The CDF Group at LBNL

LBNL DOE Review, March 1-2, 2006

Angela Galtieri

Outline

Status of the Tevatron

LBNL Group

CDFII Detector

Contributions to CDFII

Hardware

Operation

Recent Contributions to Analysis Tools

Physics Program

B physics

Top Physics

New Phenomena

Summary and Conclusions

Tevatron Status and Plans

Tevatron has been doing very well. It

is on the Design curve.

Needs to improve pbar stacking rate to 30 mA/hr to stay on the Design curve

Record luminosity: 1.72x1032

Presently have 1fb-1 good runs with Silicon, mostly processed

we are here

September 2005

Members of the LBNL Group

Physicists-Staff (2.0FTE)

A. Galtieri

J. Beringer**

C. Haber*

J. Lys *

M. Shapiro* (UC Berkeley)

J. Siegrist* (UC Berkeley)

W. Yao**

Physicists-Term (2 FTE)

A. Cerri

J. Nielsen

Fellows (1 FTE)

P. M. Fernandez

Grad. Students(5.0FTE)

H. Bachacou (now Orsay)

J. Freeman

A. Deisher

J. Muelmenstaedt

P. Lujan

Undergrad. Students (1FTE)

M. McFarlane

*ATLAS, ** PDG

FTE refer to FY06

Guest

I. Volobouev

A. Gibson (PHD '06)

H. C. Fang

CDF recent upgrades

Improved photon detection

EM calorimeter: timing readout added

Central preshower: wire chambers replaced with scintillation tiles

DAQ upgrade

To match the trigger: 20MB/sec -> 60 MB/sec

Trigger Upgrade

30KHz(L1), 1KHz(L2) 100Hz(L3)

LBNL Contributions : Silicon detectors, COT, TOF

Commissioning, Operation, Software

CDFII Detector

Forward

muon

Endplug

calorimeter

Silicon and drift chamber trackers

Central muon

Central calorimeters

Solenoid

TOF

Silicon Detectors: LBNL contributions

SVX’

1990

SVX2

1996

SVX3

1998

SVX4

2002

LBNL designed SVX, SVX'.

Joint designs with FNAL since.

SVX3 used in CDFII RUN 2b R&D and prototyping

SVX4: developed for Run 2b Project canceled due to budget cut. Chip used by D0, Phenix at BNL

Conversion to .25 micron CMOS technology proposed by LBNL. Also used by ATLAS' pixel chip

Hybrids and “stave” (new detector concept : integrated electrical, mechanical and cooling unit) being evaluated by ATLAS

Silicon detectors transformed physics capabilities of CDF since early '90.

LBNL is a major player in Vertex Detector technology. Long standing

tradition, now applied to LHC.

SVT, displaced vertex trigger

Extended B physics capability

Rad hard chips for Silicon Detectors

LBNL Contributions to CDF II

I. Construction

Silicon detectors

SVX3 chip (co-design with FNAL), test, probe

hybrids for L00, SVXII, ISL

associated electronics

Drift Chamber (COT)

inner cylinder, field sheets

Conceptual design of alignment

Time calibration system

II. Commissioning

COT Associate Project Manager

COT Commissioning

Silicon commissioning

III. Operation

CDF II Operation Manager

SVT operation

Silicon Operation (ongoing, see later)

IV. Computing and software

Project manager

Codegen for relational data bases

Data handling software for early tests

Silicon Code librarians

TOF

Study laser calibration system

Install fibers, online monitoring

LBNL Recent Contributions to CDFII

Silicon calibration ( Nielsen)

Silicon good run list (P. Lujan)

SVT online monitoring checks, SVT hardware support, upgrade code consultant (A. Cerri)

DAQ shifts (3 months service) (FY04-05: 3 students, one fellow)

SCI-Co or CO shifts (everybody)

moved to other groups

Online silicon monitoring (to John's Hopkins)

Online data monitoring (YMON) (to Rochester))

COT calibration (to FNAL)

SVT data taking: pager (to Pisa)

Detector Operation (MOU)

MC: EVTGEN, B decays generator (Juerg Beringer)

GFLASH tuning (P. Fernandez)

SVT simulation (A. Cerri) moved to other groups

MC generators : ISAJET (Galtieri), HERWIG, Wbbgen (Lys), ZGRAD (Gibson)

Silicon geometry (A. Dominguez)

Passive material (L. Vacavant)

Silicon Tracking (W. Yao)

Secondary vertices code (W. Yao, A. Dominguez)

Software Responsibilities (MOU)

Contributions to Analysis Tools 2005-6

EVTGEN: improved B decays simulation (Beringer)

Trigger efficiency for electrons (for all High PT physics groups)

Improved offline code, Gen5, and validation for top group analysis.

Validate Gen6 using W cross section data (Freeman,Nielsen)

Improved Scale Factor (data/MC) for electron ID (McFarlane, Yao)

Trigger studies for B physics (improve Bs mixing measurement)

Improved impact parameter resolution (better Bs mixing sensitivity)

Silicon b tagging high PT (efficiency, scale factor, NN)

Jet corrections and systematics (smaller systematics on top mass)

Exploit group expertise to optimize data taking and detector performance.

Develop reliable tools to perform physics analysis.

Essential for precision measurements.

Displaced vertex b-tagging (SECVTX)

H. Bachacou, P. Lujan, M. McFarlane, J. Nielsen, W-M Yao + others

Displace vertex agorithm important for tagging b quarks products. B physics, top physics, Higgs etc.

tt event efficiency = (60±3)%

Efficiency for second tag in top events (25±2)%

Efficiency ratio between data and MC (89± 7)%

Displaced vertex algorithm allows detection of b quarks, important for B physics, top, and Higgs



xy~150 

Combine SECVTX (reconstructed

secondary vertices) with

JetProb (single displaced tracks).

Improved efficiency by ~25%

adding jets that were not tagged

Reduced backgrounds from c and light quark jets by ~fac. 2

Retain 90% of b-tags

light q jets-b jets

charm jets-b jets

NN improved tagging efficiency.

95% b effic.

95% b effic.

Jet Corrections and systematics

Run2

Pedro Fernandez, L. Galtieri, A. Gibson

Long standing expertise on jets in LBNL group (since 1986).

Run2 systematic uncertainties now smaller than Run1

Reduced DMtop syst.. by fac. 2

Systematics on jet PT

Paper submit. to NIM (10/'05)

Work in progress

Run 2

Large sample of isolated tracks

Tuning of GFLASH can be extended to 35 GeV (from 5 GeV)

Lateral tuning of GFLASH will help reduce Out-of-Cone syst.

E/p for isolated tracks

syst. from 4% to 1-2%

Present syst. on E/P

Publications 2004-2006

Papers published or accepted for publication

ttbar Cross Section with Secondary Vertex b-tagging (Bachacou PHD)

Moments of Hadronic Inv. Mass Distribution in Semileptonic Decays

F-B Charge Asymmetry in e+e- pairs (Veramendi PHD Thesis)

Combined limit for Higgs Production (Run I)

b-bbar correlations (A. Affolder PHD thesis, Run I)

Partial Widths and Search for Direct CPV in D0 Decays to K+ K- and + -

Inclusive cross sections of pp --> W and Z

SM Higgs, H/A into tau-tau (A. Connolly PHD thesis, Run I)

Bs/B0 Ratio of Branching Fractions

Top Mass in Lepton+Jet Channel using a Template Method (Brubaker PHD thesis)

Search for Particles Decaying into bb with associated W Production

Will highlight only a few of these analyses here

B Physics: where are we?

Bs mixing requires fully reconstructed decays to reach high values of xs and eventually will lead to measurements of the angle 

Initially Bs semileptonic decays , high statistics, can be used

LBNL Group working on Bs mixing. Published work on Vcb.

CP violation in the B system constrains the unitary triangle.

SM requires a+b+g=p, Sin2 well measured at the B factories.

SVT (Silicon Vertex trigger) allows study of the hadronic decays B hh and Bs Ds 

It opens whole new window that can lead to new physics

Bs physics can only be done at the Tevatron

Vcb

CP violation in Bs  J/ is new physics

Bs mixing

BsKK,

Cabibbo suppressed B¯ Do K¯

Motivations: measure the angle , via three branching ratios:

BR(B¯  Do K¯)/BR(B¯ Do ¯) and

BR(B- DoCP± K-) /BR( B-DoCP± ¯)

H-C. Fang (PHD thesis), M. Shapiro, others

Direct CP-violation in B DCP± K (M. Gronau, PRD 58, 037301) predicts

B- DoCP± K  B+ DoCP± K). Model allows extraction of the angle 

Selection optimized for B-  Do K­

Recent fit to templates for known processes(left). Using Particle ID (right)

Small background

ND0π = 8054± 101

Ns ~ 670

M (Do ¯) GeV

M (Do -) GeV

Use DE/dx for - separation

1.4  at P ~ 2 GeV

Bs Mixing at CDF

SM Fit: ms = 22.2 ± 3.1 ps-1

To measure CPV in the Bs system we need to measure ms from Bs-Bs oscillations. Amix ~ Dcos(mst)

ms expected to be large due to coupling to top quark

Bs fully mixes in < 0.15 lifetimes !!

−

B mixing World Average @95 C.L. Uses data from LEP and SLD ∆ms ≥14.5 ps-1

 ~ 5%

Bs mixing Analysis

Lxy



ct =

Procedure

B Reconstruction

hadronic: good pT resolution, small statistics

semileptonic : bad pT resolution, large statistics

Measure flavor taggingat production (calibrate with Bd)

Measure time dependent asymmetry

N(t)mixed -N(t)unmixed

N(t)mixed +N(t)unmixed

A(t) =

= Dcos(mst) where D=1-2Pmistag

In practice we use the amplitude analysis scan likelihood fit

Bs : fully hadronic modes

Bs mixing signals in 355 pb-1.

Bs -> Ds , Ds 3

Ds  , KK, 3

Highest ct resolution. 1118 fully reconstructed events. ct » 30

D2=(1.55 0.160.05)%

Preliminary limit:

Dms > 0.0 ps-1 @95% C.L.

Sensitivity = 9.8 ps-1

Semileptonic: Lower resolution than hadronic.... but very large statistics:

~8K events

Basic: Bs -> lvDs Sens.=10.6 ps-1

Ds -> f p, K* K, 3p ct » 60

D2=(1.55.09)%

Dms > 6.8 ps-1 @95% C.L.

Bs -> Ds

Ds  

Bs -> Ds 3

Ds  

October 2005

CDF Bs Mixing Results

New combined CDF Results: semileptonic+ hadronic modes (compared with Winter '05)

Limit : 7.9 ->8.6 ps-1 @95% CL

Sensitivity: 8.4 ->13.0 ps-1

Effect on World Average:

Limit 14.5 -> 16.6 ps-1

Sensitivity: 18.5 -> 20.0 ps-1

Tevatron Results are now improving World Average

Perform an Amplitude Analysis ℒ ~ [1±ADcos(mst)]/2

SM Fit: ms = 22.2 ± 3.1 ps-1

Bs mixing with Fourier Transform

Bs oscillations are a periodic signal: Fourier space is the natural tool

Fourier transform of data: g(ω)=Σk cos(ωtk) (tk = proper time event k)

Difference of g(ω) for unmixed and mixed events, Δ(ω):

Peaks for ω=Δ ms and is 0 everywhere else

Error on Δ(ω) ~ N/2 (N = total # events)

Can establish presence of significant

Bs mixing signal just looking at the data!

No modeling required

Other properties:

Same sensitivity as fit based Amplitude scan

Can relate Δ(ω) to fit based Amplitude

Requires modeling of expected peak height

Limits can be set as with usual Amplitude scan

Very fast computationally (no fit!)

Δ(ω)

ω=Δ ms

Cerri, Bedeschi (Pisa)

LBNL Contributions to Bs Mixing

Signif.= e

SD2

2



(xs t/)2

2

S

S+B



Optimize yield of Bs

Cuts to give best signal significance

Improvements in trigger

Use many modes (provide many samples)

Optimize vertex resolution (s t)

Primary Vertex determined event-by-event

Best possible silicon tracking

High Statistics Lifetime fitting

Optimize Tagging (efficiency(e), and Dilution(D) )

Combine many tags

Beringer, Cerri, Deisher, Muelmenstaedt, Shapiro

Working on hadronic modes

LBNL activities in areas marked in red completed, blue are in progress

Work in Progress: Increasing Bs Yield

Increase Yield by Factor of 2-3

Some loss in c resolution wrt

fully reconstructed modes

Requires careful modeling

Use partially reconstructed modes:

Fall 2005

More then x2 data being analysed

extremely aggressive

Include SSKT

Current

ct uncertainty from

0.5% full recon

5% partial r.

15% semilept.

Measure top quark properties

Mass to 3 GeV, Top cross section to 10%

Verify SM decay properties

Any non SM processes hide in top events?

Higgs production

SM Higgs: it is a big challenge, but try

SUSY: tan=50 5 discovery possible of H/A with M=175 GeV (5 fb-1)

Precision Measurements

Electroweak Precision Measurements

Increased

luminosity

Baseline

luminosity

SUSY:

Some of the parameter space for squarks and gluinos are being explored.

Long lived stable particles , trileptons, etc. Many ways to search

Many other searches: W'. Z', leptoquarks ,

technicolor, extra dimensions etc.

Prospects for High PT physics at CDF

Top Quark Property Measurements

Fernandez, Freeman, Galtieri, Gibson, Lujan, Lys, McFarlane, Nielsen, Yao

The Standard Model predicts the Higgs mass, once the W and Top mass are measured with high precision.

Loop corrections to MW proportional to Mt2 and MH

M(top) = 172.7 ± 2.9 GeV (CDF+D0 Run I+II)

M(top) = 178.0 ± 4.3 GeV (CDF+D0 Run I)

July 2005 best Fit

old:

now

MH< 186 GeV

at 95% CL

Direct limit:

MH > 114.4 GeV

at 95% CL

Fall '05 fits with M=172.7 ± 2.9 GeV

Top Physics Studies

Top events preferentially W+ 3 jets

W + JETS

p

p

g

q

q’

t

t

t t Production at the TeV:

Top quark is heavy: decays very fast!

(t -> Wb ) ~ 1.5 GeV, t=4x10-25sec

QCD = 100 Mev, -1 = 10-23 sec

No hadronization: no top mesons or baryons

6 jets

l + 4jets

2l + 2jets





e

Final states (2 b-jets + 2 W):

- dilepton (2 W❐l)

- lepton+jets (W❐l,W❐qq)

- all hadronic (2 W❐4q)

Lepton + jets channel preferred: statistics advantage over the dilepton, less backgr. then the all hadronic

2/3 signatures: lepton and ½ b jets

t t W+ b W- b

LBNL group strategy:

Understand the top candidate sample: b-tagging, backgrounds, agreement between data and Monte Carlo etc.

Optimize tools for above measurements

Look for deviations from SM

Top Cross Section Measurement

/

Understanding top candidates sample, to be used for all other top studies

LBNL: use lepton+jets channel, b-tagging to reduce background.

Bachacou(PHD), Lujan, McFarlane, Nielsen, Yao, Kusakabe(Tsukuba) +

Double tagged top event

Sample selection:

Isolated lepton, PT > 20 GeV

MET > 20 GeV (neutrino)

N (jets) ≥ 3 jets

1 b-tag by the SVX algorithm

Background : use N(jet) = 1,2 to check background calculations

Mistag

non-W QCD

Physics background: Wbb, Wcc

Single top, WW, WZ etc.

Winter '06, 695 pb-1

−

Top Cross Section (cont.)

Require, HT (total transverse energy ) > 200 GeV to reduce background

HT

CDF winter '06 averages use 750 pb-1

(made by E. Thompson)

314 tagged events, 79 have 2-tags

(70  8 back.)

HT

Lxy (mm)

Top Mass Measurements

 t ~ 5%curate at ~ 5%

The LBNL group has been involved in the measurement of the top mass

since 1993. Recent work in CDF has

involved CDF students and staff.

E. Brubaker (PHD thesis) as well as J.F. Arguin (Toronto, now Chamberlain

Fellow at LBNL) have contributed .

New: 2D fit, mass and JES (jet energy scale parameter) has

reduced the systematic error.

Analysis follows run I methodology.

252 Lepton+jets, b-tagged events

56.8±8.4 estimated background

Include 108 untagged events (41 are background)

Kinematic constraints (c2)

Compare reconstructed mass to Monte Carlo Top +background templates in a lilelihood.

Winter '06 results (700 pb-1)

Top Mass: new LBNL analysis

For each event we calculate a likelihood as a function of the top mass, integrating over phase space (d /dx) and Matrix Element M(mt) for top production and decay.

See Kondo (JPhys. Soc. 57,1988), Dalitz&Goldstein(Proc. R. Soc. Lond., A445,1999).

measured quantities parton level quantities.

Incoming partons

Fernandez, Freeman (thesis), Galtieri, Lujan, Lys, Nielsen,Volobouev

M=175.7 GeV, M=2.2 GeV

The major systematic uncertainty in top mass measurement comes from jet energy uncertainty. We use jet transfer functions (T( y | x ) to improve resolution and a JES Jet Energy Scale) parameter to transfer systematic to statistical uncertainties.

Reconstructed mass for MC events (many samples of 85 events)

M=175 GeV

LBNL Mass analysis (cont.)

kinematic discriminant

Integration done over 5 variables + jet energy scale (JES). W mass

constraint not imposed. All jet permutations used.

Use multivariate method for background separation: kinematic discriminant that combines aplanarity, Rmin, HTz.

Present data (695pb-1):126 events with 4 Jets (PT>15 GeV),  1 b-tagged jet.

Expected background of 31 events

Results being reviewed by the collaboration

Hopefully will be shown at the APS meeting in April

Reconstructed-vs-true mass has slope = 0.990.01 and bias=0.6 GeV

Search for new signals in W bb events

Techniques developed in Top analyses can be

used for other searches, for example:

pp  W X with X bb

Higgs  bb, SM cross section too small for observation in current data

Models such as technicolor predict larger 

J. Nielsen,W-M Yao, Y. Ishizawa (Tsukuba)

Even so, a search for SM Higgs helps with

understanding of backgrounds, and needed improvements.

Use top sample events with a W and 2 jets (at least one tagged jet).

In 319 pb-1, observe 187 events, with an expected background of 175±26 events

−

−

−

−

M(bb)

Njets

−

Particle searches (cont.)

Limit for SM Higgs  bb from this analysis

For MH =115 GeV: 8.6 pb at 95% CL

poor observed limit due to ~1 excess

(Results published in PRL this month)

Expected limit: 5.4 pb

SM prediction: 0.14 pb

We are about a factor 40 off!

Combine with other channels (factor ~2)

Need improvements in the analysis

More statistics (L= 3-5 fb-1 , 3  evidence)

Need more work on background estimate

Cross sections for technirho production

T WpT , pT bb

are an order of magnitude larger.

–

–

Analysis being updated with 700 pb-1

Summary and Conclusions

Large contributions to hardware and physics over the past 24 years Contributed 13 PHD thesis, 18 postdocs. 20 of these have faculty or lab staff positions.

Contributed to top discovery, precision top and W mass measurements, particle searches, properties of B mesons, Bs mixing

LBNL still contributing to Run II CDF physics results:

CKM Parameters, Bs Mixing

Top Physics

New particle searches

Will pursue this physics for the next few years.

Better statistics, improved analysis tools.

Data sample expected to be ~ 40 times the Run I data by end FY07.

Window of opportunity for high PT physics before the LHC.

Great way to prepare for the challenges of LHC physics.

DOE LBNL Presentation 2006

Backup Slides

Technical Publications in 2004-05

“The CDF Central Open Tracker (COT)”, NIM A526, 249 (2004)

“Silicon Vertex Tracker (SVT)” , NIM A518,532 (2004)

“CDF Run 2B Silicon Detector: Stave Design and Testing”,

IEEE Trans. Nucl. Science, 51, 2209 (2004)

“SVX4: A new Deep Submicron Readout IC for the Tevatron Collider”,

IEEE Trans. Nucl. Science, 51, 1968 (2004)

“The CDF Run 2B Silicon Detector: Design, ComponentsTesting”,

NIM A518, 270 (2004)

“Shielding and Electrical Performance of Silicon Detector Supermodules”,

submitted to IEEE Trans. Nucl. Science (10/04)

“Determination of the jet energy scale at the Collider Detector at FNAL”

submitted to NIM A, October (2005).

“The CDF RunIIb Silicon detector: Design, Preproduction and performance” , submitted to NIM A, October (2005).

Other Top mass measurements

Find: 32 candidate events

Expect 8.9± 1.2 background

M = 172.0±2.6(stat)±3.3(syst) GeV

A. Gibson(PHD thesis), and others

Another variation of the ME approach to top mass measurement. Uses transfer functions for jets.

Uses matrix elements for top production and decay in likelihood. Integrates over 3 variables. Narrow width approximation for the W's.

HERWIG, VECBOS MC

Uses matrix element for background as well

Top

Background

(after detector simulation)

CDF average top mass Oct-'05

M = 172.3±2.3(stat)±3.1(syst) GeV

CDF and D0 average October 05

Standard Higgs Expectation

I

SUSY Higgs can have a large cross section for large values of tan.

Study the A/H  , bb channels

Standard Model Higgs needs large integrated luminosity

LEP mH>114.4 GeV @95% CL

Need to improve

2002-04-21T14:25:46