wesley smith, u. wisconsin, august 22, 2006 doe review: task b: lepton hadron scattering - 1 task b:...

Wesley Smith, U. Wisconsin, August 22, 2006 DOE Review: Task B: Lepton Hadron Scattering - 1

Task B: Lepton-Hadron CollisionsTask B: Lepton-Hadron CollisionsTask B: Lepton-Hadron CollisionsTask B: Lepton-Hadron Collisions

Graduate students(resident at DESY)

Eric BrownsonTom DanielsonHomer WolfeAdam EverettMichele RosinPat Ryan

Don Reeder

Wesley SmithProfessors

ZEUS editorial board, Trigger convenor, Former AmZeus chair

former AmZeus chair, retiring

Graduated - Purdue - CMSGraduated - Weizmann - ZeusGraduated - Michigan State - ATLAS

Assistant Scientist(resident at DESY)

A. Savin

D. Kçira

Hadronic Final States Physics coord.Calorimeter Trigger coord.

Electronics Engineer(resident in Madison)

M. Jaworski Trigger electronics maintenance

Trigger operationsPhysics Analysis

Left for Louvain - CMS


UW DESY Group OrganizationUW DESY Group Organization1993 - 20051993 - 2005

UW DESY Group OrganizationUW DESY Group Organization1993 - 20051993 - 2005

Beginning Students (2)• Learning • Cal.Trigger shifts• on call 24x7

Intermediate Students(2)• Resp. for Cal Trig shifts• Begin physics analysis

Senior Students(2)• Released for Thesisanalysis

• Consultation,assistance, shifts

Supervision• Local Scientists - A. Savin & D. Kcira• Visits by D. Reeder & W. Smith• Weekly video meetings (DESY- UW)

Now: 3 students & 1 scientist Now: 3 students & 1 scientist redirect effort to CMS (lost!) redirect effort to CMS (lost!)

“The TEAM!” July ‘05

PurdueCMS

WeizmannZEUS

LouvainCMS

MSUATLAS


Uranium-ScintillatorBarrel Calorimeter doneby UW & US group

First Level trigger for entire calorimeter built & maintained by UW group

Toroidal Iron Magnet designed by UW & coils built by UW

Since 1993

Wisconsin ContributionsWisconsin ContributionsWisconsin ContributionsWisconsin Contributions

Contributions include supporting M&O• Major task for trigger system

Obligation to exploit investment• Cost effective access to a rich lode of physics


Beam PipeMagnets

Straw TubeForward Tracker

Argonne built electronics

Micro VertexDetector

Lumi detector upgrades

MVDSTT

+ beam counters, tagger

ZEUS HERA-II UpgradesZEUS HERA-II UpgradesZEUS HERA-II UpgradesZEUS HERA-II Upgrades

Major investment by DESY and ZEUS collaborators


HERA - IIHERA - IIHERA - IIHERA - II

DESY Investment pays off (> 70 new magnets)Switch to electrons fall 2004HERA-I ZEUS total positron/ electron - proton luminosity of 115 pb-1/17pb-1. Electron-positron collisions ended June 2006

• Electron sample = 214 pb-1.

Switching to positrons for year of final running

• Positron sample ~ 400 pb-1.

Increase over HERA-I program of a factor of 4 in statistics (and more than an order of magnitude in electron statistics)Final run at lower energy

• Measure FLgluon for LHC


ZEUS Physics PublicationsZEUS Physics Publications2005-20062005-2006

ZEUS Physics PublicationsZEUS Physics Publications2005-20062005-2006

Since January 2005, submitted 12 papers to refereed journals• 10 have already been published, 2 more accepted for publication

More than 160 articles in refereed journals• 30 physics publications with > 100 citations each.

4 Journal Articles from UW Group published/accepted:1. I.P.Ivanov, N.N.Nikolaev, A.A.Savin (UW Scientist), “Diffractive vector meson production at HERA: from soft to hard QCD”, Phys. Element. Part. Atom. Nucl. vol.36 (2006) 1. -- 178 page review of HERA diffraction

2. S. Chekanov et al., “Forward Jet Production in Deep Inelastic ep Scattering and low-x Parton Dynamics at HERA”, Phys. Lett. B632 (2006) 13-26 . -- S. Lammers thesis.

3. S. Chekanov et al., “Multijet Production in Neutral Current Deep Inelastic Scattering at HERA and Determination of s, Euro. Jour. Phys. C44 (2005) 183-193 -- L. Li thesis.

4. S. Chekanov et al., “Event shapes in DIS at HERA”, DESY-06-042, accepted by Nuclear Physics B. -- A. Everett thesis


Wisconsin Zeus talksWisconsin Zeus talksin 2005, 2006 (through June) - 10 Talksin 2005, 2006 (through June) - 10 TalksWisconsin Zeus talksWisconsin Zeus talksin 2005, 2006 (through June) - 10 Talksin 2005, 2006 (through June) - 10 Talks

1. D. Kcira, Jet production at HERA and the measurement of s, 18th Lake Louise Winter Institute 2005 on Fundamental Interactions, Alberta, Canada, February 2005

2. A. Savin, Jets at HERA and determination of s, 40th Rencontres de Moriond on QCD, La Thuile, Italy, March 2005

3. A. Everett, Event Shapes, 13th International Workshop on Deep Inelastic Scattering (DIS ’05), Madison, USA, April 2005.

4. M. Rosin, Charged multiplicity distributions, 13th International Workshop on Deep Inelastic Scattering (DIS ’05), Madison, USA, April 2005.

5. P. Ryan, Forward jet production at HERA, 2005 Europhysics Conference, Lisbon, Portugal, July 2005.

6. A.Savin. Event shapes in DIS at ZEUS ,DIS06, Tsukuba, Japan, April 2006

7. A.Savin K0 and Lambda production at ZEUS , DIS06, Tsukuba, Japan, April 2006

8. P.Ryan, Photoproduction of events with rapidity gaps between jets at ZEUS DIS06, Tsukuba, Japan, April 2006

9. E.Brownson Prompt-photon plus jet production at ZEUS DIS06, Tsukuba, Japan, April 2006

10. P.Ryan Photoproduction of events with rapidity gaps between jets at ZEUS HERA-LHC workshop, CERN, June 2006.


ep: large asymmetry btw. beams•Most of hadronic final state produced near proton and outside acceptance of detector

Method•Use invariant mass for comparing to e+e-, pp

•Provide clear separation from leading particle(s) using final state particles from

• The current region of Breit frame

• The photon region of the Hadronic Center of Mass (HCM) frame

Breit Frame definition: 2xp + q = 0

Current region of Breit Frame analogous to one hemisphere of e+e-.

ee++ee--/ep multiplicity: Breit Frame/ep multiplicity: Breit Frameee++ee--/ep multiplicity: Breit Frame/ep multiplicity: Breit Frame

DIS event

La

b F

ram

eB

reit

Fra

me

Bre

it F

ram

e

PT

PL


ep multiplicity vs. other exp’tsep multiplicity vs. other exp’tsep multiplicity vs. other exp’tsep multiplicity vs. other exp’ts2<nch> in current and photon regions compared to e+e-, pp & previous ZEUS measurements

ZEUS ep results agree with e+e-, pp at both low and high values of energy

At low energy agreement better than previous ZEUS result vs Q

MC predictions from both frames agree with ZEUS measurements

Thesis research of graduated UW PhD student Michele Rosin, presented at DIS ‘05, ZEUS journal article in Editorial Board.


Particle and Energy FlowParticle and Energy FlowParticle and Energy FlowParticle and Energy Flow

∑∑ ⋅

=i i

i i

p

npT r

rˆ

Thrust

∑∑ ×

=i i

i i

p

npB r

rˆ

Broadening

( )( )2

2

2

sin3

∑∑

=i i

ij ijji

p

ppC r

rrθ

C Parameter

( )( )2

2

2

2ii

i i

E

pM

∑∑

=μ

Jet Mass

Combination of the hard and soft scales

Sums are over all momenta in the current hemisphere of the Breit frame

Axis Dependent: TT, BT, T, B

Axis Independent: C, M2

TT axis

TM axis

T axis

Tm axis

*


Event Shape ParametersEvent Shape ParametersEvent Shape ParametersEvent Shape Parameters

Extracted parameters for each shape

•Fitted s values consistent to within 5%

•Fitted 00.45 to within 10%

•(excluding T)

Theory errors dominate, except for axis shapesGraduated UW PhD student Adam Everett’s thesis, presented at DIS’05 & accepted for publication by Nuclear Physics B. World Average


Parton Energy and Parton Energy and kkTT Ordering OrderingParton Energy and Parton Energy and kkTT Ordering Ordering•Study Differences in summing QCD terms in parton evolution•DGLAP: ordering in both kT and x

•BFKL: not ordered in kT but ordered in x

•Potential differences• DGLAP: Jets strongly correlated in

Energy, azimuthal and polar angles• BFKL: Jets not necessarily strongly

correlated• Expect more energetic jets in forward

region with BFKL than with DGLAP

1,2,2,1,, ... ttntntnt kkkkk >>>>> −−

121 ... xxxx nn >>>> −

121 ... xxxx nn >>>> −


Dijet Trijet

ZEUS Multijet MeasurementsZEUS Multijet MeasurementsZEUS Multijet MeasurementsZEUS Multijet Measurements

ZEUS inclusive dijet and trijet measurements well understood and modeled

• Multijet cross sections vs. NLO calculations

• Graduated UW PhD student Liang Li’s Thesis, Eur. Jour. Phys. C44 (2005) 183-193

• DGLAP NLO dijet and trijet calculations describe data well in general

• Examine if agreement extends to “BFKL” kinematic regions


NLO vs. ZEUS Inclusive JetsNLO vs. ZEUS Inclusive JetsNLO vs. ZEUS Inclusive JetsNLO vs. ZEUS Inclusive Jets

Inclusive jet cross sectionvs. DISENT NLO calculation)

Graduated UW PhD student Sabine Lammers’ thesis, Phys. Lett. B632 (2006) 13-26

Low xBj disagreement btw. data & DISENT

Disagreement evident whenjet required•Structure Function analysesdo not require jets

•Further explore this region requiring more than one jet


Probing NLO QCD DGLAP:Probing NLO QCD DGLAP:Dijets at Low-Dijets at Low-xx

Probing NLO QCD DGLAP:Probing NLO QCD DGLAP:Dijets at Low-Dijets at Low-xx

Jets not strongly correlated in energy and azimuthal angle indicate BFKL effects•DGLAP: Jets strongly correlated in ET, angles

•“Back to back” in

Find that dijet production with low azimuthal separation are reproduced by pQCD DGLAP•Provided that higher order terms (O(s

3)) are included -- important at low-x.

Thesis research of UW PhD student Tom Danielson, presented at ICHEP06


Color Non-Singlet and Singlet Color Non-Singlet and Singlet Exchange in PhotoproductionExchange in PhotoproductionColor Non-Singlet and Singlet Color Non-Singlet and Singlet Exchange in PhotoproductionExchange in Photoproduction

Color Non-Singlet Exchange:•Final state partons color connected•Space between final state partonsfilled with final state particles • No Gap between jets

Color Singlet Exchange:•Final state partons not color connected•Space btw final state partons empty

• Rapidity Gap between jets--measure ETGap

Color Non-Singlet Exchange Color Singlet Exchange

Jet

Jet Jet

Jet

gap

proton remnantjet 1

jet 2

Resolved Resolved

ETGap


Evidence for Color SingletEvidence for Color SingletEvidence for Color SingletEvidence for Color Singlet

Inclusive dijet gap cross section as a function of ET

Gap vs. Herwig (x 3.3) and Pythia (x 1.8) with and without color-singlet exchange. MCs without a color-singlet contribution do not describe data in two lowest ET

Gap bins.Amount of color-singlet needed to give best fit to data is ~ 3-4% of the total inclusive dijet gap cross section integrated from0 - 12 GeV in ET

Gap.Graduated UW PhD student Pat Ryan’s thesis,, presented at DIS ‘06, ZEUS journal article in Editorial Board.


Prompt Prompt + Jet Photoproduction: + Jet Photoproduction:study hard interactions directlystudy hard interactions directly

Prompt Prompt + Jet Photoproduction: + Jet Photoproduction:study hard interactions directlystudy hard interactions directly

Use new Barrel Calorimeter Presampler to tag prompt photons & higher statistics sample to improve measurement Find improved agreement after raising energy cut on prompt photons from 5 to 7 GeV

Find both kT-factorization & NLO QCD models agree well. Thesis research of UW PhD student Eric Brownson, presented at DIS06, ICHEP06 & submitted to Eur. Phys. J. C (DESY-06-125).


CC inclusive jets in eCC inclusive jets in e--ppCC inclusive jets in eCC inclusive jets in e--pp

Measure differential cross sections for jet production in high statistics (125 pb-1) polarized (1st time) & unpolarized electron-proton scattering

& xBj cross sections agree with leading log parton shower MCs, but Et

jet & Q2 are somewhat different.

Thesis research of UW PhD student Homer Wolfe, presented at ICHEP 06


XIIIth Workshop on Deep XIIIth Workshop on Deep Inelastic Scattering (DIS05)Inelastic Scattering (DIS05)XIIIth Workshop on Deep XIIIth Workshop on Deep

Inelastic Scattering (DIS05)Inelastic Scattering (DIS05)in Madison, Wisconsin, April 27 - May 1

271 Participants, 240 TalksWesley Smith, Chairman

Local Organizing Committee:

Sridhara Dasu, Tao Han, Aimee Lefkow, Don Reeder

U. Wisconsin

Jose Repond, Argonne


•A. Wagner:

"The calorimeter ….. readout and trigger have paved the way for the LHC and Tevatron II designs."

ZEUS TriggerZEUS TriggerZEUS TriggerZEUS Trigger

Design & Leadership by Wisconsin•W. Smith trigger co-convenor fromdesign until present (20 years)

•Challenge: interaction every 96 ns

•Beam-gas background > 100 kHz

•Revolutionary3-leveldeadtimelessdesign


Calorimeter First Level Trigger: Calorimeter First Level Trigger: ChallengesChallenges

Calorimeter First Level Trigger: Calorimeter First Level Trigger: ChallengesChallenges

Input requirements• Beam crossing every 96 nsec

• Background rate <100 kHz

• Max Level 1 Rate < 0.5 kHz

Processing requirements• 5 msec trigger decision time

• Data from 13K Phototubes

• Dynamic range of 4096:1

Trigger Functions at Level-1• Unique to Zeus trigger until LHC

• Identify e, .

• Sum energy, missing & total Et

• Pattern logic to compensatefor non-projective geometry:


Calorimeter First Level Trigger: Calorimeter First Level Trigger: Front EndFront End

Calorimeter First Level Trigger: Calorimeter First Level Trigger: Front EndFront End

270 Trigger Encoder Cards digitize to 12-bits, test for em v. had., quiet(m) & total energies.

720 Trigger Sum Cards collect signals & transmit every 96 ns to TEC's in Electronics House

140 Fanout Cards control TSC's


CAL FLT LogicCAL FLT LogicCAL FLT LogicCAL FLT Logic

Adder Cards find isolated e's & m's, and sum energies

2 double-board Adder Cards per crate receive & process data from 14 TEC's at 80 MHz

16 crates report to Global Cal Trigger


ZEUS First Level TriggerZEUS First Level TriggerZEUS First Level TriggerZEUS First Level TriggerContinues superb performance as luminosity increases

Example of Recent HERA Good Run: • High specific lumi. 2.3 x 1031

• Max lumi. to be expected: 5 ~ 6 x1031

• Deadtime less than 1%• Expect always < 5%

Keys to success:• Flexibility & Programmability

• Trigger studies by UW group to make changes

Low Lumi High Lumi


Trigger StudiesTrigger StudiesTrigger StudiesTrigger Studies

Adapt trigger to changing beam conditions • Study new configurations

• Switch to positrons this summer

• Switch to low energy running at end of year to measure FL

• Make test runs, study Monte Carlo & data

Understand trigger impact on physics analysis• Demand for increased detail on analysis of trigger

performance as preparing for precision measurements during low energy running.

• Regional and even tower by tower analyses of efficiencies for various triggers.


CriticalityCriticalityCriticalityCriticality

Unique - Invaluable• Zeus can function without many components but not

without the calorimeter and trigger.

• Efficiency and performance can be excellent ….. but it requires close monitoring and precise knowledge (it is aging!)

We have maintained and operated it to date and we have the tools, but …. it continues to need vigilant constant attention by an active, experienced staff at DESY.


Expertise at DESYExpertise at DESYExpertise at DESYExpertise at DESY

Assistant Scientist - A. Savin•Calorimeter Trigger Coordinator

•Provides technical coordination

•Works with other detector leaders

•Physics Analysis

•Own analyses & supervises students

•Leadership @ DESY

•Increased burden with departure of D. Kcira


Jade Hall test facilityJade Hall test facilityJade Hall test facilityJade Hall test facilityCalorimeter module electronics test with full module infrastructureComplete test crate & interface to global cal. trigger for full-scale check

of counting house (rucksack) electronics


Technical SupportTechnical SupportTechnical SupportTechnical Support

Technician: Cathy Farrow (formerly UW)•AmZeus/DESY has now hired Cathy and given her predominant responsibility for maintenance of the calorimeter hardware

•BUT ….. she can spend some (small) time on CAL FLT

•Helps to maintain test facility, makes simple board repairs

Expert Engineer: Matt Jaworski•~ 5 trips/year for 2-3 weeks to make difficult repairs

•Frequency increasing due to aging electronics and to compensate for Cathy Farrow's reduced activity.

Designer (available for consultation)•Joe Lackey (retired) - not supported by grant.


OperationsOperationsOperationsOperations

Detector & Electronics House•Write, test & maintain electronics test programs•Maintain & update bad channel list

•< 1% channels w/any trigger problem (none dead) •Diagnose & repair electronics

•Experimental downtime due to CAL FLT < 1%•Daily checking programs•Maintain & operate Jade Hall Facility•24 hour/day support during running•Frequent calibration with charge injectors to set the time & energy.•Special cable-checking charge injection runs after any repairs

Software Operations•Run Control maintenance•Trigger data validation

•Online & Offline analysis of rates & efficiencies•Monte Carlo & data trigger simulation maintenance


Online & offline DiagnosticsOnline & offline DiagnosticsOnline & offline DiagnosticsOnline & offline Diagnostics

Trigger bits vs.simulation of trigger using reconstructed data as input.

Each trigger efficiency curve is monitored & checked online.

Each trigger in every data run is analyzed offline to check efficiency and rise of threshold curve.


ConclusionsConclusionsConclusionsConclusionsUW is a leading group ZEUS operation & analysis•Doing great physics

• 10 International workshop/conference talks in 2005/6 so far• 4 publications

UW provides continuity & strength vital for ZEUS•ZEUS cannot operate without CAL FLT

Exciting physics amidst shrinking HEP opportunities•ZEUS runs until June 30, 2007

“Poster child” for an international role for US HEP• Model for future international collaborations (i.e. TESLA)

Producing top-notch physicists•Experience in sophisticated hardware & software•Physics analysis in close collaboration with theorists•16 Wisconsin ZEUS students received Ph.D.s thus far•3 More ZEUS students working on Ph.D.s:

• Danielson,Brownson, Wolfe:

wesley smith, u. wisconsin, august 22, 2006 doe review: task b: lepton hadron scattering - 1 task b:...

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