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Investigation of the Disovery Potential for Higgs Bosons of the MSSM with ATLAS

Investigation of the Disovery Potential for Higgs Bosons of the MSSM with ATLAS. Markus Schumacher , Bonn University June 2004, SUSY04, Tsukuba. CP Conserving (CPC) Benchmark Scenarios Discovery Potential in CPC scenarios Discrimination SM or Beyond

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Investigation of the Disovery Potential for Higgs Bosons of the MSSM with ATLAS

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  1. Investigation of the Disovery Potential for Higgs Bosons of the MSSM with ATLAS Markus Schumacher , Bonn University June 2004, SUSY04, Tsukuba • CP Conserving (CPC) Benchmark Scenarios • Discovery Potential in CPC scenarios • Discrimination SM or Beyond • The CP Violating CPX Scenario • Discovery Potential in the CPX Scenario • Conclusions

  2. The Higgs sector of the CPC MSSM • Two Higgs Doublets  5 physical bosons: h, H, A, H+, H- • at Born level 2 parameters: tanb, m A mh < MZ • large loop corrections  mh < 133 GeV (+-3GeV) corrections depend on 5 SUSY parameters: Xt,M0,M2,Mgluino, m • 5 parameters fixed inthe benchmark scenariosconsidered Couplings MSSM/SM LO-SM-like cross sections • small a  small BR(htt,bb) • large b  large BR(h,H,Att,bb) Xsec for gbtH+- from Plehn Program M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  3. The 4 CPC Benchmark scenarios Suggested by Carena et al. , Eur.Phys.J.C26,601(2003) • MHMAX scenario( MSUSY = 1 TeV ) maximal mh < 133 GeV • Nomixing scenario ( MSUSY = 1 TeV ) small mh < 116 GeV • Gluophobic scenario • suppressedcoupling to gluon • (cancellation of top+stop loops) small rate for : gg H, e.g. Hgg • MSUSY=350GeV, mh < 119 GeV • Small a scenario • coupling to b (t) suppressed • (canc. sbottom, gluinoloops) • for large tanb, MA 150500 GeV • MSUSY = 800 GeV, mh < 123 GeV Masses, coupling and BRs calculated with FeynHiggs (Heinemeyer et al.,Status Mai 04) M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  4. Experimental Issues • key performance numbers obtained from full simulation: e.g. b-tagging, t-id, mass resolutions .… • efficiencies and background expectations from fast simulations (some key analysis fully checked with full sim.) • int. lumi = 30 fb-1 ~ 2 to3 years at low lumi operation • int. lumi = 300fb-1 = 30 fb-1 @ low lumi. + 270fb-1 @ high lumi • corrections due to larger total decay width taken into account • signal overlap/ mass degeneracy of Higgs bosons considered • discovery = 5 sigma excess using Poissonian statistics combination of channels with likehood ratio method • no systematic uncertainties considered when evaluating observation potential M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  5. Experimental Inputs M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  6. Vector Boson Fusion: 30 fb-1 VBF:qqqqH studied for MH>110GeV at low lumi running ATLAS preliminary almost gurantees discovery of at least one h or H with 30 fb-1 SM like h with 30 fb-1 ttll4 n Following work by Plehn, Rainwater, Zeppenfeld M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  7. Light Higgs Boson h: 30 fb-1 ATLAS preliminary • difference in covered regions and contributing channels mainly due to difference in mh at same (tanb,MA) point M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  8. Small a scenario, h: 30 fb-1 hole due to suppressed branching ratio for H to tt ATLAS preliminary nicely covered by enhanced branching ratio to gauge bosons M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  9. Light Higgs Boson h: 300 fb-1 ATLAS preliminary • large area covered by several channels • stable discovery • allows parameter determination • small uncovered region at low mh = 90 to 100 GeV • hgg still sensitive in gluophobic scenario due to associated production Wh, tth M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  10. Heavy Neutral Higgs Bosons ATLAS preliminary large tanb region covered by ppbbH/A, H/Att,mm Rate for bbA, Att ~ (tanb)4 tthad.had 30fb-1. • coverage similar in 3 other scenarios • running bottom quark mass used M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  11. Charged Higgs Bosons ATLAS preliminary high mass: mH+-> mtop gbH+-t H+-tn tbqq low mass: mH+-< mtop ggtt ttH+-bWb 30fb-1 WqqH+-tn • transition region around mtop needs revised experimental analysis • running bottom quark mass used M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  12. Overall Discovery Potential: 300 fb-1 ATLAS preliminary • whole plane covered in all four CP conserving benchmark scenarios • significant area where only h is observable • Can we distinguish between SM and extended Higgs sectors by parameter measurements? M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  13. SM or Extended Higgs Sectors? ATLAS preliminary first look using rate measurements from VBF channels (30fb-1) BR(htt) BR(hWW) R = Deviation from SM expectation D=|RMSSM-RSM|/sexp potential for discrimination seems promising! • only statistical errors considered • assume Higgs mass exactly known M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  14. The CPX scenario • MSSM Higgs Sector CP conserving at Born level • CP effects via complex couplings in loops: Complex MSSM trilinear couplings At, Ab gluino mass Mgluino Maximal effect in Higgs sector  CPX scenario (suggested by Carena, Ellis, Pilaftsis, Wagner, Phys.Lett B495 155(2000)) maximal phase arg(At)=arg(Ab)=arg(Mgluino)=90 degree large ratio mAt/msusy scan of Born level parameter: tanb and MH+- MSUSY = 500 GeV, At=Ab=Mgluino=1 TeV, m=2TeV, M2=200GeV M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  15. Phenomenology in the CPX scenario • mass eigenstates H1, H2, H3 not equal CP eigenstates h,A,H • all H1, H2 and H3 couple to W and Z sum rule: Sigi (ZZHi) = gSM (ZZH) • both H2 and H3 may decay to H1H1, ZH1,WW, ZZ H1 H2 H3 • low mass for H1 (<50 GeV) not • excluded by OPAL(LEP) M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  16. Light Higgs Boson H1 ATLAS preliminary 30 fb-1 300 fb-1 • border of discovery region at low tanb mostly determined by availability of inputs (VBF >110 GeV, ttH and gg > 70 GeV) • border at low MH+- due to decoupling of H1 from W,Z and t • for VBF channels: assume same efficiencies for contribution of CP even and CP odd states (needs to be checked) • for ttH: efficiencies for CP even and odd bosons are the same M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  17. Heavy Neutral and Charged Higgs Bosons Heavy Neutral Bosons Charged Bosons ATLAS preliminary • coverage similar to CPC scenarios • more complex in low tanb region due to larger number of decay channels for H2 and H3 M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  18. Overall Discovery Potential ATLAS preliminary Zoom only H1 tiny „hole“ at border of VBF: H1ttH2tt discovery region only H1 covered by taking into account signal overlap from H1 and H2 MH1: < 70 GeV MH2: 105 to 120 GeV MH3: 140 to 180 GeV small masses not studied yet in ATLAS M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

  19. Conclusions • Interpretation of ATLAS Higgs searches in 4 CPC benchmark and the CPX scenario have been performed • CPC scenarios: whole tanb vs. MAplane covered, “wedge region“: only h observable maybe discrimination between SM and beyond by rate measurements • CPX scenario: uncovered region for now at low MH1 because small masses not investigated in ATLAS yet results need cross check with CPSUPERH(Lee, Pilafstis et al.) study different values for complex phases Thanks for programs and discussions to: Philip Bechtle, Sven Heinemeyer, Tilman Plehn David Rainwater, Michael Spira, ATLAS Higgs working group, … M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04 , Tsukuba

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