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MSSM Higgs Bosons decaying in SUSY cascade with ATLAS

MSSM Higgs Bosons decaying in SUSY cascade with ATLAS. Simonetta Gentile Università di Roma, La Sapienza, INFN on Behalf of ATLAS Collaboration. Outline. Motivation MSSM Higgs in SUSY cascade search limits at LHC Bench mark points Detection MSSM Higgs in ATLAS

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MSSM Higgs Bosons decaying in SUSY cascade with ATLAS

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  1. MSSM Higgs Bosons decaying in SUSY cascade with ATLAS Simonetta Gentile Università di Roma, La Sapienza, INFN on Behalf of ATLAS Collaboration Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  2. Outline • Motivation • MSSM Higgs in SUSY cascade search limits at LHC • Bench mark points • Detection MSSM Higgs in ATLAS • Analysis: first results on neutral & charged Higgs discovery potential • Conclusions • The results presented are preliminary. Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  3. SUSY & Higgs interplay If SUSY kinematically accessible, then real production of sparticles. • Higgs can decay directly to or come from decay of SUSY particles • Associated production modes: e.g, squark-squark-Higgs • SUSY particles suppress or enhance loop induced production or decays Higgs into sparticle decay modes can compete with SM modes: H/A →c02c02→ 4 ± X Pioneering papers: H± →c02c±1→ 3 ± X [1] ATLAS Coll., ATLAS detector and Physics Perfomance, Vol.2 p766 [2] F. Moortgat, S. Abdullin, D. Denegri”. hep-ph/0112046 [3] M.Bisset, F. Moortgat and S. Moretti “Eur.Phys.J.C30:419-434,2003. [4] C. Hansen, N. Gollub, K. Assamagan, T. EkelofEur.Phys.J.C44S2:1-9,2005. [5]CMS Coll., CMS detector and Physics Perfomance, Vol.1 Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  4. Signature • Assume a classical production Mechanism • Decays 4 isolated leptons (e,m)+ ETmiss powerful signature against the SM + SUSY backgrounds at LHC Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  5. A/H susy decays A,H →c02,3,4 c02,3,4→4 ±+ EmissT A,H →c+2 c-1,2 →4 ±+ EmissT =eμ s(pp →H/A) Br(A,H →4 ±+N) tanb = 20 MA=500GeV M2[GeV] c20c20 c3,40c3,40 m [GEV] M.Bisset,N.Kersting,F.Moortgat,S.Moretti,arXi:0709.10029[hep –ph] Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  6. Search in a LHC detector Point A M0=125 GeV tanb=20 Point B M0=400 GeV tanb=20 M½=165GeV sign(m)=+1 A0=0 • Representive points studied: • MSSM representative Points • MSugra representative Points • Discovery potential in a typical LCH detector investigatedwith this selections: • 4 leptons |h |< 2.4 ,ET > 7.4 GeV • lepton Isolation • 2pairs of opposite sign • |MZ ±10 GeV| veto • 20 GeV<ET < 80 GeV • ETjet < 50 GeV Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  7. Reach for MSSM Higgs bosons inc02,3,4c02,3,4or c1,2+c2- pairs M.Bisset,N.Kersting,F.Moortgat,S.Moretti,arXi:0709.10029[hep –ph] Point 2 MA=600 GeV tanb=35 M1=100GeV M2=200 GeV m=-200GeV Ml=150GeVMt= 250GeV mg=800GeV Mq=1000GeV Point 1 MA=500 GeV tanb=20 M1=90GeV M2=180 GeV m=-500GeV Ml=Mt= 250GeV mg=Mq=1000GeV Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  8. Choice of Bench mark points To choose representative points in the search A/H→ci0ci0→ 4 The following characteristics • mtop= 175 GeV • mb= 4.25 GeV • tan β= 10 • mA= 500 GeV • Msquark= 1 TeV • Atau= 0 • Aℓ= 0 • mℓ=mτsoft= 250 GeV • “High” branching ratio in • c02c02 • c02,3,4c03,4 • c1+c2- • “High” branching ratio in c02 → c01 + - Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  9. Branching ratio c02 c02 c03,4 c02,3,4, c+1 c-2, c+2 c-2 M2 = 180 GeV m = -500 GeV M2 = 200 GeV m = -200 GeV Point1 Point2 Point2 Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden. m <0

  10. A/H→c20c20→c10c10 4negative m Br(A/H→c20c20) Br(A/H→c20c20) m m Br(c20 →c102) Br(c20 →c102 ) Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden. m m

  11. Sample of events • Signal • H → 4  • A → 4  • MSSM Background • → 4  • Standard Model Background • bbZ → 4  • tt → 4  • ZZ → 4  • Reference points: ( same BKMM) • MSSM Point 1 MA=500 GeV tanb=20 • MSSM Point 2 MA=600 GeV tanb=35 • MSUGRA Point A tanb=20 • MSUGRA Point B tanb=20 Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  12. MSSM particle masses Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  13. Simulation & reconstruction in ATLAS detector • ATLAS detector response has been full simulated taking into account the effetcts of energy loss, multiple scattering and showering in the detector through ATHENA interface. • SM background cross section , as signal are considered at LO approximation • Study at Lint =300 fb-1 scenario .( →Lint =100 fb-1) • The statistics used corrisponds to AT LEAST this luminosity. In some delicate points the statistics is increased up a factor 2, with exception tt background. Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  14. Muons preliminary preliminary • For A Sample m in events A/H→c20c20→m ....... preliminary Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  15. Electrons & E Tmiss • For A Sample in events A/H→c20c20→ e...... preliminary preliminary preliminary preliminary Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  16. ZZ and tt sample preliminary preliminary preliminary Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  17. Selection 1 part • Generation Event Filter: 4  → and |h| < 2.7, pT > 5GeV • Preselection cuts: • Trigger one:1 electron isolated E > 22 GeV or a m isolated > 20 GeV (1m20i or 1e22i) • pT > 5GeV • Isolation S pT< 6 GeV in cone DR=0.2 • Medium electron definition considered reconstruction • Selection • Lepton pair charge and flavour constrains 1-1+2 2+ Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  18. Selection 2 part • Selection cuts: • Impact significance parameter for m > 4 and e > 6 • pT1 > 8 GeV • 35 GeV<ETmiss < 130 GeV • Z veto : |Minv (+ -) –Mz| > 6 GeV tt Zbb, ZZ • 1st high energy lepton pT1, 2nd high energy lepton pT2 25 GeV <pT1 < 110 GeV • pT1 < 100 GeV and pT2 > 60 GeV • pT2 > 60 GeV ( only Set2 & SetA) • PTMin > 20 GeV • Njet 5 PTjet >20 GeV (with 1 track) • Minv (+ - + -) < 125 GeV (SetA) Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  19. Reference Point 1 Sample SIGNAL Back SM MSSM Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden. *s x brwithout box diagram 34.8 fb (weight 1.49)

  20. Set1:Cross Section & Br A,H Br4  ( |h| < 2.5, pT > 5GeV) s x Br 4  s A A A H H H Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden. preliminary preliminary preliminary

  21. Background effective cross section s x Br 4  s x Br 4  s x Br 4  preliminary preliminary s x Br 4  Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  22. Set 1-MSSM Background • s x Br 4  not depending from MA, as expected. The events processed at each tanb at MA= 500 GeV are used. • tH events studied at each point (tanb,MA) • Explored region: • tanb 5,8 and • 10-40 step 5 • MA 375-900 GeV • step 25 GeV Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  23. Set 1 Discovery plots at L = 300 fb-1 preliminary preliminary Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  24. Set 1 Discovery plots at L = 100 fb-1 • The discovery region for A/H→c20c20→4  + ETmiss can be accessible only after L=300fb-1. • No clear discovery possibilty at lower luminosity • The background are mainly ZZ and slepton pair and tt pair. preliminary Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  25. Set 2 :Cross Section & Br A,H Br4  ( |h| < 2.5, pT > 5GeV) s s x Br 4  A A A H H H preliminary preliminary preliminary Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  26. Background effective cross section s x Br 4  s x Br 4  A tanb =3 preliminary preliminary s x Br 4  H • tH background not anymore neglegible • LL background neglegible tanb =3 preliminary • Explored region: • Tanb 3 and • 5-50 step 5 • MA 375-900 GeV • step 25 GeV • low tan b region • Signal dominatedA→c20c20 Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  27. Set2 Discovery plots at L = 300 fb-1 preliminary preliminary Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  28. Set2 Discovery plots at L = 100 fb-1 preliminary preliminary Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  29. Conclusion of Set2 • The detection region of A/H→c02,3,4c02,3,4→4  + ETmiss and A,H →c+2c-1,2 →4 ±+ E Tmiss is accessible also with L=100fb-1. • The remaing background are mainly ZZ and tt pair, direct cc, tH± production is not neglegible. • Preliminary study also on MSUGRA has been performed, SetA, In this scenario the copious background is tt pair • The point at MA= 257 GeV and tan b= 20 has been studied . The significance achieved is after L =300fb-1 is  5 s. Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  30. Charged Higgs involvement Final state: Only 3 lepton +another lepton from a top decay Is not the best final state for a dedicated H- search….. Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  31. Charged Higgs role preliminary • The range of discovery is enlarged, extending the search to all MSSM Higgs(H/A/H±) respect to neutral H/A.. Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  32. Charged Higgs role preliminary preliminary • The range of discovery is enlarged, extending the search to all MSSM Higgs(H/A/H±) respect to neutral H/A.. Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

  33. Conclusion • Discover potential studyin MSSM neutral Higgs boson, A/H→ 4  + ETmiss in ATLAShas provided the first results. • A scan in (MA,tanb) plane with the the points dominated by c20c20 decays(Set1) andc2,30c2,3,40 decays(Set2) has been performed using full simulation of ATLAS detector • With Set1 parameters the possibilty of discovery of neutral MSSM Higgs are after L=300 fb-1, • With Set 2 the perspective are more encouraging even with L=100fb-1 • The inclusion of charged Higgs decay extends the possibility of discovery a MSSM Higgs even with L=100fb-1. • I would like to thank Stefano Moretti and Filip Mortgart for discussions and informations. • Many thanks to Karl Jakobs , who coming back from Uppsala2006 suggested me this interesting topic. MANY THANKS to JUNICHI TANAKA Simonetta Gentile, Charged Higgs, 2008,Uppsala, Sweden.

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