Heavy Flavor Production at the

TevatronJennifer Pursley

The Johns Hopkins Universityon behalf of the CDF and D0 Collaborations

Beauty 2006 - University of Oxford, UK September 25-29, 2006

J. Pursley, Beauty 06 2

BRAND NEW RESULT! b(*)± search

B hadron relative fragmentation fractions

B + cross section using B + → J/ K+

(1S) production cross section b→ J/J/ search and production

upper limit

Focus of this talk

See many other CDF and D0 talks for more interesting b and c results from the Tevatron!

J. Pursley, Beauty 06 3

Triggers and Data Samples Analyses use between

160 pb-1 and 1.1 fb-1 of data

Trigger paths used by these analyses: Di-Muon (J/) [CDF + D0] Displaced track + lepton

(e, ) [CDF] 2 track trigger [CDF]

Skipping all detector and Tevatron review!

D0

J. Pursley, Beauty 06 4

b Motivation b only established B baryon Enough statistics at Tevatron to

probe other heavy 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; interesting to check predictions for Qqq systems

Baryon spectroscopy also tests Lattice QCD and potential quark models

J. Pursley, Beauty 06 5

Reconstructing b With 1.1 fb-1, world’s

largest sample of b:

~3000 Use 2 track trigger to

reconstruct:

b decays at primary vertex

Combine b with a prompt

track to make a b candidate

b Mass Plot

J. Pursley, Beauty 06 6

b Search Methodology Separate b

- and b+:

(+ c.c.)

(+ c.c.)

Search for resonances in mass difference: Q = m(b) - m(b) – m

Use reconstructed b mass →

remove b mass systematic

error Unbiased optimization

Optimize b cuts with b signal

region blinded: 30 <

Q < 100 MeV/c2

b backgrounds: b Hadronization + Underlying

Event – Dominant! B meson Hadronization Combinatorial Bkg

Fix background contributions from data or PYTHIA Monte Carlo

J. Pursley, Beauty 06 7

b Observation Observe signals consistent with

lowest lying charged b states With unbinned likelihood fit,

measure events

And mass difference values:

J. Pursley, Beauty 06 8

b Fragmentation Fractions Measure flavor dependence

of fragmentation process for b quarks (non-perturbative)

Reconstruct semi-leptonic decays of B 0, B -, Bs

0, and b0

in 360 pb-1 of data ℓ –D 0, ℓ –D +, ℓ –D *+, ℓ – Ds

+, ℓ – c+

Use Particle ID likelihood cuts (important for c

+ signal) Determine sample comp.

from charm hadron BRs Indirect semi-lep decays and

excited B hadrons explicitly included

J. Pursley, Beauty 06 9

Fragmentation Fraction Results

fu, fd, fs, f = probability to result in B -, B 0, Bs0, b

0

Use B hadron transverse momentum (pT) threshold of 7 GeV/c

Agrees with world average of fragmentation fraction of B - relative to B 0

fb differs from LEP by ~2.2

J. Pursley, Beauty 06 10

B+ Production Cross Section

8197 ± 239 B ± mesons total Divide in 5 bins of pT and

measure differential cross section as a function of pT, in units of nb/GeV/c

Integrated cross section for pT ≥ 25 GeV/c = 21.7 ± 3.7 nb

Using 740 pb-1 of data, reconstruct B+ → J/ K+

To be submitted to PRD very soon…

J. Pursley, Beauty 06 11

Total B+ Production Cross Section

Combined stat & syst errors

Agrees with previous Tevatron measurements 1.8 TeV cross section

increased by 10% Also within the range of

FONLL theoretical predictions with fu = 0.389 CTEQ6M fits to parton

distribution functions

J. Pursley, Beauty 06 12

(1S) Production With 160 pb-1, reconstruct

(1S) → +-

Unresolved (2S) and (3S) signals

Previous studies at CDF limited to at √s = 1.8 TeV

Divide into three rapidity regions:

J. Pursley, Beauty 06 13

(1S) Diff. Cross Section

Little variation between rapidity regions

Also consistent with previous CDF measurement

Allows a more precise determination of parameters of bottomonium production models

Phys. Rev. Lett. {94},232001 (2005)

J. Pursley, Beauty 06 14

Search for b → J/ J/ Spin-singlet bb bound

state b yet to be observed

(pp → b X) ~ b at Tevatron energy scale

Look for b decay into

J/ J/ in 1.1 fb-1

Large uncertainty in expected BR

Expect between 0.2 and 20 events with both J/ decaying to + -

Reconstruct as 3 + track

J. Pursley, Beauty 06 15

b → J/ J/ Results Expected 3.6 bkg events; observe 3 events Set upper limit for production cross section:

J. Pursley, Beauty 06 16

First observation of lowest lying charged b states! With m(b) = 5619.7 ± 1.2 (stat) ± 1.2 (syst) MeV/c2,

Precision measurements of b production properties b fragmentation fractions (1S) and B + production cross sections Upper limit on b → J/ J/ production

More results on the way…

Summary

J. Pursley, Beauty 06 17

Backup Slides

J. Pursley, Beauty 06 18

b SystematicsParameterParameter TrackingTracking b b

Sample Sample CompComp..

b b

Ha+UEHa+UE

Norm.Norm.

b b

Ha+UE Ha+UE ShapeShape

b b Ha+UE Ha+UE

ReweightReweightDet. Det. Reso.Reso.

b b Nat. Nat.

WidthWidthTotalTotal

bb-- Q Q

(Mev/c(Mev/c22))0.06

-0.06

0.00

-0.03

0.009

-0.002

0.000

-0.011

0.04

-0.0004

0.0

-0.011

0.009

-0.005

0.07

-0.07

bb+ + Q Q

(Mev/c(Mev/c22))0.06

-0.06

0.03

0.0

0.013

-0.013

0.013

0.0

0.0

-0.11

0.0

-0.014

0.01

-0.02

0.07

-0.13

bb**--bb

Q Q

(Mev/c(Mev/c22))0.06

-0.06

0.05

0.0

0.14

-0.13

0.04

0.0

0.32

0.0

0.02

0.0

0.07

-0.07

0.37

-0.16

bb-- events events 0.0

0.0

0.7

0.0

2.2

-2.2

0.3

0.0

7.4

0.0

0.3

0.0

3.4

-3.4

8.5

-4.0

bb++ events events 0.0

0.0

3.3

0.0

2.1

-2.1

1.2

0.0

2.3

-1.8

0.3

0.0

1.8

-2.0

5.0

-3.4

bb*-*- events events 0.0

0.0

0.4

0.0

4.8

-4.7

0.3

0.0

14.7

0.0

0.1

0.0

1.7

-1.7

15.6

-5.0

bb*+*+ events events 0.0

0.0

7.3

0.0

4.8

-4.8

2.8

0.0

4.6

-2.9

0.2

0.0

0.8

-0.8

10.3

-5.7

J. Pursley, Beauty 06 19

b Fit Likelihood Ratios

HypothesisHypothesis (-ln £) 1/LR

““NULL” vs. “4 NULL” vs. “4 Peak”Peak”

44.7 2.6e19

““2 Peak” vs. “4 2 Peak” vs. “4 Peak”Peak”

14.3 1.6e6

No No bb- - PeakPeak 10.4 3.3e4

No No bb+ + PeakPeak 1.1 3

No No bb*- *- PeakPeak 10.1 2.4e4

No No bb*+ *+ PeakPeak 9.8 1.8e4

J. Pursley, Beauty 06 20

b Two Peak Fit