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Search for heavy Higgs in decays H  ZZ  ll nn and current status of the KIPT CMS Linux Cluster

Search for heavy Higgs in decays H  ZZ  ll nn and current status of the KIPT CMS Linux Cluster. L. Levchuk , D.Soroka, P.Sorokin, M. Voronko, and S. Zub Kharkov Institute of Physics & Technology, 61108 Kharkov, Ukraine. Physics motivation. So far, no evidence for light

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Search for heavy Higgs in decays H  ZZ  ll nn and current status of the KIPT CMS Linux Cluster

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  1. Search for heavy Higgs in decays HZZllnn and current status of the KIPT CMS Linux Cluster L. Levchuk, D.Soroka, P.Sorokin, M. Voronko, and S. Zub Kharkov Institute of Physics & Technology, 61108 Kharkov, Ukraine

  2. Physics motivation • So far, no evidence for light (M120 GeV/c2) SM Higgs • HZZllnn has ~6 times greater BR compared to HZZ4l • Search for resonances in ZZ system

  3. Previous studies • N.Stepanov, CMS-TN/93-087 (1993); I.Gaines, D.Green, S.Kunori, J.Marrafino, J.Womersley, and W.Wu, CMS-TN/95-84 (1995); … heavy (MH>500 GeV/c2) Higgs observability via HZZll was studied • L.Levchuk et al., 6th, 7th and 8th Annual RDMS/CMS collaboration meetings (2001-2003) MH=200250 GeV/c2; ways to eliminate IB by tuning cuts to qqHq & ggHg Goals of this study • Optimization (tuning to WBF qqHqq, etc.) of event selection criteria for MH~200 GeV/c2 • Extension toMH=250450 GeV/c2

  4. Simulation tools Background contributions • PYTHIA (Ver. 6.205) • CMSJET (Ver. 4.703) • Z+jets • ZZ • ZW “Irreducible” background _ 75 Mevts forZ+jets and 10 Mevts fort t have been generated

  5. Suppression of background to H0Z0Z0ee() +  events _ (MH = 200 GeV/c2) ETmiss > 30 GeV; 2 leptons such that : |l|<2.4, pTl >20 GeV/c, pTll>30 GeV/c, |MZ-Mll| < 5 GeV/c2; pTllpTmiss 90(jets); nob-jets (pTjet>20 GeV/c); Njets 1 or 2 for pTjet>20 GeV/c, 1.0  |jet|  4.5 “1st level” cuts For Njets 1: ETmiss 40  GeV; pTllpTjet 120; pTmisspTjet 120; pl1pl2 60; pTl1pTl2 90; For Njets 2: |jet1– jet2|  4.2; Mjj 600  GeV/c2; 2.0  |jet|  4.5; pTjet1pTjet2 90; jet1jet2 0; cos(pl1pl2)  0.4 “2nd level” cuts

  6. _ H0Z0Z0ee() +  vs. background

  7. “Combined” event selection criteria

  8. Suppression of background to H0Z0Z0ee() +  events (MH = 400 GeV/c2) “1-st level” cuts: ETmiss > 60 GeV; 2 leptons such that : |l| < 2.4, pTl >20 GeV/c, pTll > 40 GeV/c, |MZ-Mll| < 6 GeV/c2; nob-jets for pTjet>30 GeV/c; no jets for pTjet>100 GeV/c “2-nd level” cuts: N jets > 0, 30 GeV/c < pTjet < 100 GeV/c

  9. _ H0Z0Z0ee() +  vs. background

  10. (current status)

  11. KIPT CMS Cluster (KCC) Performances: 11 nodes (22 CPU’s, 38 Gflops), 2.5 TB HDD LCG Middleware: ver. LCG-2_2_0 installed and configured Production in 2004: 150 Kevts (CMKINCMSIMHITS) generated and transferred to CERN KCC is a part of the MOSCOW Distributed RC KCC resources are allocated to CMS jobs exclusively

  12. Conclusions & plans • The results suggest that heavy (MH=200500 GeV/c2) Higgs can be observed with CMS in decays HZZllnn • this has been illustrated by fast MC simulation for MH close to HZZ decay threshold as well as for very heavy (MH=400 GeV/c2) Higgs • conclusions seem to be valid to the extent, at which one believes PYTHIA and CMSJET • use/development of an alternative generator, which would take into account 23 hard processes of non-resonant ZZ/ZW production is desirable • Simulations with FAMOS and (prob.) OSCAR are planned • Current status of the KIPT CMS Cluster (KCC) allows us to proceed with participation in CMS MC production • LCG-2 middleware has been installed and configured • Considerable increase of the KCC capacity is planned to provide KIPT participation in CMS data analysis • bandwidth of KIPT internet channel is still unsatisfactory; work is under way to improve the situation

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