Satyaki Bhattacharya

1. Higgs Search with the CMS detector at LHC Satyaki Bhattacharya S. Bhattacharya

2. data taking starts 2007 Startup Luminosity 2X1033 cm-2/s that is: 20 fb-1 per year Silicon Tracker PbWO4 ECAL sampling brass HCAL solenoid 4Tesla field MUON Chambers numbers are for barrel S. Bhattacharya

3. Standard Model Higgs S. Bhattacharya

4. Higgs production at LHC ggH High gluon flux – dominant although loop process Vector Boson Fusion (VBF) 10% at MH=100GeV Comparable to gg->H at MH=1 TeV ttH, bbH,HW,HZ S. Bhattacharya

5. Decays and Search Strategy MH < ~140 GeV Hbbdominant ggHbb : background too large ttHttbb possible Hgg –small BR but very clean MH < ~500 GeV 120-200 GeV HWW*/WWlnln (serious tt,Wtb background) 200-500 GeV HZZ4l gives highest sensitivity between 200-500 GeV MH > ~500 GeV GH large, use channels with large BR, HZZ/WW VBF x-sec large and can be used search channels S. Bhattacharya

6. Low mass(<140 GeV): H gg Two clean electromagnetic clusters For unconverted photons Backgrounds: gg,qqgg,qgqg sgg=646MeV 5s discovery in ~15 fb-1 events/50MeV mgg for 130 GeV Higgs S. Bhattacharya

7. H  ZZ  4 Clean, resolution better than 1GeV Discovery Luminosity: S. Bhattacharya

8. Discovery reach of CMS • CMS can probe the entire “allowed” mass range • 5s discovery possible in few months in many channels Total HZZl+l-l+l- HWWllnn Hgg S. Bhattacharya

9. Higgs in MSSM S. Bhattacharya

10. MSSM Higgs sector Two Higgs doublets pseudoscalar Higgs 3 fields are gauged away 8 real Higgs fields ( 4 complex fields) charged Higgs heavy Higgs light Higgs All masses, x-sections,BRs and mixing angle a are determined by two parameters tanb– ratio of vacuum expectation values of the two doublets MA– mass of pseudoscalar Higgs A S. Bhattacharya

11. h discovery @ 30fb-1 Decay BRs and searches for h are like SM Higgs S. Bhattacharya

12. H±discovery @ 30 fb-1 For charged higgs associated production with top is dominant S. Bhattacharya

13. A/H discovery @ 30 fb-1 At large tanb A/H coupling to down type fermion is strong and H production with bb and H decay to t become important S. Bhattacharya

14. A/H t+t- jets + X Higgs signal over total background Signal: gg  bbH/A and ggH/A H/A  t+t - MA 500GeV s.Br=0.188pb MA 200GeV s.Br=9.53pb full simulation + NLO x-section backgrounds: Z/g*2t, multijets faking t tt and W+jet with Wtn reduce background by requiring: narrow t jet, b-tag,central jet veto. t impact parameter,vertexing ~15% mass resolution S. Bhattacharya

15. Summary • CMS is capable of searching SM Higgs over the entire allowed mass range between LEP MH limit and ~ TeV (unitarity bound) • Atleast one MSSM Higgs will be found in entire MA-tanb plane • 5s discovery possible in few months • Few hundred MeV mass resolution from Hgg, HZZ4l for low-intermediate mass Higgs • Also • CP and spin of Higgs can be measured with 100fb-1 S. Bhattacharya

16. Extras S. Bhattacharya

17. Interm. Mass: H  WW  ll'X Isolated leptons + ETmiss tt serious background  Require central jet veto S. Bhattacharya

18. High Mass: ZZ lljj HZZ lljj has large branching fraction at higher masses. Mass reconstruction possible but GH is large S. Bhattacharya

19. ttH, H bb Preselection: 1 isolated lepton + atleast 6 jets Likelihood based analysis: L_event = Anti b-tag prob. of W jets X b-tag prob of other jets X Mass prob. of W,t,t X sorting of b-jet energies Pick jet combinations with highest L_event. Select event based on 3 likelihood functions, then count Events around mass window. Efficiencies: 115 GeV H = 1.3% ttbb = 0.4%, ttZ = 0.2% (full dettector simulation done) Reconstructed masses of H,W,t,t S. Bhattacharya

20. VBF : New channel H decay H decay Features: Forward tagged jets Relatively high pT Higgs Important at very high mass (10% at low mass, total at very high mass) Very useful for WW*, also used for gg,t+t- at lower mass S. Bhattacharya

21. MSSM Higgs Production ggH most important at low mass and low tanb light higgs production x-sections similar to SM higgs at high tanb gg/qqHbb dominant for heavy Higgs for H± tttH-b is most important S. Bhattacharya

22. MSSM Higgs Production (ii) S. Bhattacharya

23. Higgs Production in MSSM(details) • H/A production • ggH/A, gg/qqbbH/A • g(AVV)=0  no VBF • At large tanβ • VBF suppressed for H • g(A/Hbb) enhanced  ~90% bbH/A for tanβ>10 and MA>300 GeV • H SM-like near lower mass limit ( high tanβ, small MA)VBF significant • h production • h SM-like for MA>mhmax Higgs couplings with up(u) down(d) fermions and vector bosons (v) • H± production For MH±<Mt :tttH±b For MH±>Mt: • ggtbH±,H+H-,W±H± • gbtH± • qqH± S. Bhattacharya

24. channels considered for a SUSY Higgs • H/h gg, bb • H->bb in WH,ttH • h->gg in Wh, tth->lgg • H/hZZ*/ZZ4l • h/H/At+t-  (e/m)jET, emET,jjET • Including qqH,ttH,WH • H+t+n from tt • H+t+n, H+tb for MH+>Mt • AZh with hbb • Agg • H/A c02c02, c0ic0j, c+1c-2 • H±c+2c02 ~ ~ ~ ~ ~ ~ ~ ~ S. Bhattacharya

25. A/H t+t- jets + X (detailed efficiency) S. Bhattacharya

26. Httleptons Signal: ggH or ggbbH, H t t, t  leptons s.Br is ~ 100 – 900 fb at high tanb bbH strongly dominant. Background: leptonic final states of Z/g*,tt,bb,WW,WZ require isolated leptons, pt>20GeV (isolated=no tracks with pt> 2GeV in DR=0.3) eliminates bb background ct of t ~90mm. Use impact parameter of leptons to identify t reduces Z/g*,tt backgrounds require 1 jet with pt>20 GeV and b-tag kills Drell Yan This channel should be useful even if sparticles are light S. Bhattacharya

27. H/A  m+m- • ppbbH/A + X with H/A  m+m- 2soft(ET< 50GeV) b jets • Use b-tag against Z/g* background • Use central jet veto against tt Mass resolution 1%, |mH-mA| ~ 2 GeVH/A peaks superimposed (mass difference can be upto ~ 5.5 GeV) S. Bhattacharya

28. MSSM Discovery reach Ref: Paris Sphicas, Physics at LHC,Vienna,2004 S. Bhattacharya

29. MSSM discovery reach (ii) S. Bhattacharya

30. CMS Trigger Rates CMS total level1 rate is 16 kHz at startup Total High Level Trigger (HLT) is 100 Hz. S. Bhattacharya