Update on the MSSM Interpretation of ATLAS Higgs Searches

1. Update on the MSSM Interpretation of ATLAS Higgs Searches Markus Schumacher , Bonn University On behalf of the ATLAS Collaboration Physics at LHC, LHC-Praha 2003, July 2003 • Higgs Sector and 4 Benchmark Scenarios • Observation potential for: h, A, H, H+- • Conclusions

2. The Higgs Sector of the MSSM • 5 physical Higgs bosons: h, H, A, H+, H- • on Born level:2 parameters tanb, mA mass limit mh < MZ • large loop corrections  mh < 133 GeV (+-3GeV) corrections depend on 5 SUSY parameters: Xt,M0,M2,Mgluino, m • 5 parameters fixed in4 benchmark scenariosconsidered • scan performed over tanb, mA Couplings MSSM/SM high tanb  large BR(h,A,H bb,tt) small a  small BR(hbb,tt) Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

3. The Four Benchmark Scenarios • (suggested by M.Carena et al. (hep/ph0202167), same as final LEP paper) • Influence mainly phenomenology of light Higgs boson h • MHMAX scenario(MSUSY=1 TeV ) maximal theoretically allowed region for mh • Nomixing scenario (now MSUSY= 2 TeV, 1TeV almost excluded by LEP ) • small mh difficult for LHC • Gluophobic scenario(MSUSY=350GeV) • coupling to gluons suppressed (cancellation of top + stop loops) • small rate for gluon gluon  H, Hggand Z4 leptons • Small a scenario(MSUSY = 800 GeV) coupling to b (and t) suppressed (cancellation of sbottom, gluino loops) for large tanb and MA 100 to 500 GeV Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

4. Mass of the light Higgs boson h 130GeV<Mh 120<Mh<130GeV 110<Mh<120GeV 100<Mh<110GeV 90<Mh<100GeV Mh<90GeV Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

5. Some Technicalities • All SM-like cross sections: leading order, no K-factors (K=1) • bottom and top pole masses used for tth, bbh and gbtH+,- • programs: HQQ,HIGLU, … (M.Spira) and xsec for gbtH+,-(T.Plehn) • Higgs masses, alpha_eff.: Feynhiggs 1.3(S.Heinemeyer et al.) • Branching ratios: HDECAY 3.0 (M.Spira et el.) (catch up with level of sophistication used at LEP) • decay in SUSY particles switched off for now • discovery = CLB(poisson) < 2.85x10-7 combination with likelihood ratio method (K. Cranmer, F.Cerutti) Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

6. Light CP Even Higgs Boson h New ! Vector Boson Fusion Channels : qqqqWWqqh q q with hWW, tt, (gg) (low luminosity only) h q q ggttH ggH bbh(hmm) g g t g b h h h g g t g b Hgg,ZZ4l (gg incl. analysis) hbb,(WW) See M. Vos‘ talk Questions: observation after which int. luminosity? which and how many channels ? Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

7. Light Higgs boson h: 30 fb -1 bbhmm VBF, htt VBF,htt+WW tthbb Excluded by LEP WWhlnbb VBF,hWW combined VBF channels cover large part of MSSM plane Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

8. Light Higgs boson h: 10 fb -1 Almost no individual channel observable  need combination of all channels 5s discovery 3s observation Excluded by LEP 5s discovery 3s observation Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

9. Light Higgs boson h: 300 fb-1 For high lumi.: A: hgg B: tthbb C: hZZ4lcontribute Excluded by LEP All three A and B A and C only B Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

10. h: Number of observable final states 300 fb-1 1 channel 2 channels 3 channels 4 channels Excluded by LEP 5 channels several channels observable allows parameter determination ? Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

11. SM or MSSM ? • Direct observation of additional Higgs bosons • Discrimination via couplings of light boson h • Direct search in the following channels: • Heavy Neutral Higgs bosons: channels for light h +H/A mm, tt (lep.+had., had.+had., low lumi only) H/Att, Hhhbbgg, AZHZhhbbll, WHWWW3l3n, HWWlnln • Charged Higgs bosons: gbtH+- with H+-tb and one tbln ttbWbH+-blnbtnH+-tn and t->bqqttbW bH+-bqq btn • (new channelssince TDR, channel with extended mass range) • Marginal differences between 4 benchmark scenarios  only MHMAX scenario is shown and discussed Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

12. Heavy Neutral Bosons: H/A VBF: Htt,WW H/Att H/Attlept.had. 30 fb-1 H/Attlept.had. +lept.lept. comb. H/Amm ttH with Hbb,WW H/Agg, HZZ4l, WHlnbb, Hhhbbgg, AZHZhhbbll, WHWWW3l3n, HWWlnln Excluded by LEP Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

13. Charged Higgs Bosons Two mass regions: i) MH < 170GeV (low lumi) 300 fb-1 30 fb-1 t b g top pairs tH+- b H g t Excluded by LEP gbtH+- H+tb,tbln ii) MH > 180GeV gbtH+- gbtH+- H+-tn, tbqq 10 fb-1 g t ttbWbH+-blnbtn b H ttbWbH+-bqqbtn Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

14. How many can be seen: h,H,A,H+- ? MHMAX scenario 300 fb-1 1 boson h,H,A,H+- 2 bosons 3 bosons All 4 bosons h,H,A h only No holes ! Complete plane covered h,H,A Excluded by LEP (also in other 3 benchmark scenarios) Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

15. Only h seen: is it the SM or the MSSM ? MHMAX scenario, 300fb-1 First preliminary look > 1 Higgs boson From VBF (30 fb-1) BR(htt) BR(hWW) R = only h 2 D=(RMSSM-RSM)/sexp D>1 • > 2 Excluded by LEP >1 Higgs boson 5s 3s 2s Only statistical error Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003

16. Conclusion • Updated interpretation of Higgs searches in 4 benchmark scenarios have been performed • Good coverage of MA-tanb plane for all 4 scen., due to complementarity of search channels • New channels for h,H,A,H+- increase sensitivity • Multiple channels observable for light Higgs h hope for discrimination between SM and MSSM Thanks for discussion and providing info and programs to • M. Spira (HDECAY,HIGLU,…), S. Heinemeyer (FeynHiggs) • T. Plehn (xsec for gbtH+-), K.Cranmer (statistics code) • especially Elzbieta R.W. +many others from the ATLAS Higgs group Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 2003