cdf hot topics

Beauty 05, Assisi 20-06-2005 Sandro De Cecco - FNAL & INFN Roma 1

CDF hot topicsCDF hot topics

Sandro De CeccoSandro De Cecco

FNAL & INFN Roma 1FNAL & INFN Roma 1


OutlineOutline

• Tevatron performances

• Recent and new results:– Bs mixing– b-hadrons Lifetimes & s/s

– b modes– Charmless Bd,s decays– Rare decays

• Summary and perspectives

• CDF detector and B physics triggers


Tevatron performancesTevatron performances

•CDF II has collected so far ~ 0.8 fb-1 out of >1 fb-1 delivered by Tevatron.

•Record peak luminosity is ~ 1.3∙1032 cm-2s-1

•Around 600 pb-1 are available for B physics (good tracking detector conditions)

•Current analyses use 180 - 350 pb-1 of integrated luminosity

1 fb-1 !

Right on the track of stretched TeV plans


The CDF II detectorThe CDF II detector

CDF Tracking System

Particle ID

•dE/dX in COT

•Time Of Flight detector

Lepton ID

Muons: CMU, CMP, CMX 1.1)Electrons: CEM (EM calorimeter) CPR (pre-shower detector)


B Physics at B Physics at pp colliderpp collider•All B species produced:

Bu,Bd,Bs,Bc,b, b…

•With production fractions:

fu : fd : fs : f ≈ 4 : 4 : 1 : 1

•Acceptance for other B is 20-40%

BUT: (bb) << (pp) (~65 mb) B have to be selected with specific Triggers

Primary Vertex

Secondary Vertex

Impact Parameter ( ~100m)

Lxy ~ 1 mm

B decay

•b production is so large (~300 Hz @ 1032 cm-2 Hz) that we could not even cope with writing it all to tape! trigger quasi-exclusively on specific decay modes

Example: the Secondary Vertex Trigger SVT

•Online (L2) selection of displaced tracks

based on Silicon detector hits.

see talk by Mauro Dell’Orso


B physics triggers at CDF IIB physics triggers at CDF II

1-Displaced track + lepton (e, )

120 m < I.P.(trk) < 1mm

PT(lepton) > 4 GeV

Semileptonic modes

2-Displaced tracks

PT(trk) > 2 GeV

120 m < I.P.(trk) < 1mm

pT > 5.5 GeV

fully hadronic modes

Di-Muon (J/)

Pt() > 1.5 GeV

J/ modes down to low Pt(J/)~0 (Run II)

Conventional at colliders (Run I)

+

With SVT trigger


MixingMixing


WA experimental limit:ms > 14.5 ps-1 (95%CL)

(LEP+SLD+CDF 1)

BBss Mixing Mixing

Fit with all constraints (winter 05):ρ = 0.190 ± 0.044

η = 0.349 ± 0.024

2

2

22

2

2

2

td

ts

Bd

Bs

td

ts

BdBd

BsBs

Bd

Bs

d

s

V

V

m

m

V

V

Bf

Bf

m

m

m

m

but: |Vts|>>|Vtd| ms>>md

Measuring ms/md determines |Vts|/|Vtd| Lattice calculation error O(5%)


Δms = 20.5 ± 3.2 ps-1

[14.4, 27.1] @ 95% CL

ms = 18.9 ± 1.6 ps-1

[15.7, 23.0] @ 95% CL

SM CKM-fit prediction for SM CKM-fit prediction for mms s

If ms > 30 ps-1 New Physics @ 3

(with all constraints)(Δms not used)

compatibility plot

SM New Physics modelscan allow high ms


Analysis StrategyAnalysis Strategy

• Bs signal reconstruction– Flavour specific states

• Bs decay time– proper time reconstruction – Lifetime measurement

• Initial flavour of the Bs

– Flavour tagging techniques

– calibrate on Bd mixing

mtSDAeL ttsig cos1

1 /

A

B0 Mixing perform a “Blind AMPLITUDE SCAN”:

B0 A-scan

md = 0.5ps-1 ↔ A =1


Two different BTwo different Bss signatures: signatures:Fully reconstructed HADRONIC modes:

SEMILEPTONIC modes:

D

P.V.B

,e

ss

D

P.V.

B

ss

ss DB0

XlDB lss 0

•Good proper time resolution•High Bs mass resolution•Selected by Two Track Trigger (SVT)

•Missing momentum carried by the •Diluted proper time resolution•Selected by dedicated trigger (l+SVT):


Flavour taggingFlavour taggingOpposite SideOpposite Side Same SideSame Side

Same Side Kaon: for B0s is likely to have close

in DR a K+. High D2 is expected

Soft Lepton (e,) due to bℓXℓ charge correlated to b-flavour

Jet Charge: the sum of charges of the b-Jet trackscorrelated to the b-flavour

Used for today results

NOT yet used

HADRONIC SEMILEPTONIC

md(0.503±0.063±0.015) ps-1 (0.498±0.028±0.015) ps-1

Tot. D2 (1.12±0.23)% (1.43±0.09)%

)( KDXlDB

Muon TagCalibrate the OS taggers on B0 mixing


BBss Amplitude Scan results Amplitude Scan results

Semileptonic

Hadronic

•Sensitivity: 8.4 ps-1

•Limit: ms > 7.9 ps-1 @ 95% CL


•Limit: ms > 0 ps-1 @ 95% CL

Semileptonic

Hadronic


•Limit: ms > 7.9 ps-1 @ 95% CL

CDF winter ’05 Combined

• World Average + CDF Run II

– Sensitivity: 18.2 18.6 ps-1

– Limit: 14.5 ps-1

see talk by Marco Rescigno


Near future for Near future for mmss

With the SAME data:

• Add new tagging algorithms Same Side Kaon Tag• Add more channels• Add signals from other triggers• Improve decay time resolution with PV event by event

With NEW data:

• Increased Luminosity (0.8fb-1 on tape!)• Use new trigger strategies

•2 SVT Tracks + tagging muon at trigger level (already in place since summer 2004)

x4 statistics

+20% better ct res.

•Hadronic analysis will begin to lead the sensitivity•Start to “eat” interesting ms range (expect comb. sens. ~ 15ps-1)


NEWNEW:: additional semileptonic B decays additional semileptonic B decays

From the same data (360 pb-1) usedin mixing analysis:

•Use SVT trigger (2 displaced and 2 GeV tracks)

•Select e and offline

•Allow lower LEPTON PT (42GeV)

•Increase the overall acceptance

of more than X 3

At low Lepton PT, expect more backgrounds from BDDX decays


more semileptonicmore semileptonic BBss forfor mmss analysisanalysis

+

4GeV-lepton + 1 displaced track trigger

2 displaced track trigger

Additional new sample overlap with the one already used ~ 20%

Effective ~ X 3 more semileptonic Bs yield to be used for MIXING Expect significant sensitivity increase in semileptonic ms search


b-hadron lifetimes and b-hadron lifetimes and ss//ss


•Full statistics sample still under study.

Statistical uncertainty expected:

Lifetimes in semileptonic B decaysLifetimes in semileptonic B decays

•Largest statistics B sample

•More complicated background

13,300Signal events

260 pb-1

(B+) = 1.653±0.029±0.032 ps, (B0) = 1.473±0.036±0.054 ps (B+)/(B0) = 1.123±0.040±0.040

http://www-cdf.fnal.gov/physics/new/bottom/050224.blessed-bsemi-life/

B+ 0.017 ps

B0d 0.025 ps

B0s 0.03 ps

b 0.037 ps

@ ~400 pb-1


Lifetimes in fully reconstructed modesLifetimes in fully reconstructed modes

(B+) = 1.661±0.027±0.013 ps (B0) = 1.511±0.023±0.013 ps(Bs) = 1.598±0.097±0.017 ps

•Test for our ability to understand SVT trigger biases

•Very clean samples

•Prerequisite for mixing fits

KK

CDF ’05 preliminary result


• Result (260 pb-1)– 1/4 heavy - 3/4 light state– Lifetime - heavy ~ 2 x light

• Lifetime difference measures“same” CKM element as m (oscillation frequency)

• Exciting!! Need more data– ~ 5 % sensitivity by 2009 ms = 10 ps-1 S / S = 7%

• Test still possible CP violation effect in Bs mixing

BBssJ/J/ and andssss

• BS J/ +- K+K-

• BVV decays: Heavy and Light state decay with distinct angular distributions and different lifetimes.

01.065.0 25.033.0

s

s


b-Barionsb-Barions


bb modes modes

http://www-cdf.fnal.gov/physics/new/bottom/050407.blessed-lbbr/

C. Tarantino, hep-ph/0310241 Oct 2003

b c X

•Lifetimes are an important experimental reference:–Overlap with B factories understanding of detector/trigger/analysis biases

–Further test on species not produced at B factories:

b c

NEW:

b Branching ratios:

Exp. Theo.


bb Updated knowledge Updated knowledge

Mass m = 5619.9 1.7 MeV/c2

(4.1 2.0) x 10-3

c l (5.5 1.8) %

pK + p < 2.2 x 10-5

c(2593) + l

seenc(2625)

+l seenc

++ l

seenc

0 l

seen

c+

seen

b mass

Colors:

- PDG2004

- CDF contribution beyond current PDG2004


CP violation and charmless B decaysCP violation and charmless B decays


Charmless BCharmless Bhh’hh’•Difficult competition with B factories for t-dependent tagged measurements

•Interesting B physics measurement of Bs BR and ACP(B0K)

• Signals overlap within mass resolution

• Kinematic and dE/dX to disentangle components in a combined fit:

see talk by Simone Donati

Future: measure Bs lifetimein the CP even mode KK

extract s/s


Charmless BCharmless BVV decaysVV decays

Bd→K*

~125 events ~44 events

•Measured BR( Bs) with 8 events (180 pb-1)

•Update with 360 pb-1

•Will go soon for Polarization Amplitude analysis

•Expected significance similar to B-factories

Bs→

see talk by Simone Donati

~225 events

Bs→J/

TTT dataoverlap with2 trigger:~20%

Future: measure s/s

in Bs penguin mode


Search for BSearch for Bs,ds,d see talk by Sinead Farrington

NEW Results (360 pb-1): BR(Bs ) < 1.6×10-7 @ 90% CL < 2.1×10-7 @ 95% CL

BR(Bd ) < 3.9×10-8 @ 90% CL < 5.1×10-8 @ 95% CL

These are currently world best limits

SM: BR(Bs) < 3.8∙10-9

Sensitive to new physics

Ex.:


… … and also at BEAUTY 05:and also at BEAUTY 05:

• Other VERY INTERESTING results from TEVATRON Heavy Flavour physics on:

– Bc meson at CDF and D0

– X(3872) at CDF and D0

see talk by William Wester

see talk by Ulrich Kerzel


ConclusionsConclusions

• CDF performed the first Bs mixing analysis in run II

• We foresee a substantial update with new samples, new data collected and improved tagging power for winter 2006

• Working to have world class measurements on b-hadron lifetimes and lifetime difference s/s

• Perform complementary studies in the field of charmless B decays: Bd,shh, Bd,sVV, help digging the penguin sector

• Huge CDF legacy of knowledge in Beauty to next generation B physics experiments.


Backup slidesBackup slides


SVT: the hadronic B triggerSVT: the hadronic B trigger

≈ 47 m ≈ 35 m + 30 m

SVT resolution Beam spot size

Online Impact parameterAvailable at Level 2 trigger (20µs latency)

convolution of transverse size of the beam spot with the impact parameter resolution of the SVT:

Impact Parameter distribution

Offline ~ 45 m

d

beam spot

COT track ( 2 parameters) 5 SVX coordinates

Impact Parameter (transverse projection)

Primary Vertex

Secondary Vertex

Impact Parameter ( ~100m)

Lxy ~ 1 mm

B decay


HadronicSemileptonic

mmss : systematic Uncertainties : systematic Uncertainties

•Physics background at low ms

•Prompt background at high ms

•Dilution scale factors and templatessystematic limited from control samplestatistics

**Systematic errors are negligible with respect to statistical in both cases**


Heavy Flavour ProductionHeavy Flavour Production

from HbX in 37 pb-1 of data!PRD 71, 032001 (2005)

Pt >

GeV/c

(y<1)b

D0 5.5 13.30.20.5

D*+ 6.0 5.20.10.8

D+ 6.0 4.30.10.7

Ds 8.0 0.750.050.22

PRL 91, 241804 (2003)

bb

cc with first 6.5 pb-1 !


Excited Heavy Flavor statesExcited Heavy Flavor states

• B**(L=1) B

– B J/K and D modes

– Important to understand impact for Same Side Kaon tagging mixing

2*2

2

2

*2

Common

45 /m B B MeV cm B B

f f B BB B


Welcome back to BWelcome back to Bcc

Hep-ex/0505076

http://www-cdf.fnal.gov/physics/new/bottom/050330.blessed-bc-jpsimu/

080.0032.0045.0245.0

/6

/6

KJBBRGeVP

JBRGeVP

tB

ctBc

106 events46.07.3 events

20011.00048.0287.6c

GeVm

•First signal of fully reconstructed Bc

•Direct mass measurement!

•Mode that gave the first evidence of the Bc (CDF Run I)

•Large yield, no clean resonance though!


Lifetimes: J/Lifetimes: J/ modes modes

This was the starting point:

•Clean unbiased sample

•Precision measurement

•Reference for biased (e.g. displaced track) triggers

•Test for the understanding of:

•Detector

•Analysis technique

•Sample composition ps008.0051.0539.1

ps008.0010.0100.0369.1

http://www-cdf.fnal.gov/physics/new/bottom/040428.blessed-lft2/

ps008.0033.0662.1


Lifetime in the hadronic Lifetime in the hadronic BBss modes modes

• Decay time

• actually measure transverse quantities:

– Lxy , PT(B)

• Un-binned likelihood fit

• Used: and

p

mLLt c /

Combinatorial background cttemplate from high mass sideband

ss DB0 ss DB0


Hadronic B-lifetimes resultsHadronic B-lifetimes results

(B+) = 1.66 ± 0.03 ± 0.01 ps (B0) = 1.51 ± 0.02 ± 0.01 ps(Bs) = 1.60 ± 0.10 ± 0.02 ps

Systematic summary

(B+)/(B0) = 1.10 ± 0.02 ± 0.01

(Bs)/(B0) = 1.06 ± 0.07 ± 0.01

± (stat) ± (syst)

(B+) = 1.653 ± 0.014 ps (B0) = 1.534 ± 0.013 ps(Bs) = 1.469 ± 0.059 ps

World Average lifetimes (exp.):

(B+)/(B0) = 1.06 ± 0.02

(Bs)/(B0) = 1.00 ± 0.01

Theory prediction (see Cecilia Tarantino CKM05):

CDF


Lifetime in the semileptonic Lifetime in the semileptonic BBss modes modes

c = 455.9 11.9 m c = 422.6 25.7 m c = 413.8 20.1 m

Combined ℓ-Ds lifetime result: 445.0 9.5 m (W.A.: 438 17 m)

statistical err .only, NOT for Averages (DØ ’05: 426 13 17 m)

Real Ds backgrounds: prompt and physics


HQET: baryon lifetimes and B momentsHQET: baryon lifetimes and B moments

B lifetimes Vcb

Dominant uncertainty comes from HQET extraction!

CDF can probe HQET and constrain it!

%183.81

0

Bb

b lifetimeC. Tarantino, hep-ph/0310241 Oct 2003

LO NLO 0B

B

0B

Bs

0B

b

LO NLO

LO NLO

http://www-cdf.fnal.gov/physics/new/bottom/030710.blessed-lambdab-lifetime/

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