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Generation of samples for VBF H 0 -->ZZ*-->bbll

Generation of samples for VBF H 0 -->ZZ*-->bbll. Signal : m H = 130 : Xsec = 1.6 fb, Pythia, > 200K events. m H = 140 : Xsec = 2.6 fb, Pythia, 200K events. m H = 150 : Xsec = 2.9 fb, Pythia, 200K events. Backgrounds :

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Generation of samples for VBF H 0 -->ZZ*-->bbll

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  1. Generation of samples for VBF H0-->ZZ*-->bbll Signal : mH = 130 : Xsec = 1.6 fb, Pythia, > 200K events. mH = 140 : Xsec = 2.6 fb, Pythia, 200K events. mH = 150 : Xsec = 2.9 fb, Pythia, 200K events. Backgrounds : bb : Xsec = 3.0 1011 fb, MCatNLO+JIMMY, > 400K events tt : Xsec = 6.9 105 fb, MCatNLO+JIMMY, >700K events Zbb : Xsec(qq-->Zbb) = 8.6 103 fb, AcerMC + Pythia , ~ 300K events Xsec(gg-->Zbb) = fb, AcerMC + Pythia , 450K events ZZ : Xsec = MCatNLO + JIMMY : in progress Z/gamma : Xsec = MCatNLO + JIMMY : in progress MC@NLO files generated but problem to produce ATLFAST CBNT.

  2. Signal distributions for mH=130 at generation level High mass of VBF jet-system Wide separated jets coming from VBF

  3. Signal eta distributions (2) Central leptons Central B jets

  4. Signal mass distributions (3) Compatiblewith virtual Z Mass window

  5. Signal Pt distributions (4)

  6. bb background generated with MC@NLO Too low statistics (3.1 10-3 % of total). 2 ideas to improve that : 1/ ~ 84% of leptons come from b hadrons. Idea = to force the semileptonic decays of the b hadrons.  How to force the decays in HERWIG ? Up to now, not found. 2/ Cut on the hard process Pt : Is it still ok with a 2 --> 3 process ?  Pt distribution shows no difference before and after cut.

  7. Event selection • Precuts : • 2 b jets, |η| < 2.7, Pt > 5 GeV/c • 2 leptons, |η| < 2.7, Pt > 5 GeV/c • The lepton pair with the highest Pt • The b-jet pair with the reconstructed mass the closest to Z mass. • Dilepton system mass compatible with a virtual Z mass : mllє [10;70] • Trigger : • electrons : At least one Pt > 25 GeV/c or 2 Pt > 15 GeV/c • muons : At least one Pt > 20 GeV/c or 2 Pt > 10 GeV/c • VBF jets : • 2 jets, η1.η2 < 0, |Δη| > 4, the pair with the highest mass. • mjj > 500 GeV/c2 • Possible Additionnal cuts : • Ptmiss < C_ Ptmiss : against tt background. • mll, Ptb, ΔRlland ΔRbb.

  8. Efficiencies (mH = 130 GeV/c2)

  9. Distributions (mH = 130 GeV/c2) (1/2) Cut on Ptmiss

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