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. 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 Outline

3. 8 States - 3 Goldstone = 5 Physical St : h 0, H 0, A 0 & H ± H ± carries unambiguous hallmark of MSSM Higgs sector All the MSSM Higgs masses & couplings => M A & tan β

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

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

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

7. Main BRs of H ± (M H >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. Heavy H ± (M H >200GeV) Signal at LHC in hadronic τ decay channel g g t g b t Sig has much harder p T τ-jet > 100 GeV (Enhanced by τ pol effect). Azimuthal angle between τ-jet and missing-p T is peaked in backward direction for signal ( forward direction for background). Transverse mass of τ-jet and missing-p T —> M H for Sig (M W for Bg)

9. τ-Polarization: => 90% of 1-pr. hadronic decay V = ρ,a 1 H  τ (P τ =+1) gives hard τ-jet from π,ρ L, a 1L W  τ (P τ = -1) gives hard τ-jet from ρ T, a 1T Can be distinguished from X = p π± / p τ-jet

10. Raychaudhuri & Roy Hardness of π ± reqd for τ-id => X > 0.3 (low-X peaks of ρ L, a 1L inaccessible) X > 0.8 cut will retain the high-X ρ L & π conts ( P τ = + Signal), while effectively suppressing the ρ T,a 1T conts ( P τ = – bg ). It will also suppress the fake τ bg from QCD jets effectively.

11. Guchait, Kinnunen & Roy hep-ph/0608324 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. PYTHIA+TAUOLA + CMSJET

12. 3-prong τ-jet without π 0 R 3 > 0.8 or < 0.4 retains most of the Signal, while suppressing the Bg.

14. m T > 200 GeV cut effectively suppresses the Bg without affecting the Signal. Provides estimate of H ± mass.

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

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

17. H ±  tb Signal at LHC with 4 b-tags: Miller, Moretti, Roy& Stirling t H ¯  tb 3 b4b4 g g t b E b3 > 120 GeV M bb > 120 GeV cos θ bb < 0.75 p T (b 4 )>20 GeV Better Sig/Bg at the cost of a smaller Sig size compared to the 3 b-tags

18. 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

19. Extensions of MSSM (NMSSM & CPV-MSSM) Low Tanβ ( < 5 ) region: A not observable at LEP MSSM: M h > 110 GeV => M A > 160 GeV => M H± > 180 GeV NMSSM: Allows M A1 < 60 GeV with a large doublet component & M H± = 140 - 160 GeV => H ±  A 1 W Drees,Guchait & Roy

20. CPV-MSSM: hA mixing => light H 1 with large A comp, M H1 < 60 GeV & M H± = 130-150 GeV => H ±  H 1 W ± t  bH ±  bH 1 W  bbbW Ghosh, Godbole & Roy

21. t  bH ±  bH 1 W  bbbW

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