Ole Miss on DOle Miss on DØØ

Breese QuinnUniversity of Mississippi

DOE Review 2/13/06

B. Quinn University of Mississippi

2

Tevatron LuminosityTevatron Luminosity

~1.5 fb~1.5 fb--11

delivereddeliveredDoubled in the Doubled in the last yearlast year

Average peak close to Average peak close to 1.51.5××101032 32 cmcm--22ss--11

Almost achievedAlmost achieved 22××101032 32

cmcm--22ss--11

DOE Review 2/13/06

B. Quinn University of Mississippi

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DDØØ Recorded LuminosityRecorded LuminosityAveraging ~88% efficiencyAveraging ~88% efficiency

DOE Review 2/13/06

B. Quinn University of Mississippi

4

Top Results (Preliminary)Top Results (Preliminary)Single top production cross section (370 pb-1)

s channel 95% CL upper limit: 5.0 pbt channel 95% CL upper limit: 4.4 pb

Top massTemplate method (230 pb-1): Matrix method (320 pb-1):Ideogram method (160 pb-1):

W Helicity (230 pb-1) :

)()(4.45.169 7.16.1 systJESstatmt

+−+±=

)(0.6)(2.46.170 syststatmt ±±=

)(1.7)(8.55.177 syststatmt ±±=

)(07.0)(13.00.0 syststatf ±±=+

Search for single top quark production in pbarp collisions at sqrt(s)=1.96 TeVPhys. Lett. B {622}, 265-276 (2005). hep-ex/0505063; Fermilab-Pub-05/207-E.

DOE Review 2/13/06

B. Quinn University of Mississippi

5

Top Results (Preliminary)Top Results (Preliminary)Pair production cross section

All jets, SVT b-tagging (350 pb-1):

Dilepton (370 pb-1):

eµ, Lifetime b-tagging (350 pb-1):

Lepton+jets, lifetime tagging (365 pb-1):

pb)(3.0)()(2.5 5.10.1

6.25.2 lumisyststattt ±= +

−+−σ

pb)(6.0)()(6.8 2.10.1

3.20.2 lumisyststattt ±= +

−+−σ

pb)(7.0)(4.1)(1.11 8.53.4 lumisyststattt ±±= +

−σ

pb)(5.0)(1.8 3.12.1 lumisyststattt ±+= +

−σ

Measurement of the ttbar cross section in pbarp collisions at sqrt(s)=1.96 TeV using kinematic characteristicsof lepton plus jets events. Phys. Lett. B {626}, 45 (2005). hep-ex/0504043; Fermilab-Pub-05/079-E.

Measurement of the ttbar cross section in pbarp collisions at sqrt(s)=1.96 TeV using lepton plus jets events with lifetime b-tagging. Phys. Lett. B {626}, 35 (2005). hep-ex/0504058; Fermilab-Pub-05/087-E.

Measurement of the ttbar production cross section in pbarp collisions at sqrt(s)=1.96 TeV in dilepton final states.Phys. Lett. B {626}, 55 (2005). hep-ex/0505082; Fermilab-Pub-05/217-E.

Lifetime b-tagging:Secondary Vertex Tagger

DOE Review 2/13/06

B. Quinn University of Mississippi

6

σσtttt lepton+jets Analysis With lepton+jets Analysis With Lifetime TaggingLifetime Tagging

Single tagged events Double Tagged Events

(lumi)pb50syst)(stat1.8 3.12.1 .σ tt ±+= +

−

DOE Review 2/13/06

B. Quinn University of Mississippi

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Last Year’s Outlook:Last Year’s Outlook:Where do we go from [Where do we go from [t]heret]here??

Statistics are coming…Systematics have improved little over the past year

Reprocessing entire Run II data setBetter calorimeter calibrations and object ID

Upgrade Silicon Microstrip Tracker with new inner Layer 0 detector (L0)

Greatly enhanced b-tagging efficiency

* DONE!

* Feb. 27!

* Now have > 1.1 fb-1 Int. Lumi.

* Have improved much over this year!* Have improved much over this year!

DOE Review 2/13/06

B. Quinn University of Mississippi

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Upgrade ProgressUpgrade ProgressDØ Trigger and Layer 0 hardware upgrade projects met their aggressive schedules and were ready to install for the previously scheduled October shutdown

Zebra mussels and other considerations gave us another few months to simulate, test, and exercise systems

Standing Committee on Upgrade Installation to Physics Standing Committee on Upgrade Installation to Physics Commissioning (SCIPC):Commissioning (SCIPC): 16 member group charged with developing a full upgrade Inst. & Comm. plan

Working Group 5 (Layer 0):Working Group 5 (Layer 0): Breese QuinnBreese Quinn, Ela Barberis, Bill Cooper, Eric Kajfasz, Elizaveta Shabalina, Taka Yasuda, Eckhard von ToerneSCIPC finished its work and was disbanded on 01/06/06!

DOE Review 2/13/06

B. Quinn University of Mississippi

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SCIPC: WG5 L0 timelineSCIPC: WG5 L0 timeline

DOE Review 2/13/06

B. Quinn University of Mississippi

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L0/SMT UpgradeL0/SMT UpgradeL0/SMT Software

WG5 recommended that D0 form a new L0/SMT Software Group identified a major gap in manpower

Responsibility to develop all software necessary to integrate L0 with the existing SMT, and to take over maintenance and upgrade of most existing SMT software

Online, Offline, Simulation … everything!Alex Melnitchouk was appointed Group Leader

L0/SMT Software Group completed all work needed to install and commission L0

Software challenges on cosmic ray data have been successfulGroup is prepared now to start commissioning in three weeks.

L0 Bias Voltage SystemQuinn’s final task for L0 is the installation and commissioning of the L0 bias voltage system

This work will be completed the weekend before the shutdown, which occurs on February 27.Also includes a significant rearrangement of existing SMT bias voltage distribution

DOE Review 2/13/06

B. Quinn University of Mississippi

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CP Violation in Top QuarksCP Violation in Top QuarksSM CP Violation is too weak to account for the matter dominated universe

K and B systems are only places in which CP observed

Top quark CP arising in SM extensions could account for the observed baryogenesis asymmetry

SM CP in top is negligible due to GIM cancellations resulting from the large top massThe large top mass is exactly what leads to strong couplings to CP phases in new physics

2HDM – CP from scalar-pseudoscalarmixing in 1-loop top quark-lightest neutral Higgs exchangeMSSM – 1-loop top quark exchanges with stops and gluinosCEDM – large CP top chromo-electric dipole moment can arise in 2HDM and MSSM 1-loop diagrams

g

g

t

t_

gt

t~

~~

g

g

t

t_

gt

t~

~~

DOE Review 2/13/06

B. Quinn University of Mississippi

12

Top Quark CP Research ProgramTop Quark CP Research Program

Top quark CP observables at the Tevatrontt pair production: dilepton events lepton+jets events

Could probe down to ~10-17

(>1 order of mag. short of expectation)

s-channel single top:At 8 fb-1, 6% asymmetry could be measured to 3σ (within factor of 2 away of some regions of MSSM phase space)Not likely to be accessible at LHC due to overwhelming tt and W-gluon fusion background

( ) ( )( ) ( ).−++−

−++−

>+>>−>

=TTTT

TTTTt EEEE

EEEEAσσσσ ( ) ( ).

σσσ TcutTTcutT

cutEEEEA >−>

=++−−

.0btbt

btbtAσσσσ

+−

=

( ) ( ) ( ).11

+++++++ ++= TDDTPPTT

EfcEfcEfdEdσ

σ

DOE Review 2/13/06

B. Quinn University of Mississippi

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Top Quark CP Research ProgramTop Quark CP Research ProgramD0 Research Plan

CEDM: tt cross sectionAcut using D0 lepton+jets cross section with b-tagging

Analysis is very mature and 1 fb-1 data set is availableNot the most sensitive observable, but quick first step

CEDM: tt lepton EtCP coupling weighted lepton energy spectrum is more sensitive and more challenging

Use Matrix Element/Optimal use of information method Developed at D0 by Estrada, Canelli, Gutierrez, used for mt and W Helicity measurements

I gained familiarity with method when I served on W Helicity EB

2HDM/MSSM: single top 1-loop asymmetriesDepends on using all s-channel events, most notably all-jet events

Benefit from new L0: enhanced b-tagging and improved high-multiplicity tracking in jetsDraw on experience of Melnitchouk (L0 tracking and software, advanced analysis methods in Higgs searches, serves on high-Pt jet production EB) and Quinn (SMT/L0 work, top b-tagging, single top and W helicity EBs)

Task Personnel 1Q 2Q 3Q 4Q 1Q 2Q 3Q 4Q 1Q 2Q 3Q 4Q 1Q 2Q 3Q 4Q

b-tagging development BQ

l+jets x-sec anlysis BQGS

l+jets Et spectrum analysis BQ

L0/tracking commissioning BQAM

single top Editorial Board BQ

single top analysis BQAM

BQ: Breese Quin, PI AM: Alexander Melnitchouk, postdoc GS: gradate student

Project Period2006 2007 2008 2009