status of zeus rainer mankel desy hamburg --for the zeus collaboration-- prc public session...

Status of ZEUSStatus of ZEUS

Rainer MankelRainer MankelDESY HamburgDESY Hamburg

--for the ZEUS collaboration----for the ZEUS collaboration--

PRC Public Session 26-May-PRC Public Session 26-May-20052005

26-May-2005 R. Mankel: Status of ZEUS 2

OutlineOutline

Data-taking & detector statusData-taking & detector status Data processing & simulationData processing & simulation Physics highlightsPhysics highlights

heavy flavoursheavy flavours QCD fits & QCD fits & ss determination determination diffractive final statesdiffractive final states


HERA-II LuminosityHERA-II Luminosity

HERA-II finally at cruising speedHERA-II finally at cruising speed almost reached integrated luminosity of HERA-Ialmost reached integrated luminosity of HERA-I Instantaneous luminosity in eInstantaneous luminosity in e––p running surpassed ep running surpassed e++p p


ZEUS Data-TakingZEUS Data-Taking

0 200 400 600 800 1000 1200 1400

04.05.2005

06.05.2005

08.05.2005

10.05.2005

12.05.2005

14.05.2005

16.05.2005

ZEUS Gated Luminosity per day (with "HV on")

Series of daily gated Series of daily gated luminosity records luminosity records ((1.2 pb1.2 pb-1-1))

Remarkable Remarkable improvement in improvement in ZEUS data-taking ZEUS data-taking efficiencyefficiency in general above in general above

80%80% MVD on 95% of timeMVD on 95% of time

62 pb62 pb-1-1 of new e of new e––p p data on tapedata on tape

ZEUS Run Efficiency [%]

0102030405060708090

100

[nb-1]


Detector StatusDetector Status Calorimeter: stable Calorimeter: stable

with low number of with low number of bad channelsbad channels

MVD: signal & noise MVD: signal & noise are stableare stable

CTD: low trip rate. CTD: low trip rate. No signs of No signs of premature ageing premature ageing

Increased use of Increased use of Global Track Trigger Global Track Trigger at global SLT levelat global SLT level

Detector is in Detector is in good shapegood shape

Efficiency Efficiency improvements:improvements: comprehensive comprehensive

monitoring via web monitoring via web statistics pagesstatistics pages

pre-luminosity test trigger pre-luminosity test trigger runsruns

complete rebuild of TLT complete rebuild of TLT farm hardware & softwarefarm hardware & software


Straw Tube Tracker (STT)Straw Tube Tracker (STT)

STT presently off because STT presently off because of insufficient cooling, of insufficient cooling, which otherwise which otherwise interferes with stable interferes with stable operation of solenoidoperation of solenoid

Preparing repair that does Preparing repair that does not break beam vacuumnot break beam vacuum additional cooling & additional cooling &

insulation insulation Decision within next Decision within next

weeksweeks

FDET/STTadd insulation

& cooling

GO magnet


Data ProcessingData Processing

Central reconstruction & Central reconstruction & analysis facility for ZEUSanalysis facility for ZEUS

Presently farm of 150 Presently farm of 150 Intel Xeon processors Intel Xeon processors

>600 000 analysis batch >600 000 analysis batch jobsjobs in one year in one year Up to 22000 jobs per Up to 22000 jobs per

weekweek Average data Average data

throughput throughput 10 TB/day10 TB/day


ZEUS Reconstruction ZEUS Reconstruction PerformancePerformance

Daily production (#events) during Daily production (#events) during reprocessing of 2004 ereprocessing of 2004 e++ data: data:

17-Oct 9-NovDate

1 M

2 M

3 M

Events reconstructed per day

Peak production: Peak production: 3 M events/day3 M events/day at HERA-I times, at HERA-I times,

peak rate was peak rate was 500 k 500 k events/dayevents/day

reconstruction of reconstruction of HERA-II events is HERA-II events is 6x more CPU-6x more CPU-intensive than intensive than with HERA-I with HERA-I

Sizable Sizable increase in increase in processing processing performanceperformance

Fast turnaroundFast turnaround

3 M events/day


HERA-II MC ProductionHERA-II MC Production Assessment of Monte Assessment of Monte

Carlo simulation needs Carlo simulation needs in 2003 revealed in 2003 revealed opening of a huge gapopening of a huge gap

Reasons: Reasons: HERA-II luminosity HERA-II luminosity additional demand additional demand

from new detector from new detector componentscomponents

considerable considerable increase in increase in simulation demandsimulation demand during HERA-IIduring HERA-II

Solution: Computing Solution: Computing Grid TechnologyGrid Technology

Gap


Solution: ZEUS GridSolution: ZEUS Grid

UI

RLS

dCacheMSS

SERB

WNWNWNWN CE

SE

WNWNWNWNCE

DESY

Zeus Integrated MC Production System

Padova

Tel Aviv

Rutherford

KEK

Classical funnel

sitesGRID GRID GATEWAYGATEWAY

Built on top of Built on top of LHC LHC Computing GridComputing Grid software software

Transparent Transparent integrationintegration of traditional funnel sites of traditional funnel sites and grid sitesand grid sites

ReuseReuse of existing ZEUS- of existing ZEUS-specific middlewarespecific middleware

““ZEUS Grid Toolkit”ZEUS Grid Toolkit” Brings the Brings the grid to the grid to the

end user end user

SE

WNWNWNWNCE


ZEUS Grid-Based MC Production ZEUS Grid-Based MC Production TotalsTotals

more than 200 more than 200 million events million events producedproduced

29 grid sites29 grid sites in 7 in 7 countries on 2 countries on 2 continents continents

>60% of MC >60% of MC produced on gridproduced on grid

by time of last by time of last PRC: 600,000 PRC: 600,000 eventsevents

first first non-LCG2non-LCG2 site: site: Univ. Wisconsin Univ. Wisconsin (joined last month)(joined last month)


Grid: ZEUS & Other Grid: ZEUS & Other ExperimentsExperiments In January, In January,

ZEUS ZEUS production production amounted to amounted to 16% of total 16% of total CPU powerCPU power in in all UK grid sitesall UK grid sites running at very running at very

low priority low priority (“opportunistic (“opportunistic mode”)mode”)

LHCBLHCBZEUSZEUS

ATLASATLAS


Physics HighlightsPhysics Highlights

Many essential results still coming Many essential results still coming from HERA-I datafrom HERA-I data 8 papers published since last PRC8 papers published since last PRC

HERA-II data are under analysisHERA-II data are under analysis still still less statisticsless statistics than HERA-I, but than HERA-I, but

increasingincreasing also first results from fresh ealso first results from fresh e–– data data


First Impact of New eFirst Impact of New ep Data: p Data: D*D*

About equal sample About equal sample sizes of esizes of e++ and e and e data in HERA-IIdata in HERA-II

Already 2x as much Already 2x as much integrated eintegrated ep p luminosity luminosity compared to HERA-Icompared to HERA-I

Time to revisit an Time to revisit an old puzzleold puzzle……

D*+ D0+ (K+)+

e+p

e-p

40 pb-1

33 pb-1

m(D0+) m(D0)


D* in New Data (cont’d)D* in New Data (cont’d) There is There is no obvious no obvious

mechanismmechanism that should that should lead to different D* lead to different D* cross sections for ecross sections for ep p and eand ep scatteringp scattering

Still, an indication of Still, an indication of such an asymmetry such an asymmetry was was seenseen in the HERA-I data in the HERA-I data r(er(ep)/ r(ep)/ r(ep)=1.67p)=1.670.21 0.21

(Q(Q22>40 GeV>40 GeV22)) statistical fluctuation, or statistical fluctuation, or

mysterious anomaly?mysterious anomaly?

Charm production by boson-gluon fusion


D* in New Data (cont’d)D* in New Data (cont’d)

HERA-II data with increased eHERA-II data with increased ep statistics p statistics do not show this anomalydo not show this anomaly any more any more


Total bb Cross SectionTotal bb Cross Section Traditional analysis tags Traditional analysis tags

single B hadrons (e.g. with single B hadrons (e.g. with )) example: pexample: ptt

relrel study study sensitive to fast B hadronssensitive to fast B hadrons strong cuts into phase strong cuts into phase

space to suppress space to suppress backgroundbackground

Tagging of Tagging of bothboth B’s B’s makes use of the correlationmakes use of the correlation allows low pallows low ptt

μμ thresholds thresholds is sensitive to B hadrons is sensitive to B hadrons

that are that are practically at restpractically at rest measures total bb cross measures total bb cross

sectionsection

double tag

HERA-I DataHERA-I Data


Di-Muons: Data vs MCDi-Muons: Data vs MC

Good overall description with MCGood overall description with MC bb contribution ~2000 events, purity ~43%bb contribution ~2000 events, purity ~43%

Same-charge Same-charge combinations combinations used to used to normalize light-normalize light-flavor flavor backgroundbackground

non-isolated, ET>8 GeV


bb Cross Section from Di-Muon Events bb Cross Section from Di-Muon Events (cont’d)(cont’d)

NLO QCD predictions:NLO QCD predictions:PHP: 5.8 nb PHP: 5.8 nb

(FMNR,CTEQ5M)(FMNR,CTEQ5M)DIS: 1.0 nb DIS: 1.0 nb

(HVQDIS,CTEQ5F4)(HVQDIS,CTEQ5F4)

6.8 nb6.8 nb

NLO prediction lower NLO prediction lower than the datathan the data

applied first time at applied first time at HERAHERA

nbsyststatGeVsXbbeptot )(8.43.5)(8.11.16)318)((

+3.0+3.0

––1.71.7

this analysis

D*μ PHP

D*μ DIS


ss Determination Determination From NLO QCD FitsFrom NLO QCD Fits

Recently, parton distribution Recently, parton distribution functions have been functions have been obtained by a rigorous fit to obtained by a rigorous fit to combined inclusive DIS & jetcombined inclusive DIS & jet datadata uncertainty of the mid-to-high uncertainty of the mid-to-high

x gluon distribution in inclusive x gluon distribution in inclusive DIS is DIS is very effectively very effectively constrainedconstrained by the jet cross by the jet cross sectionssections

sufficient sensitivity to sufficient sensitivity to determine PDFs determine PDFs entirely in one entirely in one experimentexperiment

Gluon distribution: relative uncertainty in bins of Q2

1010


ss Determination From NLO Determination From NLO QCD Fits (cont’d)QCD Fits (cont’d)

This method can also be This method can also be used to determine used to determine ss(M(MZZ) ) as a free parameter in as a free parameter in the fitthe fit

ss(M(MZZ) = 0.1183) = 0.1183 0.0028 (exp.) 0.0028 (exp.) 0.0008 (model) 0.0008 (model) 0.0050 (th.) 0.0050 (th.)

in agreement with world in agreement with world averageaverage ss(M(MZZ)=0.1182 )=0.1182 0.0027 0.0027

first first precise determination precise determination of of ss from HERA data alone from HERA data alone

world average(Bethke 2004):


Strong Coupling ConstantStrong Coupling Constant

Comprehensive average Comprehensive average of of ss(M(MZZ) measurements ) measurements at HERAat HERA conservative conservative

assumptions on assumptions on correlations of theoretical correlations of theoretical uncertainties (higher uncertainties (higher order, PDFs, order, PDFs, hadronisation)hadronisation)

ss(M(MZZ)=0.1186)=0.11860.0011 0.0011 (exp)(exp)0.0050 (th)0.0050 (th)

experimental uncertainty experimental uncertainty ~0.9%, theoretical ~4%~0.9%, theoretical ~4%

Need for NNLO Need for NNLO calculationscalculations

C. Glasman, DIS2005


NC Cross Section at High xNC Cross Section at High x

High-x region is hard High-x region is hard to measureto measure for current jet at very for current jet at very

low angle, low angle, hadhad is is either badly resolved, either badly resolved, or the jet is not or the jet is not detected at alldetected at all

x range ends at 0.65x range ends at 0.65 limits determination limits determination

of PDF at large xof PDF at large x


NC Cross Section at High x NC Cross Section at High x (cont’d)(cont’d)

New approachNew approach beyond beyond classical “double classical “double angle method”:angle method”: use jet finder & use jet finder &

determine determine x from Ex from Ejetjet and and jetjet

x x E Ejetjet good good resolutionresolution

if no jet if no jet distinguishable, classify distinguishable, classify event into event into integrated integrated binbin (x (xmaxmax<x<1)<x<1)

One jet

Zero jet

e+

e+


NC at High x: Data vs. NC at High x: Data vs. TheoryTheory

Good Good agreement agreement with PDFswith PDFs

This method This method applied first applied first time at HERAtime at HERA

dxd2dxdQ2xmax

11 xmax


Rapidity Gaps at High QRapidity Gaps at High Q22

Interest in diffraction at high Interest in diffraction at high QQ22 extends far beyond HERA extends far beyond HERA clean final statesclean final states at LHC, e.g. at LHC, e.g.

for Higgs?for Higgs? Test factorization of Test factorization of

diffractive component of diffractive component of proton proton

At last PRC, first results for At last PRC, first results for charged currentscharged currents were were shownshown statistics did not allow to statistics did not allow to

measure Qmeasure Q22 dependence dependence

Large rapidity

gap

Look for rapidity gaps in Look for rapidity gaps in neutral current eventsneutral current events

Compare with charged Compare with charged current analysiscurrent analysis


Rapidity Gaps in NC Rapidity Gaps in NC EventsEvents

Forward Plug Calorimeter

(FPC)

Rap

idit

y ga

p

““Normal” DIS MC (Ariadne) Normal” DIS MC (Ariadne) clearly clearly insufficientinsufficient at low at low maxmax

Need Ariadne+RAPGAP Need Ariadne+RAPGAP (diffractive MC) to describe the (diffractive MC) to describe the datadata

with FPC veto (at beam pipe)

55


Rapidity Gaps in NC: QRapidity Gaps in NC: Q22 DependenceDependence

SizableSizable diffractive contribution diffractive contribution to NC cross sectionto NC cross section drops with rising Qdrops with rising Q22

still 2% at Qstill 2% at Q22=1500 GeV=1500 GeV22

NC and CC NC and CC compatiblecompatible

For comparison:

Low-Q2 Data

High -Q2 NC

x P<0.05


Exclusive Electroproduction Exclusive Electroproduction of Vector Mesons (new: of Vector Mesons (new: ))

Very clean final state, Very clean final state, large kinematical rangelarge kinematical range

At HERA, observe At HERA, observe transition from soft to hardtransition from soft to hard regimeregime

Present set of Present set of measurements: measurements: , , (new), (new), J/J/

Differential cross sections show Differential cross sections show high sensitivity high sensitivity to the gluon densityto the gluon density functions functions challenge to understand diffractive scattering challenge to understand diffractive scattering

quantitativelyquantitatively


Electroproduction: SignatureElectroproduction: Signature

scattered electron

K+K–

Reconstructed Reconstructed electron + 2 electron + 2 charged trackscharged tracks

Otherwise Otherwise detector detector completely completely emptyempty Scattered Scattered

proton escapes proton escapes near beam linenear beam line

3642 3642 signal signal eventsevents


VM Electroproduction: W VM Electroproduction: W DependenceDependence

Highly sensitive not Highly sensitive not only to different only to different models, but also to models, but also to differentdifferent gluon gluon densities within the densities within the samesame model model

J/


Electroproduction: QElectroproduction: Q22 DependenceDependence

Clean Clean separation of separation of LL and and TT components components challenges modelschallenges models good qualitative good qualitative

description, in particular description, in particular TT

better overall better overall agreement with FS04 agreement with FS04 modelmodel

Excellent sector for Excellent sector for further optimizations further optimizations of pQCD calculationsof pQCD calculations


SummarySummary Encouraging data rates from HERA-IIEncouraging data rates from HERA-II Detector & data chain in good shapeDetector & data chain in good shape MC mass production on computing gridMC mass production on computing grid Wealth of new physics resultsWealth of new physics results Looking forward to a Looking forward to a

fruitful data-taking period fruitful data-taking period with a huge data sample with a huge data sample & post-upgrade detector & post-upgrade detector and polarizationand polarization


The EndThe End


Backup SlidesBackup Slides


More Pieces to Pentaquark More Pieces to Pentaquark PuzzlePuzzle(1520) : both in forward & backward hemisphere

+: only in forward hemisphere + signal signal mainly mainly

from forwardfrom forward pseudo rapidity pseudo rapidity regionregion unlike regular unlike regular

baryons baryons (1520) and c

predominantly at medium Q2

similar to c

no sign of decuplet partners seen in –– and –+ ( NA49)


Di-Muon Mass Spectra (Data vs Di-Muon Mass Spectra (Data vs MC)MC)

low mass

low mass high mass

high mass

same B

(charm cascade)

+ J/

different B’s (signal!)

+ cc + light flavor BG

mainly light flavor BG

different B’s

(charm cascade + BB mixing)

+ light flavor BG

Good description with MCGood description with MC bb contribution ~2000 eventsbb contribution ~2000 events


bb Cross Section: a Di-Muon bb Cross Section: a Di-Muon EventEvent


bb from Di-Muons: Normalization bb from Di-Muons: Normalization of BG-MCof BG-MC

cc: normalize to D*mu analysiscc: normalize to D*mu analysis Bethe-Heitler, elastic charmonium: Bethe-Heitler, elastic charmonium:

normalize to data under isolation normalize to data under isolation cutcut

Light flavor: use like sign spectrum Light flavor: use like sign spectrum (minus bb MC)(minus bb MC)


NC Cross Section at High x NC Cross Section at High x (cont’d)(cont’d)

Considerable Considerable extension of extension of kinematical region kinematical region towards high x, in towards high x, in particular for particular for moderate Qmoderate Q22 (zero jet (zero jet case)case)

Improved x resolution Improved x resolution (one jet case)(one jet case)

Only 99-00 eOnly 99-00 e++ data data used so far (65 pbused so far (65 pb-1-1))


Electroproduction: W Electroproduction: W SpectrumSpectrum

~W~W

Test scaling Test scaling of of with with (Q(Q22+M+MVV

22))

J/J/ is always hard is always hard hardness increases with Qhardness increases with Q22

shows shows intermediate behaviorintermediate behavior


J/J/ Electroproduction Theory vs Electroproduction Theory vs ExpExp

shown by T. Teubner at DIS2005shown by T. Teubner at DIS2005

status of zeus rainer mankel desy hamburg --for the zeus collaboration-- prc public session...

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status of zeushera

status of zeussolution

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zeus production

integrated luminosity

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