1.  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 Investigation of the Disovery Potential for Higgs Bosons of the MSSM with ATLAS Markus Schumacher, Bonn University June 2004, SUSY04, Tsukuba

2. 2 M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04, Tsukuba The Higgs sector of the CPC MSSM t b/ W/Z h cos sin -sin cos sin() H sin sin cos/ cos cos() A cottan ----- Couplings MSSM/SM  Two Higgs Doublets  5 physical bosons: h, H, A, H +, H -  at Born level 2 parameters: tan, m A m h < M Z  large loop corrections  m h < 133 GeV (+-3GeV) corrections depend on 5 SUSY parameters: X t,M 0,M 2, M gluino,   5 parameters fixed in the benchmark scenarios considered LO-SM-like cross sections Xsec for gb  tH +- from Plehn Program  small   small BR(h  ,bb)  large   large BR(h,H,A  ,bb)

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

4. 4 M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04, Tsukuba Experimental Issues  key performance numbers obtained from full simulation: e.g. b-tagging, -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

5. 5 M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04, Tsukuba Experimental Inputs channellumiMass rangePublication VBF, H  WW lowM>110 GeV SN-ATLAS-2003-024 ttH, H  bblow+highM>70GeV ATL-PHYS-2003-003 bbH/A   low+high70<M<135GeV M> 120 GeV ATL-PHYS-2002-021 ATL-PHYS-2000-005 bbH/A    lep.had   had. Had low M>120GeV M > 450 GeV ATL-PHYS-2000-001 ATL-PHYS-2003-008 ATL-PHYS-2003-008 gb  tH+-, H  ,tb low+highM >180 GeV SN-ATLAS-2002-017 tt  bW bH+-, H+-   lowM < 170 GeV ATL-PHYS-2003-58 H/A   low+highM > 350 GeV TDR A  Zh  llbb, H  hh  bb low+high60 <ML<130 100<MH<360TDR H   low+highM > 70 GeV TDR ZZ  4llow+highM > 100 GeVTDR WW  ll low+high140<M <120GEV TDR WH  lbb low70<M<130GeV TDR

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

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

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

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

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

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

12. 12 M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04, Tsukuba Overall Discovery Potential: 300 fb -1  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? ATLAS preliminary

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

14. 14 M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04, Tsukuba The CPX scenario  MSSM Higgs Sector CP conserving at Born level  CP effects via complex couplings in loops: Complex MSSM trilinear couplings A t, A b gluino mass M gluino M SUSY = 500 GeV, A t =A b =M gluino =1 TeV, =2TeV, M 2 =200GeV Maximal effect in Higgs sector  CPX scenario (suggested by Carena, Ellis, Pilaftsis, Wagner, Phys.Lett B495 155(2000)) maximal phase arg(A t )=arg(A b )=arg(M gluino )=90 degree large ratio A t /m susy scan of Born level parameter: tan and M H+-

15. 15 M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04, Tsukuba Phenomenology in the CPX scenario  all H 1, H 2 and H 3 couple to W and Z sum rule:  i g i (ZZH i ) = g SM (ZZH)  both H 2 and H 3 may decay to H 1 H 1, ZH 1, WW, ZZ  mass eigenstates H 1, H 2, H 3 not equal CP eigenstates h,A,H  low mass for H 1 (<50 GeV) not excluded by OPAL(LEP) H3 H2 H1

16. 16 M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04, Tsukuba Light Higgs Boson H 1  border of discovery region at low tanb mostly determined by availability of inputs (VBF >110 GeV, ttH and > 70 GeV)  border at low M H+- due to decoupling of H 1 from W,Z and t 30 fb -1 300 fb -1 ATLAS preliminary  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

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

18. 18 M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04, Tsukuba Overall Discovery Potential Zoom covered by taking into account signal overlap from H1 and H2 M H1 : < 70 GeV M H2 : 105 to 120 GeV M H3 : 140 to 180 GeV small masses not studied yet in ATLAS tiny „hole“ at border of VBF: H 1   H 2   discovery region ATLAS preliminary only H 1

19. 19 M. Schumacher, ATLAS Higgs Interpretation in the MSSM, SUSY04, Tsukuba Conclusions  Interpretation of ATLAS Higgs searches in 4 CPC benchmark and the CPX scenario have been performed  CPC scenarios: whole tan vs. M A plane covered, “wedge region“: only h observable maybe discrimination between SM and beyond by rate measurements  CPX scenario: uncovered region for now at low M H1 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, …