & Roy hep-ph/0608324 PYTHIA+TAUOLA + CMSJET Hardness of π± reqd for τ-id => X > 0.3 X > 0.8 cut retains most of the remaining Signal, while effectively suppressing the Bg.

  12. 3-prong τ-jet without π0 R3 > 0.8 or < 0.4 retains most of the Signal, while suppressing the Bg.

  13. mT > 200 GeV cut effectively suppresses the Bg without affecting the Signal. Provides estimate of H± mass.

  14. H± discovery limit at LHC with luminosity of 30 fb -1 (solid) and 100 fb -1 (dashed lines).

  15. g t t b H¯ Detection of H±  tb Signal at LHC with 3 b-tags :Moretti & Roy 3 pT (b3) > 80 GeV BG large, but 5σ Sig possible at very large (small) tan β

  16. t g t H¯tb3 b g b4 H± tb Signal at LHC with 4 b-tags: Miller, Moretti, Roy& Stirling Eb3> 120 GeV Mbb> 120 GeV cos θbb < 0.75 pT (b4 )>20 GeV Better Sig/Bg at the cost of a smaller Sig size compared to the 3 b-tags

  17. Assamagan, Coadou & Deandrea can fill up intermediate tanβ region for some favorable SUSY parameters Datta, Djouadi, Guchait & Mambrini Viability of H±  tb channel is not supported by the full simulation study:Lowette, D’Hondt &Vanlaer

  18. Extensions of MSSM (NMSSM & CPV-MSSM) Low Tanβ ( < 5 ) region: A not observable at LEP MSSM: Mh > 110 GeV => MA > 160 GeV => MH±> 180 GeV NMSSM: Allows MA1 < 60 GeV with a large doublet component & MH± = 140 - 160 GeV => H± A1W Drees,Guchait & Roy

  19. CPV-MSSM: hA mixing => light H1 with large A comp, MH1< 60 GeV & MH±= 130-150 GeV => H± H1W± t  bH± bH1W bbbW Ghosh, Godbole & Roy

  20. t  bH± bH1W bbbW

  21. t H± b SUSY QCD Correction : Non-decoupling Hall et al., Carena et al., Coarasa et al., Bartl et al. Estimate of Δb at Snowmass points & slopes in mSUGRA, GMSB & AMSB => Δb 20% for tanβ 30 ( ΔKSM~ 20%)Plehn et al.

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