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On the possibility to observe with CMS a moderately heavy Higgs decaying via H  ZZ  ll nn

On the possibility to observe with CMS a moderately heavy Higgs decaying via H  ZZ  ll nn. Leonid G. Levchuk Kharkov Institute of Physics & Technology. Motivation. Search for physics suggesting importance of hadron calorimetry H ZZll nn has ~6 times greater BR compared to H ZZ4l

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On the possibility to observe with CMS a moderately heavy Higgs decaying via H  ZZ  ll nn

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  1. On the possibility to observe with CMS a moderately heavy Higgs decaying viaHZZllnn Leonid G. Levchuk Kharkov Institute of Physics & Technology

  2. Motivation • Search for physics suggesting importance of hadron calorimetry • HZZllnn has ~6 times greater BR compared to HZZ4l • Some light could be shed on physics of ZZ interaction

  3. Previous studies • N.Stepanov, CMS-TN/93-087 (1993); N.Stepanov and S.Abdullin, CMS-TN/94-178 (1994); I.Gaines, D.Green, S.Kunori, J.Marrafino, J.Womersley, and W.Wu, CMS-TN/95-84 (1995) heavy (MH>500 GeV) Higgs observability via HZZll was studied;irreducible background (IB) due to ZZ/ZW production thwarts H observation • L.Levchuk, 6th annual RDMS CMS collaboration meeting (MSU, Moscow, 2001); L.Levchuk, D.Soroka, P.Sorokin, V.Trubnikov, and S.Zub, 7th annual RDMS CMS collaboration meeting (IHEP, Protvino, 2002)extension to MH=200250 GeV; ways to eliminate IB

  4. Simulation tools Background contributions • PYTHIA (Ver. 6.158) • CMSJET (Ver. 4.703) • Z+jets • ZZ • ZW irreducible background

  5. 1-st level (“tentative”) cuts: ETmiss > 60 GeV, 2 leptons such that : |l| < 2.4, pTl >20 GeV, PTll > 40 GeV, |MZ-Mll| < 5 GeV At threshold ofHZZdecay, (MTZZ 2MZ)1/2 | |

  6. “Loose” cuts (“A”) 1-st level (“tentative”) cuts: ETmiss > 60 GeV, 2 leptons such that : |l| < 2.4, pTl >20 GeV, PTll > 40 GeV, |MZ-Mll| < 5 GeV Elimination of the IB: No b-jets: Nb-jets=0

  7. “Hard” cuts (“C”) 1-st level (“tentative”) cuts with loosed cut on ETmiss: ETmiss > 40 GeV, 2 leptons such that : |l| < 2.4, pTl >20 GeV, PTll > 40 GeV, |MZ-Mll| < 5 GeV Elimination of the IB: No b-jets: Nb-jets=0 Extra criteria (I): Extra criterion (II) – selection of single-jet events: Nj=1 , 1.0<|j| < 4.5, pTj >40 GeV

  8. Current status and plans for nearest future • Publication of the preliminary results • L.G.Levchuk, P.V.Sorokin and S.Kunori, “On the possibility to observe a heavy Higgs via HZZll decays at CMS”, CMS Note (or CMS_IN?) – in preparation • Search with “fast” MC for kinematical criteria providing a better signal/background ratio • In case of success, preparation for “detailed” (OSCAR or CMSIM) simulation & ORCA reconstruction • Check for reliability and degree of the IB suppression • Simulations with a generator other than PYTHIA (HERWIG, …?) • Simulations of the non-resonant ZZ/ZW production accompanied by high-pT jets based on 23 hard processes (COMPHEP, …?) • NLO calculations of the non-resonant ZZ/ZW production (MC@NLO_2.2 [http://www.hep.phy.cam.ac.uk/theory/webber/MCatNLO], …? ) • Consideration of the 23 Higgs production • A generator for a combined treatment for both WBF and QCD 23 mechanisms of Higgs production – under development

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