Revelation: Background and Commentary Written by Robert Jones - 2002
ZEUS Status DESY PRC, 30 October 2002 E. Tassi, NIKHEF Software/Detector status 2002 Running: 2002...
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Transcript of ZEUS Status DESY PRC, 30 October 2002 E. Tassi, NIKHEF Software/Detector status 2002 Running: 2002...
ZEUS StatusZEUS Status
DESY PRC, 30 October 2002DESY PRC, 30 October 2002E. Tassi, NIKHEFE. Tassi, NIKHEF
Software/Detector statusSoftware/Detector status 2002 Running:2002 Running:
Background studiesBackground studies Physics ResultsPhysics Results OutlookOutlook
E. Tassi - DESY PRC, 30 October 20022
ZEUS ComputingZEUS Computing
Computer farm:Computer farm:Recently upgraded with Recently upgraded with 40 Intel Xeon/2.2 GHz processors40 Intel Xeon/2.2 GHz processors - doubled system´s computing power- doubled system´s computing power
Mass Storage System:Mass Storage System:Moved from Moved from SSFSSF to to dCachedCache ( (DESY/FNAL)DESY/FNAL)
- cached access to the storage system- cached access to the storage system
and CPU upgrade have greatlyand CPU upgrade have greatly
improved turnaround of analysis jobsimproved turnaround of analysis jobs
16 Mio of events processed so far...16 Mio of events processed so far...
E. Tassi - DESY PRC, 30 October 20023
ZEUS Application SoftwareZEUS Application Software
ZeZeus us VisVisualizationualization PackagePackage
Since the first „slim release“Since the first „slim release“ rapidly becoming a maturerapidly becoming a mature productproduct
Among new featuresAmong new features Full event informationFull event information
Already an invaluable toolAlready an invaluable tool
Improved 2D/3D renderingImproved 2D/3D rendering New detectors includedNew detectors included -FTD/STT/RTD/MUON-FTD/STT/RTD/MUON Used as front-end of theUsed as front-end of the online event displayonline event display
E. Tassi - DESY PRC, 30 October 20024
ZEUS detector statusZEUS detector status
Zeus Micro Vertex DetectorZeus Micro Vertex Detector
Straw-Tube TrackerStraw-Tube Tracker
Photon Cal. and Lumi SpectrometerPhoton Cal. and Lumi Spectrometer
Detector operationalDetector operational - 2000 components re-commisioned- 2000 components re-commisioned - Since Feb. 22 could operate CTD- Since Feb. 22 could operate CTD (although at lower beam currents - Background)(although at lower beam currents - Background) Concentrate on new components:Concentrate on new components:
E. Tassi - DESY PRC, 30 October 20025
LUMI and STTLUMI and STT
LUMILUMI Photon Cal.Photon Cal. and and spectrometerspectrometer both both
taking data and measuring luminositytaking data and measuring luminosity Calibration/alignement/acceptance Calibration/alignement/acceptance studies on-going studies on-going
STTSTT Integrated in the data taking Integrated in the data taking STT s/w in the reconstruction suiteSTT s/w in the reconstruction suite After installation a few h/w problems After installation a few h/w problems were identified. Detailed plan to curewere identified. Detailed plan to cure them has been elaborated.them has been elaborated.
E. Tassi - DESY PRC, 30 October 20026
Micro Vertex Detector Micro Vertex Detector
SuccesfullySuccesfully taking data taking data MVD reconstruction codeMVD reconstruction code thoroughly exercised/tunedthoroughly exercised/tuned Global Tracking TriggerGlobal Tracking Trigger running and producingrunning and producing first resultsfirst results Preparation for the final Preparation for the final alignement well underwayalignement well underway
E. Tassi - DESY PRC, 30 October 20027
Background StudiesBackground Studies
Huge effort devoted by the collaboration (see ZN-02-018 and forthcoming addenda) Main concern: operating the CTD Background sources: positron-beam related: SR,e-gas proton-beam related: p-gas Our present understanding and possible remedies
E. Tassi - DESY PRC, 30 October 20028
Synchrotron radiation and e-gasSynchrotron radiation and e-gas Synchrotron RadiationSynchrotron Radiation Direct (marginal) and backscattered Direct (marginal) and backscattered photons entering CTD and producing photons entering CTD and producing ionizationionization Exploit detailed simulation suiteExploit detailed simulation suite Factor ~10 should be achievable by Factor ~10 should be achievable by implementing shielding measures andimplementing shielding measures and modification of beamline elementsmodification of beamline elements
Fairly good understanding of the problem..Fairly good understanding of the problem..
Design: C5a with integrated shieldDesign: C5a with integrated shield
e-gase-gas Origin of the problem...Origin of the problem... C5a reduced thickness:C5a reduced thickness: only factor 2 reductiononly factor 2 reduction Need improvement of the vacuum Need improvement of the vacuum
lower momentum e
E. Tassi - DESY PRC, 30 October 20029
proton-gasproton-gas Will become the main source of BG Will become the main source of BG when reducing SRwhen reducing SR MC simulation implementingMC simulation implementing p-gas (HERWIG minimum bias)p-gas (HERWIG minimum bias) - mainly sensitive to 20m from IP- mainly sensitive to 20m from IP - vacuum profile from MC/Data comp.- vacuum profile from MC/Data comp. Dynamic vacuumDynamic vacuum Marginal improvements fromMarginal improvements from modification of our beamlinemodification of our beamline
Need much improved vacuumNeed much improved vacuum (especially close to the IR)(especially close to the IR)
E. Tassi - DESY PRC, 30 October 200210
A Possible ScenarioA Possible Scenario
@ nominal Ie=58 mA @ nominal Ip=130 mA
tota
lto
tal
p-gas
e-gas
p-gas
e-gassynch synch
Ie=50ma
Ie~60mA Ip~130mA
E. Tassi - DESY PRC, 30 October 200211
Physics ResultsPhysics Results
Highlights:Highlights: QCD fits, High-Q2 NC and CC cross sectionsQCD fits, High-Q2 NC and CC cross sections DIS inclusive jet cross sections DIS inclusive jet cross sections Beauty productionBeauty production Deeply Virtual Compton ScatteringDeeply Virtual Compton Scattering Searches for isolated taus and missing PtSearches for isolated taus and missing Pt
HERA II Physics: see K. Long and P.SchleperHERA II Physics: see K. Long and P.Schleper last PRC´s presentationslast PRC´s presentations
ZEUS rich physics program:ZEUS rich physics program: 45 contributed papers to ICHEP 200245 contributed papers to ICHEP 2002
E. Tassi - DESY PRC, 30 October 200212
ZEUS-Oep,110 pb-1
ZEUS-S uv,dv
QCD Fit, High-QQCD Fit, High-Q22 NC and CC NC and CC
ZEUS NLO QCD FitZEUS NLO QCD Fit Now publishedNow published Zeus PDFs with uncertainties and Zeus PDFs with uncertainties and ss
Zeus-Only valence PDFsZeus-Only valence PDFs
High Q2 NC and CC analysesHigh Q2 NC and CC analyses e+p NC/CC approaching completione+p NC/CC approaching completion - will complete ZEUS HERA I inclus.cross sections measurements at high-Q- will complete ZEUS HERA I inclus.cross sections measurements at high-Q22
Important input for:Important input for: -Testing the EW sector of the SM-Testing the EW sector of the SM -Learn more about valence PDFs at high-x-Learn more about valence PDFs at high-x
ZEUS/H1 working group established and doing good progress...ZEUS/H1 working group established and doing good progress...
s(Mz) =0.1166 0.00080.00320.00360.0018 uncor. corr. norm. model
E. Tassi - DESY PRC, 30 October 200213
NC DIS inclusive jet cross sectionsNC DIS inclusive jet cross sections Direct sensitivity to s and the gluon density Reduced theoretical unc. w.r.t. dijet cross sections (infrared insensitive)
Analysis: Single and double differential cross measured for Q2 > 125 GeV2 and EB
T,jet > 8 GeV and compared to NLO QCD predictions.
As a result of a QCD fit: precise determination of s (MZ)
96/97 data set, incl. K in the Breit frame
E. Tassi - DESY PRC, 30 October 200214
NC DIS inclusive jet cross sectionsNC DIS inclusive jet cross sections
Agreement at high-Q2 and high-EAgreement at high-Q2 and high-ET,jetT,jet
E. Tassi - DESY PRC, 30 October 200215
Inclusive jet cross sectionsInclusive jet cross sections
E. Tassi - DESY PRC, 30 October 200216
Beauty ProductionBeauty Production
Rich testing ground of QCDRich testing ground of QCD - NLO pQCD:- NLO pQCD: FMNR (PHP), HVQDIS (DIS)FMNR (PHP), HVQDIS (DIS)
- DGLAP vs CCFM evolution- DGLAP vs CCFM evolution - Fragmentation- Fragmentation
ZEUS contributing with a setZEUS contributing with a setof precise measurementsof precise measurementsin the PHP and DIS regimes in the PHP and DIS regimes
Boson-Gluon Fusion (direct)
Gluon-Gluon Fusion (resolved photon)
E. Tassi - DESY PRC, 30 October 200217
Beauty productionBeauty production
b visible cross sections in PHPb visible cross sections in PHP
(ep(epbbXbbX e Jet Jet e Jet Jet X) X)
Q2 <1 GeVQ2 <1 GeV22, 0.2< y <0.8, 0.2< y <0.8At least two jets in the Lab frame with:At least two jets in the Lab frame with: PPT,jet1(jet2)T,jet1(jet2) > 7(6) GeV, > 7(6) GeV, jetjet < 2.5 < 2.5 At least on muon with:At least on muon with: ppT,T, > 2.5 GeV, -1.6 < > 2.5 GeV, -1.6 < <2.3 <2.3
New result:96/00 ~98 pb-1
3 times more statistics
Data/NLO ~1.4Data/NLO ~1.4Agreement within uncertaintiesAgreement within uncertainties
E. Tassi - DESY PRC, 30 October 200218
Beauty productionBeauty production
(ep(epbbXbbX e Jet e Jet X) X)
QQ22 < 2 GeV < 2 GeV22, 0.05< y <0.7, 0.05< y <0.7At least one jet in the Breit frame with:At least one jet in the Breit frame with: EET,jet1T,jet1 > 6 GeV, > 6 GeV, jetjet < 2.5 < 2.5 At least one muon with:At least one muon with: ppT,T, > 2.0 GeV, 30 > 2.0 GeV, 30ºº < < < 160 < 160ºº
First diff. B visible cross sections in DISFirst diff. B visible cross sections in DIS
New result: 99/00 ~ 60 pbNew result: 99/00 ~ 60 pb-1-1
Agreement with NLOAgreement with NLO
E. Tassi - DESY PRC, 30 October 200219
Deeply Virtual Compton Deeply Virtual Compton ScatteringScattering
Simple process:Simple process:
a diffractively produced a diffractively produced real photonreal photon
Great theoretical interest:Great theoretical interest: - Generalized Parton Distributions- Generalized Parton Distributions ....but also Color Dipole Models,....but also Color Dipole Models, VM productionVM production
(*p p) measured as afunction of Q2 and W in e+p and e-p
E. Tassi - DESY PRC, 30 October 200220
DVCSDVCS
No differences between e+ and e- samplesNo differences between e+ and e- samples Steep rise with W Steep rise with W hard underlying processhard underlying process
E. Tassi - DESY PRC, 30 October 200221
DVCSDVCS
Data precise enough to start discriminating differentData precise enough to start discriminating differenttheoretical models. See also hep-ph/0208160theoretical models. See also hep-ph/0208160
E. Tassi - DESY PRC, 30 October 200222
Search for isolated Search for isolated s s Prompted by high pt-lepton searchesPrompted by high pt-lepton searches (electron and muon channels)(electron and muon channels) H1 see excess, ZEUS compatibleH1 see excess, ZEUS compatible with the Standard Model with the Standard Model
Look at the Look at the channel... channel...
Search for hadronic decays (65% BR, predominantly in one charged hadron) Analysis based on a Multi-observable discrimination technique (use 6 jet-shape releted variables) Aim: separate -induced jets from quark- and gluon-initiated jets (-jets pencile like, low charged particle multiplicity and charge 1)
E. Tassi - DESY PRC, 30 October 200223
Search for isolated Search for isolated ss
ResultsResults
2 events observed (P2 events observed (PTT>25)>25)
0.12 0.12 0.02 expected from SM 0.02 expected from SM
E. Tassi - DESY PRC, 30 October 200224
Summary and OutlookSummary and Outlook
Zeus taking data and in good shapeZeus taking data and in good shape Huge effort devoted to background studiesHuge effort devoted to background studies ZEUS rich physics program well underway ZEUS rich physics program well underway Looking forward to the forthcoming dataLooking forward to the forthcoming data taking period...taking period...
E. Tassi - DESY PRC, 30 October 200225
spoolspoolsynch+e-gas
synche-gas
CTD ~ 7*Ie+1.26*Ie 1.3
CTD ~ 1.17*Ie+0.63*Ie 1.3
e-gas
synch