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Progress for search of neutral Supersymmetric Higgs boson h/A bb h 0 /A (h 0 /A  m + m - )

Progress for search of neutral Supersymmetric Higgs boson h/A bb h 0 /A (h 0 /A  m + m - ). Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile , Giovanni Nicoletti Laboratori Nazionali di Frascati , Università di Roma La Sapienza, INFN. m. m. n. n. Outline. Preselection

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Progress for search of neutral Supersymmetric Higgs boson h/A bb h 0 /A (h 0 /A  m + m - )

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  1. Progress for search of neutral Supersymmetric Higgs boson h/A bb h0/A(h0/Am+m-) Halina Bilokon,Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Laboratori Nazionali di Frascati, Università di Roma La Sapienza, INFN Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  2. m m n n Outline • Preselection • Selection : • b-tag • muons • b-jets • Invariant mass • m -isolation • Conclusions & planning • Top decay:  100% t  bW • Background: • bb Z→ m m • tt →bb m m • ZZ →bbm m Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  3. Selection • Preselection cuts: • At least a pair of opposite muons with pt > 10 GeV and |h| < 2.5 • At least a pair of jets with ET > 10 GeVand|h| < 2.5 • Selection • At least 1 b-jets (pT > 15 GeV & b-tag weight>1) • ETmiss < 45 GeV • 25 GeV < PTm1 < 95 GeV • 20 GeV < PTm2 < 60 GeV for tt background • PTb2 < 40 GeV • PTb1 < 70 GeV • Final Cut • Minv( m+m-) +/- DM (GA0, Gh0, sm) ( sm= exp. massres.) • Isolation SPTtrack < 5 GeV around a cone DR<0.2 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  4. Sample *Corresponding tohalf luminosity Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  5. Nm 2 Number of muons: no cut h0 A bbZ→mm tt ZZ x 0.5 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  6. PT of muons: no cut pTm> 10 GeV h0 bbZ→mm tt ZZ x 0.5 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  7. At least a pair of m+m- with pt > 10 GeV |h| < 2.5 *Corresponding tohalf luminosity Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  8. Njet 2 Number of jets: after 1 cut h0 A tt ZZ bbZ→mm x 0.5 x 0.5 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  9. A pair of jetswith pt > 10 GeV |η| < 2.5 P R E S E L E C T I O N *Corresponding tohalf luminosity Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  10. After preselection: Number of Jets (DR=0.7) Nev h0 A Nev Njet Njet Nev Nev bbZ→mm tt Njet Njet Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  11. After preselection: jets pT (DR=0.7) Nev h0 A Nev <pT> ~25 MeV <pT> ~26 MeV Nev PT(MeV) Nev PT(MeV) bbZ→mm tt <pT> ~53 MeV <pT> ~35 MeV PT(MeV) PT(MeV) Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  12. At least 1 b-jets (pT > 15 GeV & b-tag weight>1) *Corresponding tohalf luminosity Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  13. m m n n After b-tag cut: ETmiss ETmiss < 45 GeV h0 A <ET>= 21.8 GeV <ET>= 23.7 GeV bbZ→mm tt <ET>= 67.1 GeV <ET>= 27.5 GeV Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  14. ETmiss < 45 GeV m m n n *Corresponding tohalf luminosity Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  15. m m n n After ETmiss:the most energetic m PTm1 25 GeV<pTm1 < 95 GeV h0 A tt bbZ→mm x 0.5 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  16. 25 GeV<pTm1 < 95 GeV m m n n *Corresponding tohalf luminosity Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  17. m m n n After PTm1 :the 2nd most energetic m PTm2 20 GeV<pTm1 < 60 GeV h0 A h0 bbZ→mm tt tt x 0.5 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  18. 20 GeV<pTm1 < 60 GeV m m n n Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN. *Corresponding tohalf luminosity

  19. m m n n After PTm cut: 2nd most energetic b PTb2 pTb2 < 40 GeV A h0 bbZ→mm tt x 0.5 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  20. pTb2< 40 GeV m m n n *Corresponding tohalf luminosity Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  21. m m n n After PTb2 cut: most energetic b PTb1 pTb1 < 70 GeV h0 A bbZ→mm tt x 0.5 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  22. pTb1< 70 GeV m m n n Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN. *Corresponding tohalf luminosity

  23. After tt cuts:Invariant mass distributions h0 A bbZ→mm tt x 0.5 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  24. Mass selection window • Fit results are consistent with detector mass resolution and natural with of particle • k = -820 MeV measured at Z mass • f = standard deviation fraction corresponding to chosen probability: (e.g. f =2) • Where Gtoth0 =3.31 GeV GtotA = 4.28 GeV • s m= 2.6% measured at Z mass Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  25. Invariant mass h0 A bbZ→mm tt x 0.5 Fit results are consistent with detector mass resolution and natural with of particle Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  26. |Minv|< |Mh/A± window| Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN. *Corresponding tohalf luminosity

  27. After invariant mass cut:isolation SPT for tracks in D R < 0.2 SPT < 5 GeV see Louis Flores Presentation Atlas week 28.10.05 SPT < 5 GeV tt h0 Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  28. Isolation SPT < 5 GeV Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN. *Corresponding tohalf luminosity

  29. Conclusions • The possibility for a discovery of the neutral MSSM Higgs in bb A/h0→mm has been investigated in a test point of MSSM parameter space (tanb, mA): mA=110.3 GeV, mh0 =109.25 GeV • A study with considering Zbb, tt, and ZZ background led to a significance Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  30. Next future • Background subtraction method using bbZ→ e+ e- sample • Consider other possible discriminator variable • Develop an estimator in order to approach a near possible the Z peak • Scan (tanb, mA) plane • b-tag improvement (difficult) Credit to Giovanni Nicoletti. without him this work can never done Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  31. Riserve Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  32. after 1 cut bbZ→mm bbZ→mm tt x 0.5 x 0.5 tt Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

  33. h0→ m+m- Study of sample: Jets Z → m+m- Number of jets Number of jets <ETgen> ~ 20 GeV <ETgen> ~ 26 GeV ET jets ET jets Halina Bilokon, Vitaliano Chiarella, Simonetta Gentile, Giovanni Nicoletti Higgs Meeting 14 December 2005,CERN.

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