ZZEEUUSS statustatuss reprepoortrt -- recenrecentt resuresultslts SS..CChekanovhekanov ((AANNL) for the ZEUS Colllaboratiion DESY PRC review (October 28, 2004)
• Data taking and running conditions • Detector status • Physics Highlights • Summary
CC DIS at Q2~ 3000 GeV2 DDaatata tatakkiningg:: 22000033--22000044
Total gated: ~45 pb-1
Gated/HERA delilivered ~ 54%
Nearlly alll taken data can be used for physicics
All detectors are functional
Gated/MVD > 95% Gated/STT > 95%
S.Chekanov, DESY PRC review (Oct 2004) 2 ZEUZEUSS ddaatata tatakkiningg eefficfficieiennccy-y-II
Signiifiicant iimprovements during Jully-August Effiiciency went up since May due: better beam conditions (better vacuum, less spikes) improvements in DAQ/trigger Remaiiniing iineffiiciency: ~10% - HERA initial luminosiity tuning present ~5-8% - HV trips in central tracking (CTD) ~5-8% - DAQ problems Room for further iimprovements: speed up run starts reduce DAQ problems Efficiency (2000) reduce sensitiviity to CTD HV trips
Last ZEUS real efficiency 80-90% PRC
S.Chekanov, DESY PRC review (Oct 2004) 3 ZEUZEUSS ddaatata tatakkiningg eefficfficieiennccy-y-IIII Typiicall trigger dead tiime was 5-10% iin May (at llast PRC): removiing very busy events due to beam gas colllliisions from the trigger chaiin biiggest iimprovement - regenerated pumps iin June ✔ vacuum was improved at least by a factor two
Current trigger dead time ~ 1-2% up to Ie~50 mA & Ip~100 mA
Commissioniing of Glloball Tracking Trigger (GTT) at second-levell trigger fiiniished: iincludes iinformatiion from CTD, STT & MVD: ✔ better beam gas rejection and physics filters ✔ extend to forward region ✔ improve vertex resolution ✔ potentially can reduce trigger rates by ~15-30% some physics fiillters allready use the GTT ✔ allows heavy-flavor tagging on-line in the SLT fullll operatiion for e- runniing
S.Chekanov, DESY PRC review (Oct 2004) 4 22000033/2/2000044 ddaatata tatakkiningg New components:
Silliicon Miicro-Vertex-Detector (MVD)
New forward tracking wiith STT
New tracking trigger Beauty candidate: 2 jets + 2 muons
J/Psi candidate
New data are already an important part of ongoing physics program (see ICHEP04) → will be discussed in context of particular physics topic
S.Chekanov, DESY PRC review (Oct 2004) 5 StaStatutuss ooff MMVDVD && LLuummininoossityity mmoonnitoitorrss
47 M events collllected wiith MVD No big radiiatiion dose during May-August Detector iis iin good shape Relliiable detector operatiion → see physics resullts llater
Lumi spectrometer Shielding upgrade + new set of radiiatiion moniitors Lumi callorimeter Good agreement witith Lumi spectrometer
NC DIS(Q2>200) / Lumi (nb-1)
S.Chekanov, DESY PRC review (Oct 2004) 6 TaTakkiningg ddaatata wwithith STTSTT
● STT buiillt to iimprove relliiabiilliity and effiiciency of tracking iin forward diirectiion ● STT/FRTD runniing at nominall HV during 2004 > 95% effiiciency ● Angullar coverage matches wellll wiith MVD and starts (θ < 23º) where CTD has llow acceptance
● MVD/STT matchiing iis iin progress
✔ With event vertex one can reach about 10% accuracy for 1-5 GeV
● STT was iincorporated iinto GTT & TLT (software and hardware are ready)
Good STT-CTD-MVD matching:
90-95% efficiency for isolated tracks
S.Chekanov, DESY PRC review (Oct 2004) 7 RReessuultslts ooff HHERERAA sshhuutdtdoowwnn ((AuAugg--SeSepp))
Generall and preventivive mainintenance and detector repaiirs
Calorimimeter:
smallllest number of UCAL bad channells for the llast 6 years Lumi detectors:
Spectrometer: addititiional shiielldining agaiinst synchrotron radiiatiion
Callorimeimeter: some ellectronics has been repaireired Feedbox/Sollenoiid: moniitoring was iimproved DAQ and trigger iimprovements
ZEUS is ready for data taking
S.Chekanov, DESY PRC review (Oct 2004) 8 MMaaggnneett hheeaatintingg bbyy STTSTT
It was found that: STT ellectroniics has iinsuffiiciient coolliing Operatiion of STT ellectroniics can llead to temporary leaks iin sollenoiid iinsullatiion vacuum A serious sollenoiid faiillure cannot be repaiired in a short tiime STT stays off for now Investiigatiions are on-goiing
S.Chekanov, DESY PRC review (Oct 2004) 9 ZEUZEUSS GGrridid HERA-II data rates create strong iincrease of MC productiion demand ATLAS Need access to grid resources ZEUS At the same tiime, keep the “tradiitiionall” productiion sites (funnel) 0.6 M events allready produced - samplles pass standard DQM & are iin use for physics anallysis ● Transparent iintegratiion of tradiitiionall Jobs per VO (snapshot at RAL) productiion system & grid The ZEUS Gateway Concept KEK ZEUS Integrated Rutherford Production System
s ZEUS te
si Montreal l Grid e
n RAL n Tel Aviv Gateway Fu Bonn Scotgrid ... DESY ...
S.Chekanov, DESY PRC review (Oct 2004) 10 PhyPhysisicscs outoutputput
ZEUS
SLAC SPIRES-HEP database s 40
me CDF i
t 35
CLEO 0 30 ZEUS 0 OPAL 1
45 papers submitted to ICHEP04 25 ALEPH > H1
d 20
27 papers – new results e L3 t 15 BaBar ci D0 9 papers finished in 2004 s 10
n DELPHI o
i 5 SLD t HERMES
ca 0 i l b
u collaboration p
ZEUS papers are among most cited in literature
S.Chekanov, DESY PRC review (Oct 2004) 11 ZZEUEUSS phyphysisicscs programprogram
Proton structure, PDF Eleclectroweak unificicationion Jet productionion - QCD
s determinatinationion photon struucturere Dififfractionion Heavy fllavor physicics (charm & beauty) Search for new physicics Particiclele productionion pentaquarks
Q2 = -q2: 4-momentum transfer squared x: fraction of proton momentum carried by quark
S.Chekanov, DESY PRC review (Oct 2004) 12 NNLOLO QQCCDD analanalyysisiss andand PDPDFF BGF process
Inclusive DIS jets
Dijets in PHP
HERA data at high x are still less precise than fixed-target experiments Fixed-target experiments suffer from systematic uncertainties and rigorous treatment of uncertainties is difficult Include jet observables measured at ZEUS - sensitive to gluon at x~0.01-0.1 through BGF process S.Ch ekanov, DESY PRC review (Oct 2004) 13 ZEUZEUSS jjeetsts QQCCDD aannaalyslysisis ZEUS only fit ZEUS + JETS fits
Improvement in determination of gluon densities at mid-to-high x Rigorous treatment of uncertainties
S.Chekanov, DESY PRC review (Oct 2004) 14 DDISIS aatt HHERERAII:AII: ccoollisllisioionnss wwithith ppoolalarrizizeedd lelepptotonnss
NC DIS: CC DIS: Z0 couples differently to the left and right Linear dependence on polarization handed lepton Contribution to all Q2 Contribution at high Q2 ± (P) = (1± P) ± (0) (dependence of electroweak terms in the CC CC cross section) HERA II data: 16.4 pb-1 with P= -40.2% 14.1 pb-1 with P= 31.8% S.Chekanov, DESY PRC review (Oct 2004) 15 RReessuullttss oonn ppoollaarrizizaatiotionn.. HHEERRAAIIII ddaatata
NC DIS
CC DIS
Polarization effect established in CC DIS More data are needed for NC DIS
Agreement with the SM for both CC & NC DIS
S.Chekanov, DESY PRC review (Oct 2004) 16
ααs(M(MZ)) detdetermermiinatnatiionon
Most precise measurement from inclusive jets
Most recent measurement Competitive results from 3/2 jet ratio Theoretical uncertainties dominate Influence on world average
S.Chekanov, DESY PRC review (Oct 2004) 17 RRunningunning ααs
• Covers significant range in energy scale
• Running of αs in single experiment • Theoretical uncertainties dominate - NNLO QCD is needed
S.Chekanov, DESY PRC review (Oct 2004) 18 CChhaarrmm pprroodduucctiotionn
Charm production directly sensitive to gluon density in proton Look at “golden” decay channel: D* ® D0 ® K
Low Q2 with BPC
Increase of statistics for heavy-flavor analyses relies on : - extending the track acceptance to lower Agreement with NLO QCD for angles (MVD/STT) four decades in Q2 - tagging with MVD
S.Chekanov, DESY PRC review (Oct 2004) 19 CChhaarrmm sstutuddieiess uussiningg HHERERAA IIII ddaatata
Charm tagging using decay length Use MVD detector
Decay length significance Sl=l/σl
First look at HERA II data shows that lifetime tagging with MVD works as expected Large potential for the future
S.Chekanov, DESY PRC review (Oct 2004) 20 BeautBeautyy productproductiionon
Driviven by gluons QCD calculationsions: – γp: FMNR (Frixiione et all.) – DIS: HVQDIS (Harriis, Smith) Mulltii-scalle problem
- mb ~ 5 GeV hard scale ensures reliable QCD calculations - Q2 (DIS) b - PT (PHP, DIS)
Data somewhat above massive NLO QCD
S.Chekanov, DESY PRC review (Oct 2004) 21 BeBeaauutyty sstutuddieiess uussiningg HHERERAA IIII ddaatata
rel • large mass leads to large pt of μ relative to jet axis • large B-lifetime: use μ impact parameter δ from MVD
rel A beauty fraction 16.1 ± 2.7% extracted using pt method Gives consistent result with the impact-parameter method Large potential for the future
S.Chekanov, DESY PRC review (Oct 2004) 22 InclusivInclusivee diffractiondiffraction wwithith LPLPSS andand charmcharm datadata
Proton-taggiing method wiith LPS
– xL> 0.9
– xIP < 0.06
– high Mx accessiblle (up to 40 GeV!)
NLO QCD fiits iinclude LPS & charm data
• Good description by the NLO QCD fit • Fraction of t-channel momentum carried by gluons ~82% at initial scale (Q2=2 GeV2)
S.Chekanov, DESY PRC review (Oct 2004) 23 DDiffractiviffractivee dijetdijet photoproductionphotoproduction R=1 R=0.34 QCD factorizatiion:
centrall probllem of hard diiffractiion Does not holld iin pp CDF measurement iis by factor 10 llower than NLO based on H1 diiffractiive PDF
need a suppression factor resollved contributiion iin diiffractiive photoproductiion may requiire a simillar correctiion (factorizatiion breaking?) LRG 3<η<5 ( FPC region) Comparisons with M.Klasen & G.Kramer
• 30-fold increase in luminosity compared to previous ZEUS analysis • Global suppression is more likely than a resolved photon suppression (see shapes)
S.Chekanov, DESY PRC review (Oct 2004) 24 DDiiffffractractiionon iinn CCCC DDIISS
Diffractive events - significant component of NC DIS What about CC DIS - e+p→νW+→νX?
2 2 For Q >200 GeV ηmax<2.9, xIP<0.05: using 99-00 data:
9 events with LRG σ = 0.49 ± 0.2 (stat) ± 0.8 (sys.) pb agrees with RAPGAP CC (color singlet exchange between W+ and proton)
S.Chekanov, DESY PRC review (Oct 2004) 25 PentPentaquarksaquarks renaisissance ofof hadron specttroscopy?
Constituent Quark model: mesons q q baryons q qq
Does not predict more complicated states (but can accommodate them)
A number of fixed-target experiments observed a narrow baryonic state at 1530 MeV consistent with pentaquark predictions (Diakonov, Petrov, Polyakov)
First evidence of θ+: • in HEP colliding experiment • for antipentaquark
S.Chekanov, DESY PRC review (Oct 2004) 26 ZZEUEUSS mmeasuremeasurementent ofof θθ+ summary of θ+ measurements
(ep ® e + X ® eK 0 pX ) = 4.2 ± 0.9(stat)+1.2 (syst)% (ep ® eLX ) -0.9
• One of the most precise measurements • Significant impact on the world average m=1530 ±2 MeV • First cross sections in DIS
S.Chekanov, DESY PRC review (Oct 2004) 27 SearchSearch fforor heavheavyy ststrangerange pentpentaquarksaquarks
— 0 NA49 observes Ξ 3/2 and Ξ 3/2 pentaquark states wiith mass 1862 MeV
NA49
Clean PDG Ξ0(1530) signall ZEUS does not observe the signal reported by NA49
S.Chekanov, DESY PRC review (Oct 2004) 28 SearchSearch fforor charmcharm pentpentaquarksaquarks + 0 If = u u dd s exists, then c = uu dd c can also exist H1 reported a narrow signal at 3099 MeV (Phys. Lett. B588 (2004) 17)
r H1 reports in their measured kinematic
region (DIS): mme
su * *
s s R = N( ® D p / D ) »1%
i c h
t (consistent with photoproduction data)
m m
ro
f
r r e
p ZEUS excludes this fraction using larger
a *
p D data sample:
l
a n
i - at 9 σ in DIS and photoproduction f - at 5 σ in DIS (Q2>1 GeV2)
ZEUS data is in contradiction with H1 report
S.Chekanov, DESY PRC review (Oct 2004) 29 ManyMany newnew resulresulttss fforor IICCHHEP04EP04
BFKL studies Azimuthal asymmetry Event shapes Color dynamics Multiplicity measurements A search for stop production
S.Chekanov, DESY PRC review (Oct 2004) 30 SumSummmaryary
Significant improvement in ZEUS data taking efficiency
Data taken using new detectors:
MVD & STT
GTT at second-level trigger
ZEUS detector is in good shape. STT problem is under investigation
Only small fraction of results made public since May 2004 were shown
HERA II data are presented at ICHEP04
Looking forward to more data
S.Chekanov, DESY PRC review (Oct 2004) 31