Leonid G. Levchuk -- 9th Annual CMS/RDMS Meeting, Minsk, Belarus

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Search for heavy Higgs in decays HZZlland current status of the KIPT

CMS Linux Cluster

L. Levchuk, D.Soroka, P.Sorokin, M. Voronko, and S. ZubKharkov Institute of Physics & Technology, 61108 Kharkov, Ukraine

2Leonid G.Levchuk – 9th Annual CMS/RDMS Meeting, Minsk, Belarus 30 Nov 2004

KKIIPPTTPhysics motivation

So far, no evidence for light (M120 GeV/c2) SM Higgs HZZll has ~6 times greater BR

compared to HZZ4l Search for resonances in ZZ system

3Leonid G.Levchuk – 9th Annual CMS/RDMS Meeting, Minsk, Belarus 30 Nov 2004

KKIIPPTTPrevious 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 HZZll was studied L.Levchuk et al., 6th, 7th and 8th Annual RDMS/CMS collaboration meetings (2001-2003) MH=200250 GeV/c2; ways to eliminate IB by tuning cuts to qqHq & ggHg

Goals of this studyGoals of this study Optimization (tuning to WBF qqHqq, etc.) of event selection criteria for MH~200 GeV/c2

Extension to MH=250450 GeV/c2

4Leonid G.Levchuk – 9th Annual CMS/RDMS Meeting, Minsk, Belarus 30 Nov 2004

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Simulation tools PYTHIA (Ver. 6.205) CMSJET (Ver. 4.703)

Z+jets ZZZW

Background contributions_

t t

““Irreducible” Irreducible” backgroundbackground

75 Mevts75 Mevts for for Z+jets and 10 Mevts for t t have been generated

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5Leonid G.Levchuk – 9th Annual CMS/RDMS Meeting, Minsk, Belarus 30 Nov 2004

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Suppression of background toSuppression of background to HH00ZZ00ZZ00eeee(() + ) + eventsevents

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ETmiss > 30 GeV;

2 leptons such that : |l|<2.4, pTl >20 GeV/c, pT

ll>30 GeV/c, |MZ-Mll| < 5 GeV/c2; pT

llpTmiss  90 (jets); no b-jets (pT

jet >20 GeV/c);

Njets  1 or 2 for pTjet >20 GeV/c, 1.0  |jet|  4.5

For Njets  1:

ETmiss  40  GeV; pT

llpTjet  120; pT

misspTjet  120;

pl1pl2  60; pTl1pT

l2  90;

For Njets  2:

|jet1– jet2|  4.2; M jj  600  GeV/c2; 2.0  | jet|  4.5; pT

jet1pTjet2  90; jet1jet2  0; cos(pl1pl2)  0.4

“2nd

leve

l” c

uts

“1st

leve

l” c

uts

((MMH H = 200 GeV/c= 200 GeV/c22))

6Leonid G.Levchuk – 9th Annual CMS/RDMS Meeting, Minsk, Belarus 30 Nov 2004

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HH00ZZ00ZZ00eeee(() + ) + vs. backgroundvs. background

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7Leonid G.Levchuk – 9th Annual CMS/RDMS Meeting, Minsk, Belarus 30 Nov 2004

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“Combined” event selection criteria

8Leonid G.Levchuk – 9th Annual CMS/RDMS Meeting, Minsk, Belarus 30 Nov 2004

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“1-st level” cuts:ET

miss > 60 GeV; 2 leptons such that : |l| < 2.4, pT

l >20 GeV/c, pT

ll > 40 GeV/c, |MZ-Mll| < 6 GeV/c2; no b-jets for pT

jet >30 GeV/c; no jets for pTjet >100 GeV/c

“2-nd level” cuts:N jets > 0, 30 GeV/c < pT

jet < 100 GeV/c

Suppression of background toSuppression of background to HH00ZZ00ZZ00eeee(() + ) + eventsevents

((MMH H = 400 GeV/c= 400 GeV/c22))

9Leonid G.Levchuk – 9th Annual CMS/RDMS Meeting, Minsk, Belarus 30 Nov 2004

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HH00ZZ00ZZ00eeee(() + ) + vs. backgroundvs. background__

10Leonid G.Levchuk – 9th Annual CMS/RDMS Meeting, Minsk, Belarus 30 Nov 2004

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(current status)

11Leonid G.Levchuk – 9th Annual CMS/RDMS Meeting, Minsk, Belarus 30 Nov 2004

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Performances:Performances: 11 nodes (22 CPU’s, 38 Gflops), 2.5 TB HDD11 nodes (22 CPU’s, 38 Gflops), 2.5 TB HDD

LCG Middleware:LCG Middleware: ver. LCG-2_2_0 installed and configuredver. LCG-2_2_0 installed and configured

Production in 2004: Production in 2004: 150 Kevts (CMKIN150 Kevts (CMKINCMSIMCMSIMHITS) generated HITS) generated

and transferred to CERNand transferred to CERN

KIPT CMS Cluster (KCC)KIPT CMS Cluster (KCC)

KCC is a part of the MOSCOW Distributed RC KCC is a part of the MOSCOW Distributed RC KCC resources are allocated to CMS jobs exclusivelyKCC resources are allocated to CMS jobs exclusively

12Leonid G.Levchuk – 9th Annual CMS/RDMS Meeting, Minsk, Belarus 30 Nov 2004

KKIIPPTTConclusions & plans

The results suggest that heavy (MH=200500 GeV/c2) Higgs can be observed with CMS in decays HZZll

this has been illustrated by fast MC simulation for MH close to HZZ 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 23 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