Heavy Flavor Production and Spectroscopy with CDF · PDF fileCdf2Logo Heavy Flavor Production...

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Heavy Flavor Production and Spectroscopy withCDF

Prabhakar Palni(On behalf of the CDF Collaboration)

Department of Physics & Astronomy,University of New Mexico, USA

BEACH 2012Wichita, Kansas, 23-28 July, 2012

Prabhakar Palni (University of New Mexico) Heavy Flavor Spectroscopy with CDF BEACH 2012 1 / 43

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Outline

Outline of the talk

The Tevatron and the CDF II DetectorConfirmation of the Bottom Baryon Resonancestate ⇤⇤0

b

Probing Quark FragmentationUpsilon Spin Alignment


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Experimental Setup The Tevatron Accelerator

Statistics

The Tevatron collided p withp at 1.96TeV center of massenergy from 2001-2011Instantaneous Luminosity4x1032

cm

�2s

�1RL dt ' 12.0 fb�1 deliveredRL dt ' 10.0 fb�1 on tape,accessible for CDF II

store number1000 2000 3000 4000 5000 6000 7000 8000 90000

2000

4000

6000

8000

01/1101/1001/0901/0801/0701/0601/0501/0401/03

DeliveredAcquired

)-1Luminosity (pb


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CDF Detector CDF Detector and Particle Tracking

CDF Detector

CDF detector

Front End ElectronicsTriggers / DAQ (pipeline)Online & Offline Software

SiliconMicrostripTracker

Time-of-Flight

Drift ChamberCOT

Plug Calor. Muon

OldNew

PartiallyNew

Muon System

Solenoid

Central Calor.

Fwd Calor.

Fill gaps

Silicon Vertex Detector, Drift Chamber and TOF detectorB=1.4T and 1.5� separation between kaon andpion from TOF + dE/dX


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CDF Detector CDF Detector and Particle Tracking

Confirmation of the BottomBaryon Resonance State ⇤⇤0

b

CDF Public Note 10900


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Confirmation of ⇤⇤0b

Motivation

Heavy hadrons are the "helium atoms of QCD" where the nucleus is theheavy quark Q and the two orbiting electrons are the light diquark qq

Measurements of the masses and widths of the heavy baryons provideinput to test different non-perturbative QCD approaches to thespectroscopy of bottom hadron statesFor example: Heavy Quark Effective Theory (HQET) and Lattice QCD

⇤⇤0b

is a resonance state containing the quarks b, u, and d. LHCb hasrecently observed this state with a signal significance greater than5�(arXiv:1205:3452[hep-ex])

Goal of the analysis: Search for the ⇤⇤0b

resonant state through itsdecay to ⇤0

b

⇡+⇡�


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Resonant States Decaying into ⇤0b

Singlet

antisymmb[qq] symmb{qq}

2G

eV/c

+1/2b!

-1/2

-3/2+ 1/2"

-1*b!

-0#

-0#

-0#

-0#

+ 1/2"+0

b$2

+1

*b$2

+3

# #

p-wave

+ 1/2"+1

I=0 I=1

Pion Transitions

⇤⇤0b

, Orbital excitations:J

P = (1/2)�and (3/2)�(Strong decay)⇤0

b

, Singlet state:J

P = (1/2)+(Weak-decay)pions ⇡+⇡� are soft andemitted in p-wave


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Decay Chain of ⇤⇤0b

p

p-soft

!

+soft!

0b"

-b

!

+!

-K

p

+c"

|0

|d

P.V.

*0b"


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Masses and Q-values of ⇤⇤0b

Resonance States

Q ⌘ M(⇤⇤0b

! ⇤0b

⇡+⇡�) - M(⇤0b

) - 2m(⇡±)i.e the amount of energy released by the decay reaction

Various theoretical models predict that the mass of the first excited state⇤⇤0

b

, (1/2)� lies very close to the hadronic three-body mode thresholdwith Q⌘[20...47] MeV/c

2

The higher excited state, ⇤⇤0b

(3/2)�has Q⌘[2...17] MeV/c

2 higher thanthe lower state.


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Two Displaced Track Trigger

b-Triggers at @1.96 TeVEnormous inelastic total cross-section of �inel

tot ⇠ 60 mb�b ⇡ 20µb (|⌘| < 1.0),@1.96 TeV

Trigger on Hadronic Modes:CDF Two Track Trigger

Exploit long c⌧ (b-hadrons)Trigger on � 2 tracks withlarge |d0|p

T

� 2 GeV/c

(b production in pp )

|d0| Resolution � beam-line = 47µm

-600 -400 -200 0 200 400 6000

2000

4000

6000

8000

10000

12000

14000

16000

18000

m)µ (0SVT d

25≤ SVT2χ 2 GeV/c; ≥tP

mµ = 47 dσ

mµ

trac

ks p

er 1

0


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Signal Model

We reconstruct ⇤⇤0b

candidates in the mass difference spectrum: Q-value

Q = M(⇤⇤0b

! ⇤0b

⇡+⇡�) - M(⇤0b

) - 2m(⇡±PDG

)

Mass resolution of ⇤0b

and most of the systematic uncertainties cancelleaving only the ⇡+

soft

⇡�soft

contribution.

The signal is described by a double Gaussian to model detectorresolution.

Signal shape is fixed from the MC sample.

The background is described by a second order Chebyshev polynomial.

Q-value spectrum is obtained using full, Signal + Background model.

Used high statistics CDF D

⇤+ ! D

0⇡+soft

sample to gauge the soft pionmomentum scale for ⇤⇤0

b

soft pion candidates.

Scale is adjusted by: Q(⇤⇤0b

) = Q(⇤⇤0b

)� 0.28 MeV/c2


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Analysis Criteria

Exploit long life time andlarge mass of ⇤0

b

p

T

(⇤0b

) > 9.0 GeV/c

(Large)

c⌧(⇤0b

)/�c⌧ > 6.0

p

T

(⇡�b

) > 1 GeV/c

p

T

(⇡±soft

) > 0.2 GeV/c

|d0/�d0 |(⇡±soft

) < 3.0,w.r.t. primary VX.

]2) [GeV/cb-

! +c"Mass(

5 5.2 5.4 5.6 5.8 6 6.2 6.4

2ca

nd

ida

tes p

er

20

Me

V/c

0

2000

4000

6000

8000

10000CDF Run II Preliminary

-1 10.0 fb#L

15418 cands.#) 0b"N(


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Q-value spectrum of ⇤⇤0b

]2) [GeV/c+s!

-s!

0b

"# *0b"(rawQ

0.01 0.02 0.03 0.04 0.05 0.06 0.07

2C

andid

ate

s p

er 1

.5 M

eV

/c

0

2

4

6

8

10

12

14

16

18

20

22

24

CDF Run II Preliminary-1 10.0 fb$L The projection of the unbinned

maximum LH fit onto the binnedQ-value raw distribution of ⇤⇤0

b

candidates

Number of signal events= 17+5.3

�4.6

Q(⇤⇤0b

) = 20.68 ± 0.35MeV/c2 , Q-value scaleadjustment applied.


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Significance of the Signal

Local Significance EstimateBased on Exp. Data Fits

Signal + Background,H1(Signal Hypothesis).Background only,H0(NullHypothesis).D= �2⇤lnL1

L0= �2 ⇤ 4(lnL)

p-value is 2.28 ⇤ 10�6

Significance of the signal is4.6�

Significance Estimated with toyMC expts.

Generate Null Hypothesis H0 ,fit with H1

Parameter of interest , N

cands

Signal position Q left floatingwithin [6,50] MeV/c

2 searchwindowSignal shape fixedBackground shape floatingp-value = 2.3 ⇤ 10�4 or 3.5�


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Systematic Uncertainties on Q-value


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Summary of Results

To determine the absolute mass of the ⇤⇤0b

M (⇤0b

) = 5619.7 ± 1.2(stat)± 1.2(syst) MeV/c2

Measured Properties of the ⇤⇤0b

forRL dt ' 10.0 fb�1



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Quark Fragmentation

Probing QuarkFragmentation



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Quark Fragmentation

Quark Fragmentation

Quark fragmentation models, stringand cluster fragmentationD mesons offer solid and data basedtechnique to validate these modelsStudy charged particle productionaround heavy quarks

Kaons near D

s

and D

+ bothdecaying to �⇡Similar technique used by B

s

flavorD used for fragmentation studies

No known resonances decay toD

s

KCharged D’s do not mixSelect prompt D’s to minimizecontamination from B–>DX decays


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Quark Fragmentation

Probing Fragmentation

Charge Correlationbetween D and K

For D

+s

:Opposite sign ) earlyin fragmentation chainSame sign ) late infragmentation chain

For D

+:Random chargecorrelation


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Quark Fragmentation

Methodology-1CDF Run II preliminary - 360 pb

)2) (GeV/c+!-

K+

m(K1.8 1.9 2 2.1 2.2

2E

ntr

ies p

er 2

MeV

/c

0

10

20

30

40

50310"

+!# $s+D

+!# $+D

+!-!+

K$+

D

background

Prompt D

±s

/D

± mesons have ideally zero IP compared to finite IPof secondary components.


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Quark Fragmentation

Methodology

Particle Identification TechniquesSpecific ionization per unit track length (dE/dX) in COTTime of Flight (TOF) of the particle measured in TOF sub-detector


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Quark Fragmentation

Kaon Fraction Compared with Pythia and Herwig

Measure kaon fraction with likelihood fitTake maximum p

T

tracks in 4 R=0.7 cone around D candidates

Kaon production around prompt D

±s

is enhanced compared toprompt D

± in the opposite sign combinationPrabhakar Palni (University of New Mexico) Heavy Flavor Spectroscopy with CDF BEACH 2012 22 / 43

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Quark Fragmentation

Kaon Fraction Compared with Pythia and Herwig

Kaon production in the same sign combination is similar aroundprompt D

±s

and prompt D

±


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Upsilon Spin Alignment

Upsilon Spin AlignmentPhys. Rev. Lett. 108, 151802 (2012)


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Upsilon spin-alignment

Discrepancies in previous Upsilon spin alignment study

Differences between CDF and D0 results (⌥ polarized?)Measurement of spin alignment in s-channel helicity frame only

Angular distribution of muons from ⌥ decays

Previous experiments have only measured �✓

Does not allow to calculate rotationally invariant quantitiesBias could be introduced for non-uniform detector acceptance in �

This measurement is the first that determines the full 3D angulardistribution


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Invariant Mass Distribution of Dimuon events

550k ⌥ (1S), 150k ⌥ (2S), 76k⌥ (3S) decaying into µ+µ�

Background is dominated bymuons from b-decaysB enriched sample fromdisplaced muons is used tomodel the angular distributionof the backgroundObtain geometric acceptancefrom MC sampleCombined momentumresolution is �

p

t

/p2t

⇠ 0.07%)2) (GeV/c-µ

+µm(

8.5 9 9.5 10 10.5 11 11.5

2E

ntr

ies p

er 1

0 M

eV

/c

0

10

20

30

40

50310!


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Results

First measurement of ⌥ (3S) parametersNone of the 3 states shows evidence of polarizationVerified with frame invariance crosschecks


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Results

One-sigma confidence intervals for �✓ and �' for the ⌥ (3S) state


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Comparison of rotationally invariant quantity, �̃

Rotationally invariant quantity �̃ in CS and SH frame�̃ = �✓+3�'

1��'


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Results

Comparison of �✓,�' and �✓' as a function of p

T

for ⌥ (1S) state


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Results


T

for ⌥ (2S) state


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Results


T

for ⌥ (3S) state


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Comparison with Theoretical Models

Comparison of ↵ ⌘ �✓ for ⌥ (1S) decays in the SH frameNewer theoretical calculations have larger uncertainties


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Conclusions

Summary and Conclusions

The ⇤⇤0b

resonance is observed by the CDF at Q(⇤⇤0b

) = 20.68 ± 0.35MeV/c2 with the significance of the signal 3.5� and the local signalsignificance of 4.6�

Confirms one of the states recently observed by the LHCb Collaboration

For opposite sign charge combination: kaon production around promptD

±s

is enhanced compared to production around prompt D

±

MCs are consistent in describing early production of kaons, butdescription of kaon production later in the fragmentation is inadequate

First 3D measurement of ⌥ (3S) parameters

No significant evidence of polarization for ⌥ (nS) over a wide range of p

T


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Backup slides


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Backup slides

⌃±⇤ in CDF: PRD 85, 092011 (2012)

]2) [GeV/c!) - m(b

") - M(!b

") = M(!b

"# b$Q(

0 0.03 0.06 0.09 0.12 0.15 0.18 0.21

2ca

nd

ida

tes p

er 3

Me

V/c

0

50

100

150

200

250

300

-

b$

-1 6.0 fb%L

DataSignal + BackgroundBackground only

]2) [GeV/c!) - m(b

") - M(!b

") = M(!b

"# b$Q(

0 0.03 0.06 0.09 0.12 0.15 0.18 0.21

2ca

nd

ida

tes p

er 3

Me

V/c

0

50

100

150

200

250

300

350+

b$

-1 6.0 fb%L

DataSignal + BackgroundBackground only


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Backup slides

Results

!cos 0 0.2 0.4 0.6 0.8 1

Entri

es p

er 0

.05

0

2

4

6

8

10

12

14

163

10"

(a)

(deg)#0 30 60 90 120 150 180

oEn

tries

per

5

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1

2

3

4

5

63

10"

(b)

!cos 0 0.2 0.4 0.6 0.8 1

Entri

es p

er 0

.05

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3

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5

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7

83

10"

(c)

(deg)#0 30 60 90 120 150 180

oEn

tries

per

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1

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3

4

5

6

7

83

10"

(d)

Projections of angular variables measured in the CS and the SHframes for the range of invariant mass containing the ⌥ (1S) signal


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Backup slides

Results

!cos 0 0.2 0.4 0.6 0.8 1

Entrie

s per

0.05

0

0.5

1

1.5

2310"

= 0.47KSP

(a) 2)<8.7 GeV/c-µ+µ8.5<m(

!cos 0 0.2 0.4 0.6 0.8 1

Entrie

s per

0.05

0

0.5

1

1.5

2310"

= 0.62KSP

(b) 2)<11.4 GeV/c-µ+µ11.1<m(

(deg)#0 30 60 90 120 150 180

oEn

tries p

er 5

0

0.2

0.4

0.6

0.8

1

1.2

1.4310"

= 0.14KSP

(c) 2)<8.7 GeV/c-µ+µ8.5<m(

(deg)#0 30 60 90 120 150 180

oEn

tries p

er 5

0

0.2

0.4

0.6

0.8

1310"

= 0.23KSP

(d) 2)<11.4 GeV/c-µ+µ11.1<m(

Comparisons of projected angular distributions measured in theCS frame for prompt and displaced (error bars) dimuon samples inthe low-mass and high-mass sidebands


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Backup slides

Systematic Uncertainties

Momentum Scale: B field knowledge, uncertainty due to detectormaterial on the dE/dx correction.

Detector resolution model and its parameters.(Detector resolution is a critical parameter for our measurementsespecially for the fits of natural widths)

Choice of the background model.

Systematics propagated from the previous CDF measurement of the ⇤0b

mass.


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Backup slides

Theoretical Predictions of Masses and Q-valueReferences M(⇤0

b

) M(⇤⇤0b

, 1/2�) Q M(⇤⇤0b

, 3/2�) Q

MeV/c

2 MeV/c

2 MeV/c

2 MeV/c

2 MeV/c

2

Capstick [1] 5585 5912 47 5920 55Karliner [2] 5619.7 5929 29 5940 40Roberts [3] 5612 5939 47 5941 49Garcilazo [4] 5625 5890 �15 5890 -15Faustov [5] 5622 5930 28 5947 45Zhang [6] 5690 5850 �120 5900 -70Aziza B. [7] 5619.7 5920 20 5920 20

Q ⌘ M(⇤⇤0b

! ⇤0b

⇡+⇡�) - M(⇤0b

) - 2m(⇡±PDG

)

The predicted masses for the first excited state lie very close to thehadronic three-body mode threshold with Q⌘[20...47] MeV/c

2 and for itshigher excited state with only Q⌘[2...17] MeV/c

2 higher.

[1]S. Capstick, et al. Phys. Rev. D 34, 2809 (1986) [2]M. Karliner,et al, arXiv:0708.4027. [3]W. Roberts et al., Int. J. Mod. Phys. A23, 2817 (2008) [4]H. Garcilazo,et al. J. Phys. G 34, 961 (2007) [5]D. Ebert, et al. Phys. Rev. D 72, 034026 (2005) [6]J. R. Zhang,

et al. Phys. Rev. D 78, 094015 (2008) [7]Z. Aziza Baccouche et al. Nucl. Phys. A 696, 638 (2001)


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Backup slides

References to the Predictions of Masses and Q-value

[1]S. Capstick and N. Isgur, Phys. Rev. D 34, 2809 (1986).

[2]M. Karliner, B. Keren-Zur, H. J. Lipkin and J. L. Rosner,arXiv:0708.4027 [hep-ph].

[3]W. Roberts and M. Pervin, Int. J. Mod. Phys. A 23, 2817 (2008)[arXiv:0711.2492 [nucl-th]].

[4]H. Garcilazo, J. Vijande and A. Valcarce, J. Phys. G 34, 961(2007) [arXiv:hep-ph/0703257].

[5]D. Ebert, R. N. Faustov and V. O. Galkin, Phys. Rev. D 72,034026 (2005) [arXiv:hep-ph/0504112].

[6]J. R. Zhang and M. Q. Huang, Phys. Rev. D 78, 094015 (2008)[arXiv:0811.3266 [hep-ph]].

[7]C. K. Chow and T. D. Cohen, Nucl. Phys. A 688, 842 (2001)[arXiv:hep-ph/0003131].


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Backup slides

The Tevatron Accelerator at Fermilab near Chicago


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