1 / 9

Generation of VBF H0->ZZ*->bbll Signal with Additional Backgrounds

This text discusses the generation of signal samples for VBF H0->ZZ*->bbll with different masses and cross sections, as well as the inclusion of backgrounds such as bb, tt, Zbb, and ZZ. Efficiencies, distributions, and event selection criteria are also examined.

pamelahernandez
Télécharger la présentation

Generation of VBF H0->ZZ*->bbll Signal with Additional Backgrounds

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related