latest results on b-spectroscopy from cdf

Latest results on Latest results on b-spectroscopy b-spectroscopy

from CDF from CDF

Elena Vataga (Univ. of New Mexico, Elena Vataga (Univ. of New Mexico, USA)USA)

On behalf of the CDF CollaborationOn behalf of the CDF CollaborationCERN - October 31, 2006CERN - October 31, 2006

CERN - October 31, 2006 2E.Vataga - Latest results on b-spectroscopy from CDF

Why B spectroscopy?Why B spectroscopy? We are not looking for New PhysicsWe are not looking for New Physics (but (but

may find subtle discrepancy…)may find subtle discrepancy…) Standard Model is extraordinary. Deserves Standard Model is extraordinary. Deserves

thorough elucidation.thorough elucidation. B-quark discovered in 1977. Wealth of b-B-quark discovered in 1977. Wealth of b-

mesons is found. mesons is found. Only one b-baryon well Only one b-baryon well established so far.established so far.

Effective theories derived from QCD Effective theories derived from QCD needed for dynamical understanding: needed for dynamical understanding: HQETHQET mmcc,m,mbb,m,mtt > > QCDQCD >> m >> muu, m, mdd, m, ms s Heavy Quark Symmetry Heavy Quark Symmetry

HQET extensively tested for HQET extensively tested for QqQq systems; systems; interesting to check predictions for interesting to check predictions for QqqQqq systemssystems


What’s new?What’s new?

Observation of orbitally excited BObservation of orbitally excited Bss****

mesonsmesons Observation and mass measurement Observation and mass measurement

of Bof Bc c J/J/ψψ Search for Search for bb J/ J/ψψ J/ J/ψψ Observation of new beauty baryons Observation of new beauty baryons bb

(*)(*)

ToolsTools


TevatronTevatron

today results: first fb-1

Excellent performance of Tevatron in last yearsExcellent performance of Tevatron in last years Record Instantaneous luminosity > 2x10Record Instantaneous luminosity > 2x1032 32 cmcm-2 -2 ss-1-1

Now: delivered ∫Ldt=1.8 fbNow: delivered ∫Ldt=1.8 fb-1-1

Good for b-physicsGood for b-physics on tape ∫Ldt=1.3 fbon tape ∫Ldt=1.3 fb-1 -1


coverage coverage ||| | ≤ ≤ 11

84% in 84% in

The CDF II detectorThe CDF II detector

silicon layers:silicon layers:90 cm long, |90 cm long, |ηη| ≤ | ≤ 2.02.0rr0000 = 1.3 = 1.31.6 cm1.6 cm

96 layer drift chamber 44< r <132 cm, |z|44< r <132 cm, |z|<155 cm |<155 cm |ηη| ≤ 1.0, | ≤ 1.0, 30k channels30k channels

Resolution:Resolution:ppTT~0.15% p~0.15% pTT vertex r-vertex r- ~ 30 ~ 30 μμm ; r-z m ; r-z ~ 80 ~ 80 μμmmJ/J/ψψ mass ~14 MeV/c mass ~14 MeV/c22

Trigger: 3 Trigger: 3 levelslevels25000 / 300 / 25000 / 300 / 100 Hz100 HzL1: COT tracks L1: COT tracks L2: silicon L2: silicon trackstracksdead time < 5%dead time < 5%


B physics @ TevatronB physics @ TevatronCompared to eCompared to e++ee-- experiments on experiments on (4S) or Z(4S) or Z00

Pro:Pro: pp → bb x-section is >1000 times larger pp → bb x-section is >1000 times larger (~10 (~10 b )b ) All species of b-hadrons: not just BAll species of b-hadrons: not just B/B/B00, also B, also Bss

00, , BBcc, , bb

00 Contro:Contro:

QCD background QCD background ×10×1033 larger than larger than ((bbbb) ) multiple interactions, large combinatorics.multiple interactions, large combinatorics. Collision rate ~1.7 MHz Collision rate ~1.7 MHz tape writing limit tape writing limit

~100 Hz~100 Hz

Flavor Creation (annihilation)

q b

q b

Flavor Creation (gluon fusion)

bg

g bFlavor Excitation

q q

b

g

b

Gluon Splitting

bg

g g

bqq

qq

bb

bb

gg

gg

bb

bb

gg

qq

bb

bb

qq gg gg

gg bb

bb

Flavor creationFlavor creation(annihilation)(annihilation)

Flavor creationFlavor creation(gluon fusion)(gluon fusion) Flavor excitationFlavor excitation Gluon splittingGluon splitting


B physics @ CDF: triggers B physics @ CDF: triggers are crucialare crucial

Trigger configurations:Trigger configurations: Di-muonDi-muon Lepton plus displaced Lepton plus displaced

tracktrack 2 displaced tracks2 displaced tracksSecondary Vertex Trigger (SVT) Secondary Vertex Trigger (SVT) is unique to CDF!is unique to CDF!

First of its kind to trigger on fully First of its kind to trigger on fully hadronic b/c decayshadronic b/c decays

~ 42 TB in

BCHARM

trigger!

Bhh

BR~10BR~10-5-5 visible with just visible with just trigger confirmation !trigger confirmation !


BBss and and bb mass mass measurementsmeasurements

PRL 96, 202001 2006PRL 96, 202001 2006

better precision than the current world overage!better precision than the current world overage!

220 pb 220 pb -1-1


bb Lifetime Lifetime

Measured with fully reconstructed Measured with fully reconstructed bb J/ J/ 00 decaydecay

542 542 bb candidates candidates

World best World best ((bb) measurement !) measurement !

1fb 1fb -1-1


World Average(without this result) NLO

(C.Tarantino et al.,hep-ph/0203089)

CDF NewResult

bb Lifetime vs theory Lifetime vs theory As precise as As precise as previous world previous world

averageaverage

3.1 3.1 different different though!though!


Observation of Observation of orbitally excited (L=1) orbitally excited (L=1)

BBss**** mesons mesons


Orbitally Excited BOrbitally Excited BsJsJ Mesons Mesons

jjqq JJPP BBss** DecayDecay WidthWidth

1/1/22

00++ BBs0s0 BB Broad (S-Broad (S-wave)wave)

1/1/22

11++ BBs1s1 BB** Broad (S-Broad (S-wave)wave)

3/3/22

11++ BBs1s1 BB** Narrow (D-Narrow (D-wave)wave)

3/3/22

22++BBs2s2

**BBBB**

Narrow (D-Narrow (D-

wave)wave)•B*+B+, where is undetected

•Shift of possible Bs2*, Bs1 peaks by

M(B*+ - B+) = 45.78 MeV/c2 (see PDG)

•Two channels: B+J/ψK, B+D


BB++ sample: ~58 000! sample: ~58 000!

Use Neural Network to optimize both BUse Neural Network to optimize both B++ and B and Bss****


Orbitally Excited BOrbitally Excited Bss--mesonsmesons

Two signals: Two signals: BB**

s2 s2 already seen by OPAL, DELPHI and DØalready seen by OPAL, DELPHI and DØ BBs1 s1 first observation! first observation!

Bs2*

Bs1


Discovery of BDiscovery of Bs1s1

N (B*N (B*s2s2) = 94.8 ) = 94.8 23.4(stat) 23.4(stat)

N (BN (Bs1s1) = 36.4 ) = 36.4 9.0(stat) 9.0(stat)

P-value from Toy MC ~ 2P-value from Toy MC ~ 210-710-7

Greater than 5 Greater than 5


Observation of BObservation of Bcc J/ J/ and mass and mass

measurement of Bmeasurement of Bcc


BBcc is not produced at B factories is not produced at B factories Observed in semileptonic modeObserved in semileptonic mode Full reconstruction allowsFull reconstruction allows

for precise mass measurementfor precise mass measurement New analysisNew analysis

Tune selection on BTune selection on B++ J/ J/ K K++ After approval, “open box”.After approval, “open box”. Wait for significant excessWait for significant excess Measure properties of the BcMeasure properties of the Bc

bc

cc

ud

J/Bc

Bc: changeK to a

b

c

_BBcc

±± J/ J/ψψ ±±


BBcc±± J/ J/ψψ ±±

b

c

_

m(Bm(Bcc) = 6276.5 ) = 6276.5 4.0 (stat) 4.0 (stat) 2.7(syst) MeV/c2.7(syst) MeV/c22

N(BN(Bcc) = 45.2) = 45.29.4, S/9.4, S/B = 7.5B = 7.5

theories

ChallengChallenges es

theoretictheoretical al

predictiopredictionsns


Search for Search for bb J/ J/ψψ J/ J/ψψ


IntroductionIntroduction

Spin-singlet bb bound Spin-singlet bb bound statestate

(pp (pp bbX ) ~ X ) ~ b level b level at Tevatron energy at Tevatron energy scalescale

Large uncertainty on Large uncertainty on decay branching decay branching fraction:fraction: BRBRbbJ/J/J/J/

The Bottomonium systemThe Bottomonium system_

_

b

b

_


Exclusive search from CDF RunI and Exclusive search from CDF RunI and LEP LEP

Inclusive search from CLEO Inclusive search from CLEO ( ( (nS)-> (nS)-> bb ; h ; hbb-> -> bb))

No significant evidence yet.No significant evidence yet.

Run I history (80 pbRun I history (80 pb-1-1):): 7 events observed/ 1.8 backgr. 7 events observed/ 1.8 backgr.

(2.2 (2.2 Upper limit 18 pbUpper limit 18 pb

Search for Search for bbJ/J/J/J/


Expected 3.6 bkg Expected 3.6 bkg events; observe 3 events; observe 3 eventsevents

Set upper limit for Set upper limit for production cross production cross sectionsection

31098.4)/(

)//()(

XJbpp

JJBrXpp bb

ResultsResults


Observation of new Observation of new beauty baryons beauty baryons bb

(*)(*)

http://www.fnal.gov/pub/presspass/press_releases/sigma-b-baryon.html


Bottom Baryon States with B=1,C=0,JBottom Baryon States with B=1,C=0,JPP

= 1/2= 1/2++, 3/2, 3/2++ NotationNotation Quark Quark

contentcontent JJPP SU(3)SU(3) (I,I(I,I33)) SS MassMass

bb00 b[ud]b[ud] 1/21/2++ 3*3* (0,0)(0,0) 00

5619.75619.71.21.21.2 1.2 MeVMeV

bb00 b[su]b[su] 1/21/2++ 3*3* (1/2,1/2)(1/2,1/2) -1-1 5.80 GeV5.80 GeV

bb--

b[sd]b[sd] 1/21/2++ 3*3* (1/2,-1/2)(1/2,-1/2) -1-1 5.80 GeV5.80 GeV

bb++ buubuu 1/21/2++ 66 (1,1)(1,1) 00 5.82 GeV5.82 GeV

bb00 b{ud}b{ud} 1/21/2++ 66 (1,0)(1,0) 00 5.82 GeV5.82 GeV

bb--

bddbdd 1/21/2++ 66 (1,-1)(1,-1) 00 5.82 GeV5.82 GeV

bb00’’ b{su}b{su} 1/21/2++ 66 (1/2,1/2)(1/2,1/2) -1-1 5.94 GeV5.94 GeV

bb00’’ b{sd}b{sd} 1/21/2++ 66 (1/2,-1/2)(1/2,-1/2) -1-1 5.94 GeV5.94 GeV

bb00 bssbss 1/21/2++ 66 (0,0)(0,0) -2-2 6.04 GeV6.04 GeV

bb**++ buubuu 3/23/2++ 66 (1,1)(1,1) 00 5.84 GeV5.84 GeV

bb**00 budbud 3/23/2++ 66 (1,0)(1,0) 00 5.84 GeV5.84 GeV

bb**-- bddbdd 3/23/2++ 66 (1,-1)(1,-1) 00 5.84 GeV5.84 GeV

bb**0 0 busbus 3/23/2++ 66 (1/2,1/2)(1/2,1/2) -1-1 5.94 GeV5.94 GeV

bb**-- bdsbds 3/23/2++ 66 (1/2,-1/2)(1/2,-1/2) -1-1 5.94 GeV5.94 GeV

bb**-- bssbss 3/23/2++ 66 (0,0)(0,0) -2-2 6.06 GeV6.06 GeV

Mas

s pr

edic

tions

from

hep

-ph/

9406

359

NotationNotation Quark Quark contentcontent JJPP SU(3)SU(3) (I,I(I,I33)) SS MassMass

bb00 b[ud]b[ud] 1/21/2++ 3*3* (0,0)(0,0) 00

5619.75619.71.21.21.2 1.2 MeVMeV


Predictions on Predictions on bb--(*)(*)//bb

+(*) +(*)

propertiespropertiesbb property property Expected val. Expected val.

(MeV/c(MeV/c22))

m(m(bb) – ) – m(m(bb))

180 180 210 210

m(m(bb) – ) –

m(m(bb))10104040

m(m(bb- - ) – ) –

m(m(bb++))

5 5 7 7

((bb), ), ((bb) ) ~8, ~15~8, ~15

Strong decay with Strong decay with emissionemission:

b b

NRQCD, HQETNRQCD, HQET

Potential modelsPotential models

1/N1/Ncc expansions expansions

Lattice QCD calculationsLattice QCD calculations


MethodologyMethodology

1-trk vertex

Trigger tracks Decay chain:Decay chain:

b b -(-())→→bb

00 --

bb00→ → cc

++--

cc++→ p → p

K K --++

soft track from Primary

Vertex


StrategyStrategyOptimize Optimize bb yield yield

Evaluate different Evaluate different background contributionsbackground contributions

Optimize Optimize bb

selection (MC)selection (MC)

Blind Blind bb signal region signal region

Check for possible Check for possible reflections from other B reflections from other B

decaysdecays

Estimate detector Estimate detector resolution for resolution for b b (MC)(MC)

Measure Measure bb yields and yields and

MassesMasses Set the limitSet the limit

Understandin

Understandin

g of g of

background is

background is

crucial!

crucial!

OPEN THE BOXOPEN THE BOX


Discriminating variableDiscriminating variable

Search for narrow resonances in Search for narrow resonances in Q = m(Q = m(bb)- m()- m(bb)- m()- m() )

Blinded region 0.03<Q<0.10 GeV/cBlinded region 0.03<Q<0.10 GeV/c22

Work with 2 distributions Work with 2 distributions

( expect m(( expect m(bb- - )> m()> m(bb

++) )) ) Same Charge (SC)Same Charge (SC): :

bb-(-()) → →bb

00 -- → → cc++-- -- ( ( + c.c + c.c ))

Opposite charge (OC)Opposite charge (OC): :

bb+(+()) → →bb

00 ++ → → cc++-- ++ ( ( + c.c + c.c ))

Remove Remove bb resolutionresolution

Two Two have have same/opposite same/opposite

chargecharge

bb++((buubuu) and ) and

anti-anti-bb++

5.787<m(5.787<m(bb)<5.857 )<5.857 GeV/cGeV/c22

bb--((bddbdd) and anti-) and anti-

bb--


Expected backgroundExpected background


bb sample sample

N (N (bb ) ) 86 %86 %

N (B)N (B) 10 %10 %

combcomb 4 %4 %

Signal region: [5.565, Signal region: [5.565, 5.670]5.670]

Combinatorial background

Reflections

Largest in Largest in

the World! the World!


b b optimizationoptimization

Cut are optimized with signal region blinded.Cut are optimized with signal region blinded. Signal is taken from PYTHIASignal is taken from PYTHIA Background is taken from the sidebands.Background is taken from the sidebands. Optimization is done maximizing FOM Optimization is done maximizing FOM (S)/(S)/B B No cut on pNo cut on pTT ( () )

CutCut ValueValue

PPTT ( (bb))> 9.5 > 9.5 GeV/c GeV/c

|d0/|d0/(d0) | (d0) | (())

< 3< 3

cos cos ( ()) > -0.35> -0.35

cross-check on cross-check on D*D*DD00, included in , included in

systematicsystematic


Background Background CompositionComposition

Background type SampleContribution

b b HA+UEHA+UE PYTHIAPYTHIA DominantDominant

Combinatorial

Upper b

sidebandm(b) [5.8, 7.0]

Small (~ 5%)

B mesons dataSmall (~10%)

B meson B meson reflectioreflectionsns

from B from B HA+UEHA+UE

PYTHIAPYTHIA Dominant Dominant within Bwithin B

from from

B decay (D*, B decay (D*, D**)D**)

Inclusive Inclusive BGenBGen negligiblenegligible

from B**from B** B0 PYTHIAB0 PYTHIA negligiblenegligible

replacedreplaced


Corrections to MC Corrections to MC samplessamples

PYTHIA PYTHIA bbbb Do not expect perfect Do not expect perfect

description for b-description for b-baryons – baryons – experimental data are experimental data are limitedlimited

Needs reweightingNeeds reweighting PPTT((bb))

PPTT(soft (soft ))

Included in Included in systematicsystematic


Fitting backgroundFitting background

CombinatoriCombinatorialal

B mesonsB mesons bb HA+UE HA+UE

alternative fit shapes in alternative fit shapes in systematicssystematics


Detector resolution and Detector resolution and signal widthsignal width

Estimated detector Estimated detector resolution from MC resolution from MC generating signal with 0 generating signal with 0 natural width ~ 2 MeV/cnatural width ~ 2 MeV/c22

Cross-check on D* Cross-check on D* DD00 (MC)(MC)

((bb) is predicted by HQET:) is predicted by HQET:

Dominated by natural width Dominated by natural width

Width grows Width grows with Qwith Q

hep-ph/9406359


Sum of Background FitsSum of Background Fits

Smooth Smooth background shape background shape in signal windowin signal window

Fixed fit Fixed fit parameters before parameters before opening the boxopening the box


Unblinded Q distributionUnblinded Q distribution

SamplSamplee

DataData Bkg Bkg ExcessExcess

SCSC 416416 268268 148148

OCOC 406406 298298 108108

Significant excess in

both distribution

s!

•Naïve S/(S+B) ~ 9


Fitting the signalFitting the signal Simultaneous unbinned Simultaneous unbinned

NLL fit for both NLL fit for both bb--(*)(*)//bb

+(*) +(*)

distributionsdistributions Background frozenBackground frozen 4 peaks: 4 peaks:

Breit-Wigner Breit-Wigner Gaussians Gaussians ((bb) = function (Q)) = function (Q) 7 Floating parameters:7 Floating parameters:

Num of events in 4 peaks: N (Num of events in 4 peaks: N (bb) ) Q(Q(bb

--) and Q () and Q (bb++))

Common parameter Q(Common parameter Q(bb**)-Q()-Q(bb))


Fit: values and errorsFit: values and errors

ParameterParameter ValueValue ErrorsErrors

Q (Q (bb--) [MeV/c) [MeV/c22]] 55.955.9 -0.96, -0.96,

+0.99+0.99

Q (Q (bb++) [MeV/c) [MeV/c22]] 48.448.4 -2.29, -2.29,

+2.02+2.02

N (N (bb--)) 6060 -13.8, -13.8,

+14.8+14.8

N (N (bb++)) 2929 -11.6, -11.6,

+12.4+12.4

N (N (bb* * - - )) 7474 -17.4, -17.4,

18.218.2

N (N (bb* +* + )) 7474 -16.3, -16.3,

17.217.2

Q (Q (bb**) - Q () - Q (bb) )

[MeV/c[MeV/c22]]21.321.3 -1.94, -1.94,

2.032.03

NLLNLL -24553.5-24553.5


Signal significanceSignal significance

HypothesisHypothesis (-(-ln(ln(£))£))

1/LR1/LR

““NULL”NULL” 44.744.7 2.6e192.6e19

““Two Peaks”Two Peaks” 14.314.3 1.6e61.6e6

No No bb- - peakpeak 10.410.4 3.3e43.3e4

No No bb+ + peakpeak 1.11.1 33

No No bb-* -* peakpeak 10.110.1 2.4e42.4e4

No No bb+* +* peak peak 9.89.8 1.8e41.8e4

Naïve: 9Naïve: 9 P-value calculation: > 5P-value calculation: > 5(not (not

enough Toy MC)enough Toy MC) Evaluate Likelihood Ratio for Evaluate Likelihood Ratio for

different hypothesis:different hypothesis:

4 peaks are 2.6 4 peaks are 2.6 101019 19 more likely more likely

then no peak at allthen no peak at all

Background fluctuation is Background fluctuation is statistically excludedstatistically excluded

Hypothesis with 4 peaks in Hypothesis with 4 peaks in the most favorablethe most favorable


SummarySummary We observe four We observe four bb resonant resonant

states 240 events in total states 240 events in total The significance of the signal > 5The significance of the signal > 5 The signal is consistent with the The signal is consistent with the

lowest lying lowest lying bb(()) states states

We measure Q values: We measure Q values:


PlansPlans

Increase statistics byIncrease statistics bybb

00→ → cc++-- from different triggers (~1000)from different triggers (~1000)

bb00→ J/→ J/ψψ

bb00→ → cc

+ + 33

Measure Measure m = M(m = M(bb**) – M() – M(bb) for “+” ) for “+”

and “–” separatelyand “–” separately Measure widths Measure widths


ConclusionsConclusions CDF makes fundamental CDF makes fundamental

contributions in b-spectroscopycontributions in b-spectroscopy Performing the world most precise Performing the world most precise

measurements of measurements of b b BBc c BBs s BB++ B B00 massesmasses

Discovering new particles:Discovering new particles: bb

(() ) →→bb BBs1 s1 →→ BB** BBcc J/ J/ψψ

Setting new limits: Setting new limits: bb J/ J/ψψ J/ J/ψψ

And all these with only THE FIRST And all these with only THE FIRST fbfb-1 -1 !!


BACKUPBACKUP


bb(()) masses masses

Using m(Using m(bb) = 5619.7±1.2(stat) ) = 5619.7±1.2(stat) ±1.2(syst)±1.2(syst)

Systematic Systematic ErrorsErrors

ParametParameterer

TrackinTrackingg

b b

CompComp..

b b

Norm.Norm.b b

ShapeShapereweighreweightt

Det. Det. Res.Res.

b b

widthwidthTotalTotal

bb-- Q Q

(Mev/c(Mev/c22))0.060.06

-0.06-0.060.000.00

-0.03-0.030.000.00

99

--0.000.00

22

0.0000.000

--0.0110.011

0.040.04

--0.0000.000

44

0.00.0

--0.0110.011

0.000.0099

--0.000.00

55

0.070.07

-0.07-0.07

bb+ + Q Q

(Mev/c(Mev/c22))0.060.06

-0.06-0.060.030.03

0.00.00.010.01

33

--0.010.01

33

0.0130.013

0.00.00.00.0

-0.11-0.110.00.0

--0.0140.014

0.010.01

-0.02-0.020.070.07

-0.13-0.13

bb**--bb

Q Q (Mev/c(Mev/c22))

0.060.06

-0.06-0.060.050.05

0.00.00.140.14

-0.13-0.130.040.04

0.000.000.320.32

0.00.00.020.02

0.00.00.070.07

-0.07-0.070.370.37

-0.16-0.16

bb-- events events 0.00.0

0.00.00.70.7

0.00.02.22.2

-2.2-2.20.30.3

0.00.07.47.4

0.00.00.30.3

0.00.03.43.4

-3.4-3.48.58.5

-4.0-4.0

bb++ events events 0.00.0

0.00.03.33.3

0.00.02.12.1

-2.1-2.11.21.2

0.00.02.32.3

-1.8-1.80.30.3

0.00.01.81.8

-2.0-2.05.05.0

-3.4-3.4

bb*-*- events events 0.00.0

0.00.00.40.4

0.00.04.84.8

-4.7-4.70.30.3

0.00.014.714.7

0.00.00.10.1

0.00.01.71.7

-1.7-1.715.615.6

-5.0-5.0

bb*+*+

eventsevents0.00.0

0.00.07.37.3

0.00.04.84.8

-4.8-4.82.82.8

0.00.04.64.6

-2.9-2.90.20.2

0.00.00.80.8

-0.8-0.810.310.3

-5.7-5.7


bb Motivation Motivation bb only established only established BB baryon baryon Enough statistics at Tevatron Enough statistics at Tevatron

to probe other heavy baryonsto probe other heavy baryons Next accessible baryons:Next accessible baryons:

b: b{qq}, q = u,d;

JP = SQ + sqq

= 3/2+(b* )

= 1/2+ (b )

HQET extensively tested for Qq systems; HQET extensively tested for Qq systems; interesting to check predictions for Qqq interesting to check predictions for Qqq systemssystems

Baryon spectroscopy also tests Lattice Baryon spectroscopy also tests Lattice QCD and potential quark modelsQCD and potential quark models


Fit: correlation coeff.Fit: correlation coeff.

b+ peak is small – relies on b*- b to determine it’s mean value


bb N-1 scan N-1 scan

PT (b) > 9.5 GeV/c |d0/(d0) | < 3. cos > -0.35

signalbackground


Why b baryons?Why b baryons? B-quark discovered in 1977B-quark discovered in 1977 Wealth of b-mesons is foundWealth of b-mesons is found Only one b-baryon well established so farOnly one b-baryon well established so far Finding and studying b-baryons Finding and studying b-baryons

completes tests of SMcompletes tests of SM Systematic expansion of QCD: Heavy Quark Eff. Systematic expansion of QCD: Heavy Quark Eff.

Theory:Theory: mmcc,m,mbb,m,mtt > > QCDQCD >> m >> muu, m, mdd, m, ms s Heavy Quark Heavy Quark

SymmetrySymmetry Masses and decay rates test HQETMasses and decay rates test HQET HQET extensively tested for HQET extensively tested for QqQq systems; systems;

interesting to check predictions for interesting to check predictions for QqqQqq systems systems


BBss mass measurement mass measurement

better precision better precision than the current than the current world overage!world overage!


bb mass measurements mass measurements

Observed Observed bb decaysdecays: : bb

00→ J/→ J/ψψ

bb00→ → cc

++--

bb00→ → cc

++

better precision better precision than the current than the current world overage!world overage!

-

bp

PRL 96, 202001 2006PRL 96, 202001 2006

latest results on b-spectroscopy from cdf

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