1. Inclusive b-quark and upsilon production in DØ
Horst D. Wahl
Florida State University
DIS 2005,
Madison

2. Outline Tevatron and DØ detector Bottomonium ϒ(1S) production
High pt μ-tagged jet production
conclusion

3. Next to leading order
Leading order
Flavor excitation
Flavor creation
Gluon splitting

4. Recent developments Beyond NLO: resummation of log(pt/m) terms  FONLL
Changes in extraction of fragmentation function from LEP data
New PDFs
Improved treatment of experimental inputs
(use b-jets and b-hadrons instead of b-quarks)

5. Open Heavy Flavor Production
Long-standing “discrepancies” between predicted and measured cross sections now resolved; e.g. Cacciari, Frixione, Mangano, Nason, Ridolfi,JHEP 0407 (2004) 033
combined effects of
better calculations (Fixed order (NLO)+ NLL= FONLL)
relationship/difference between e+e−and hadron colliders
different moments of FF relevant
better estimate of theory errors (upward!)
new appreciation of issues with“quark-level” measurements
Total Cross sections (from CDF):
–inclusive b cross section: |y<1| 29.4±0.6±6.2 µb hep-ex/ (submitted to PRD)
inclusive c cross section: ~50x higherPRL 91, (2003)

6. B Production at the
Tevatron – Finally NLO
QCD and data agree
􀂄 PDF’s add more gluons
􀂄 Fragmentation
measurements from LEP
􀂄 define your signal – bquark,
B+, Hb
􀂄 All this can shift the same
matrix element prediction by
factor more than 2 !

7. Comments: Tevatron as HF Factory
􀂃The cross sections given on the previous slide imply
central (|y|<1) b’s at 3kHz at current luminosities
~2x this if you look out to |y|<2
central charm at 150kHz
–~2x1010 b’s already seen by CDF and DØ in Run II
–~1x1012 charm hadrons already produced(!)
⇒ Near infinite statistics for some measurements
⇒ If you can trigger...
Rely heavily on muon triggers
J/ψ decays are golden
semi-leptonic decays-
rare decays with leptons
Tracks with significant b/σb
Missing neutrals troublesome
forget o identification
all-charged decay modes

8. 􀂃Slightly different theoretical context–
Quarkonia Production
􀂃Slightly different theoretical context–
Non-relativistic QCD (NRQCD) Lepage et al., PRD (1992)
Production described by short distance cross sections ⊕ non-perturbative matrix elements for evolution to quarkonium state.
color octet modes required on top of color singlet to describe production (demonstrated by CDF in Run I)
New results from DØ: (1s) production, →µµ final state
submitted to PRL: hep-ex/

9. Solenoid, Tracking System (CFT, SMT)
The DØ Detector
Muon Toroid
Calorimeter
Just as a reminder: We are the ones with the good muon system and the new tracker.
Solenoid, Tracking System (CFT, SMT)

11. DØ tracking system Silicon Tracker Fiber Tracker Solenoid
125 cm
h=1.6
h=3
50cm
20cm
Forward
Preshower detector
Solenoid
Central Preshower detector

12. DØ - Muon detectors Toroid magnet (1.9 T central, 2.0 T forward)
Scintillation counters
PDTs (central)
MDTs (forward)
A-f Scint
Forward
Tracker (MDTs)
Shielding
Bottom B/C Scint
PDT’s
Forward Trigger Scint

13. The DØ Trigger System The DØ Trigger System
Towers, Tracks, missing ET
Some correl’s
Single Sub-Det’s
Not quite deadtimeless
Correlations
Calibrated Data
Physics Objects e,,jets,,missing ET
Simple Reco
Physics Algorithms L3 L1 L2
1 kHz
50 Hz
2 kHz
Decision time
~50ms
1.7 MHz
Decision time
100ms
Decision time
4.2ms L1
Missing L1 Fiber Tracker Trigger - expected by end of summer
Essential for low pT central muon trigger L2
Current rates:
L1/L2/L3 ~ 1600/900/50 Hz

14. Bottomonium production
Theory modeling of production
Quarkonium production is window on boundary region between perturbative and non-perturbative QCD
factorized QCD calculations to O(α3) (currently employed by Pythia)
color-singlet, color-evaporation, color-octet models
Recent calculations by Berger et al. combining separate perturbative approaches for low and high-pt regions
Predict shape of pt distribution
Absolute cross section not predicted
ϒ(1S) Tevatron:
50% produced promptly, i.e. at primary vertex
50% from decay of higher mass states (e.g. χb →ϒ(1S) )
Event selection
- luminosity: ± 10.3 pb-1
- di-muon: pT>3, tight Tracking and Calorimeter isolation cut
- invariant mass in 7 – 13 GeV

15. LO/NLO/NNLO QCD including flavor excitation gluon splitting
b-quark production
LO/NLO/NNLO
QCD including
flavor excitation
gluon splitting
each process results in different correlations between the two b-quarks.
the plots for the first points only shows LO, NLO are loop diagrams
gluon splitting (= fragmentation?) will have almost parallel b-mesons
LO will have b-mesons back to back

16. b-tagging at DØ Offline trigger level ptrel impact parameter
Secondary vertex
trigger level
Silicon Track Trigger (STT) at Level 2
impact parameter at Level 3

17. Tagging b-jets: μ
local muons only

18. Tagging b-jets: impact parameter
track
jet axis
jet axis
dca
track
Jet axis from primary vertex + calorimeter.
primary vtx
positive IP
negative IP

19. Tagging Tools: Vertexing and Soft Muons
B hadrons in top signal events
Vertex of displaced tracks
Identify low-pt muon from decay

20. Why measure ϒ(1S) production at DØ
Because we can: The ϒ(1S) cross-section had been measured at the Tevatron (Run I measurement by CDF) up to a rapidity of DØ has now measured this cross-section up to a rapidity of 1.8 at √s = 1.96 TeV
Measuring the ϒ(1S) production cross-section provides an ideal testing ground for our understanding of the production mechanisms of heavy quarks. There is considerable interest from theorists in these kinds of measurements:
E.L. Berger, J.Qiu, Y.Wang, Phys Rev D (2005) and hep-ph/ ;
V.A. Khoze , A.D. Martin, M.G. Ryskin, W.J. Stirling, hep-ph/

21. The Analysis Goal: Measuring the ϒ(1S) cross-section in the channel
ϒ(1S) → μ+μ- as a function of pt in three rapidity ranges:
0 < | yϒ| < 0.6, 0.6 < | yϒ | < 1.2 and 1.2 < | yϒ | < 1.8
Sample selection
Opposite sign muons
Muon have hits in all three layers of the muon system
Muons are matched to a track in the central tracking system
pt (μ) > 3 GeV and |η (μ)| < 2.2
At least one isolated μ
Track from central tracking system must have at least one hit in the Silicon Tracker

22. Efficiencies,… Cross section: = N(¡) d2σ(¡(1S)) dpt × dy
L × Δpt × Δy × εacc× εtrig× kdimu× ktrk× kqual =
L Luminosity kdimu local muon reconstruction
y rapidity ktrk tracking
εacc Acceptance kqual track quality cuts
εtrig Trigger
0.0 < y < < y < < y < 1.8
εacc –
εtrig
kdimu
ktrk
kqual

23. MC Data* Data vs Monte Carlo . η(μ) φ(μ) pt(μ) in GeV
To determine our efficiencies, we only need an agreement between Monte Carlo and data within a given pT(ϒ) and y(ϒ) bin and not an agreement over the whole pT(ϒ) and y(ϒ) range at once . MC
Data*
η(μ)
φ(μ)
pt(μ)
in GeV
*9.0 GeV < m(μμ) < 9.8 GeV
0.6 < | yϒ| < 1.2

24. Fitting the signal Signal: 3 Gaussians: ¡(1S), ¡(2S), ¡(3S)
Fitting a single Gaussian
recovers ~95 % of the
signal.
Background: 3rd order polynomial
m(¡(2/3S)) = m(¡(1S)) + ∆ mPDG(¡(2/3S)-¡(1S))
σ(¡(2/3S)) = m(¡(2/3S)/m(¡(1S)) * σ(¡(1S))
→5 free parameters in signal fit: m(¡(1S)), σ(¡(1S)), c(¡(1S)), c(¡(2S)), c(¡(3S))
All plots: 4 GeV < pt(¡) < 6 GeV
PDG: m(¡(1S)) = GeV
m(¡) = ± GeV
m(¡) = ± GeV
m(¡) = ± GeV
0 < |y¡ | < 0.6
0.6 < |y¡ | < 1.2
1.2 < |y¡ | < 1.8

25. Questions:
a) Why do we parametrize the signal as two Gaussians ?
b) How do we determine the shape of these two Gaussians ?
J/ψ → µµ
single Gauss
double Gauss

26. Question: Why do we use different fitting ranges for different bins ?
The fit assumes a smooth background.
We choose the fitting range accordingly.
ptϒ GeV yϒ
With increasing ptϒ the mass
peaks widens, but background
is better behaved
→ increased fitting range
We derive a systematic error
from varying our fitting range.

27. Fitting - Results
● The fitted width is pt
independent
● The resolution is ~30%
worse than in MC
● The (relative) widening
of the peak in the forward
region is reproduced by MC
Width ϒ(1S)

28. Fitting - results
Ratio of
n((2S+3S))/n((1S)

29. Normalized differential cross section
very little difference in shape of the distribution as a function of the ϒ rapidity
Good agreement with calculation of Berger, Qiu, Wang

30. Results: dσ(ϒ(1S))/dy × B(ϒ(1S) → µ+µ-)
0.0 < yϒ < ± 19 (stat) ± 73 (syst) ± 48 (lum) pb
0.6 < yϒ < ± 20 (stat) ± 76 (syst) ± 50 (lum) pb
1.2 < yϒ < ± 19 (stat) ± 56 (syst) ± 39 (lum) pb
0.0 < yϒ < ± 14 (stat) ± 68 (syst) ± 45 (lum) pb
CDF Run I:
0.0 < yϒ < ± 15 (stat) ± 18 (syst) ± 26 (lum) pb

31. Comparison with previous results
σ(1.2 < yϒ < 1.8)/σ(0.0 < yϒ < 0.6)
Pythia

32. Questions: Why does the mass peak widen in the forward region ?
How is the increased resulting smearing corrected
in the cross section ?
The tracking resolution is worse in the forward region, as the tracks
have a higher momentum and intersect with the tracking detectors
at an angle.
This trend is reproduced in our Monte Carlo.
We increase the Monte carlo resolution by 30% over the default
to match what we see in data.
The momentum scale is corrected for using the difference between
measured and PDG ϒ(1S) mass.
Question: Does the mass resolution really scale with the mass of the particle ?
Yes. Both in data (compared to J/ψ →µµ) and in Monte-Carlo.

33. Questions: Do we understand the rapidity dependence of our
correction factors k_qual and k_trk ?
Track quality cuts: At least 1 SMT hit on each track.
At least one of the tracks forming an ϒ has to be isolated.
k_trk (Tracking efficiency): The Monte-Carlo overestimates the tracking
efficiency in the forward region as it does not take the faulty SMT
disks into account.
k_qual:
SMT hit requirement: If we do find a track in the forward region in data, it
will have an SMT hit, as there is nothing else to make a track. Therefore the
SMT hit requirement affects the forward region less than the central region.
Isolation: In MC the isolation requirement is 100% efficient, i.e. we do not
loose any signal when applying it. In data we loose up to 6% of the signal, but
considerably less in the forward region.

34. Question: What is the L1 trigger efficiency per muon ?
We only determine the trigger efficiency for dimuons.
Approximately half the muons from ϒ(1S) have a pt < 5 GeV.
Trigger turn-on
curve from
Rob McCroskey
µ from ϒ(1S)
log scale
GeV

35. Effects of polarization
CDF measured ϒ(1S) polarization for |yϒ| < 0.4.
How can we be sure that our forward ϒ(1S) are not significantly polarized ?
So far there is no indication for ϒ(1S) polarization.
CDF measured α = ± 0.22 for pT (ϒ)> 8 GeV
α = 1 (-1) ⇔ 100% transverse (longitudinal) polarization
The vast majority of our ϒ(1S) has pT(ϒ) < 8 GeV
Theory predicts that if there is polarization it will be at large pT.
No evidence for polarization in our signal (|y| < 1.8); not enough data for a fit in the forward region alone.
estimated the effect of ϒ(1S) polarization on our cross-section:
Even at α = ± 0.3 the cross-section changes by 15% or less in all pT bins.
same effect in all rapidity regions.

36. Question: Why is CDF's systematic error so much smaller than ours ?
Better tracking resolution ---
CDF can separate the three ϒ resonances:
→ Variations in the fit contribute considerable both to our
statistical and systematic error.
→ We believe we have achieved the best resolution currently
feasible without killing the signal
Poor understanding of our Monte-Carlo and the resulting
large number of correction factors.
Signal is right on the trigger turn-on curve.

37. Conclusions ϒ(1S) cross-section μ-tagged jet cross section:
Presented measurement of ϒ(1S) cross section • BR(→μμ) for 3 different rapidity bins out to y(ϒ) = 1.8, as a function of pt(ϒ)
First measurement of ϒ(1S) cross-section at √s = 1.96 TeV.
Shapes of dσ/dpt show very little dependence on rapidity.
Normalized dσ/dpt is in good agreement with published results (CDF at 1.8TeV)
μ-tagged jet cross section:
Measured dσ/dpt in central rapidity region |y|<0.5 for μ-tagged jets originating from heavy flavor

38. Backup slides

39. Where do the ϒ(1S) come from ?
~ 50 % of ϒ(1S) are
produced directly.
The rest are the result
of higher mass states
decaying.
Bottomonium States

40. Fitting the signal Fitting a single Gaussian recovers ~95 % of the
Signal: 3 Gaussians: ¡(1S), ¡(2S), ¡(3S)
Background: 3rd order polynomial
m(¡(2/3S)) = m(¡(1S)) + mPDG(¡(2/3S)-¡(1S))
σ (¡(2/3S)) = m(¡(2/3S)/m(¡(1S)) * σ σ (¡(1S))
→5 free parameters in signal fit: m(¡(1S)), σ(¡(1S)), c(¡(1S)), c(¡(2S)), c(¡(3S))
All plots: 3 GeV < pt(¡) < 4 GeV
PDG: m(¡(1S)) = 9.46 GeV
m(¡) = ± GeV
m(¡) = 9.415± GeV
m(¡) = ± GeV
GeV
GeV
GeV
0 < |y¡ | < 0.6
0.6 < |y¡ | < 1.2
1.2 < |y¡ | < 1.8

41. Fitting the Signal PDG: m(¡(1S)) = 9.46 GeV 1.2 < |y¡ | < 1.8
Signal: 3 states (ϒ(1S), ϒ(2S), ϒ(3S)), described by Gaussians with masses mi, widths (resolution) σi, weights ci ,(i=1,2,3)
Masses mi= m1+ m i1(PDG), widths σi = σ1 •(mi/m1), for i=2,3
free parameters in signal fit: m1, σ1, c1, c2, c3
Background: 3rd order polynomial
PDG: m(¡(1S)) = 9.46 GeV
m(¡) = 9.415± GeV
m(¡) = ± GeV
m(¡) = ± GeV
1.2 < |y¡ | < 1.8
0.6 < |y¡ | < 1.2
0 < |y¡ | < 0.6
All plots: 3 GeV < pt(¡) < 4 GeV

42. Width from fit for ϒ (1S) with |yϒ| < 0.6
Data MC
Width (GeV)
0.25
0.15
0.1
pt (GeV)
~ ¡(1S) candidates

43. Trigger Level 1: di-muon trigger, scintillator only
Level 2: one medium muon (early runs)
two muons, at least one medium, separated in eta and phi (later runs)
Both triggers at Level 2 are ~ 97 % efficient wrt Level 1 condition.
Trigger efficiency for fully reconstructed di-muon events:
central region: 65 %
forward region: 80 %
Trigger efficiency |y(¡)| < 0.6
Data
wrt single μ
0.75 MC
0.65
GeV [pt(¡)]

44. Corrections: Local muon reconstruction efficiency
reconstruct J/ψ: muon & muon and muon & track
ε = muon & muon / muon & track
εData
εMC
|η|
central muon detector
forward muon detector

45. Corrections: Tracking efficiency
Method:
Reconstruct J/ψ using global (i.e. muons matched to a track
in the central tracking system) and local (i.e. muons that are
only reconstructed in the muon system and not matched to
a central track) muons.
global-local*
(signal events only)
global-local*
(all events)
global-local*
(local mu only)
4000
5000
350
GeV
GeV
GeV
* i.e. the local momentum of the test muon is used, whether is was matched or not.

46. Corrections: Tracking Efficiency
NJ/ψ(global & global)
NJ/ψ(global & local) + NJ/ψ(global & global)
Efficiency =
1.0
0.8
|η|

47. Corrections: Isolation and Silicon Hit Requirement
From data – Monte Carlo predicts isolation requirement to be 100% efficient.
Isolation efficiency for signal
| y(¡)| < 1.8
pt in GeV

48. Motivation
Fact: The multi-generational structure of the quark doublets requires explanation and could herald compositeness.
Under hypothesis of compositeness, deviation from point-like behavior would likely manifest in third generation.
Conclusion: g  bb may exhibit desired deviant behavior.
Explore b quark dijet mass as a possible signature.
Problem
~100:1 QCD:bb
Solutions
m tagging
2nd VTX tagging
Impact parameter
CDF: PRL 82 (1999) 2038
Fit to CDF
qQCD calculation

49. m-tagged Jet Cross-section
eT Trigger Eff
ePV Primary Vertex Eff
ej Jet Eff
em m Eff
fbm Frac b  m (Pt > 4 GeV)
fBm Frac B  m (Pt > 4 GeV)
L Luminosity
Dpt Pt bin width
sHF HF cross-section
sbg background cross-section
Correlated
Jet + m (Pt > 5 GeV)
Given the simplicity of the calculation, there are few likely sources of the excess seen in p13. These could conceivably be N
m JES (central value)
Resolution (i.e. smearing)
p13

50. p14 Analysis Summary Inclusive m-tagged jet corrJCCB (0.5 cone jets)
Standard Jet quality cuts, Standard JET Triggers
Jet tagged with MEDIUM muon
(more on this later)
DR(m, jet) < 0.5
|yjet| < 0.5
JES 5.3
Long term goal was b-jet xsec. Difficult due to no data-driven determination of b-fraction.

51. p14 Skimming Start with CSG QCD skim
Turn into TMBTrees (40M events…on disk)
Skim on Trees
Remove bad runs (CAL, MET, SMT, CFT, JET, Muon)
Remove events w/o 2 jets
Use Ariel d0root_ based package
SKIM 1:  1 leading jet has ~ MEDIUM m (P(m) > 4 GeV)
SKIM 2:  1 leading jet has ~ loose SVT

52. p14 All Data: CSG Skims
Bad runs & lumblk removed in luminosity. Only bad run removed in event counts for skims. Up until Run (07-JUN), V12.37.

53. Trigger Turn On Jet Trigger Collinear muon |yjet| < 0.5
Luminosity weighted
Statistics uncorrelated poisson
(wrong, of course)
JES corrected (5.3)

54. What is now a muon? m A layer cal
Medium muon (as defined by mID group)
At least one scintillator hit in BC.
Pt(central track) > 5 GeV
|Pt(central) – Pt(global)| < 15 GeV
Rejected if
4.25 < f (muon) < 5.15 AND
|h(detector)| < 1.1
m A layer
cal
jet
Fake m from punch-through
In a jet environment is an
issue

55. f Distribution of MEDIUM m-tagged jets (+ mycuts)
f(jet+m)
These cuts clearly improve the fake m rate.
Some residual fake m’s must persist. How many?
CHF should be higher for punch through jets?

56. Closer Look
Suspicious
JT45_TT
Pt(m)
Pt(m)

57. Pt(m) Pt(m) Closer Look Suspicious JT45_TT 4.5-5.0 4.0-4.5
Applied 10% inefficiency

58. MEDIUM m Definition
|nseg|=3 muons are muons with a A and a BC segments matched or not with a central track.
A |nseg=3| muon is medium if it has:
at least two A layer wire hits
a A layer scintillator hit
at least two BC layer wire hits
at least one BC scintillator hit (except for central muons with less than four BC wire hits).
A |nseg=2| muon is medium if it has:
at least one BC scintillator hit
at least two BC layer wire hits.
(octant 5 and 6 with |detector eta|<1.6).
A |nseg=1| muon is medium if it has:
a A scintillator hit
at least two A layer wire hits.

59. What is now a muon? m A layer cal
Medium muon (as defined by mID group)
At least one scintillator hit in BC.
Pt(central track) > 5 GeV
|Pt(central) – Pt(global)| < 15 GeV
Rejected if
4.25 < f (muon) < 5.15 AND
|h(detector)| < 1.1
m A layer
cal
jet
Fake m from punch-through
In a jet environment is an
issue

61. PUNCHLINE:
Remove the 10% inefficiency. It’s probably residual punchthrough.

62. Efficiencies…. Efficiency Detail Value 1.000 0.84 ± 0.005 0.37 ± 0.05
Trigger Eff
1.000
ePV
Primary Vertex: |z| < 50cm, ≥ 5tracks
0.84 ± 0.005 em
m Eff (geom, μ det., tracking, match)
0.37 ± 0.05 ej
Jet Eff (jet quality cuts)
0.99 ± 0.01
fbgm
Frac background  m (Pt > 4 GeV)
Pt dependent
fHFm
Frac heavy flavor  m (Pt > 4 GeV)
[0.37 ± 0.05]

63. m JES Definitions Required identically 2 jets
Pt(jet 3, uncor) < 8 OR third jet doesn’t pass jet QC
One jet contains muon, the other doesn’t.
| Df | > 2.84
Imbalance variable:
Independent variable:

64. Jet energy scale for μ-tagged jets
μ-tagged jets also have neutrinos
⇒ offset -- correction needed
Imbalance in events with 2 jets (one with, one without μ) – find 3.8% offset, not strongly pt dependent for pt in (75, 250GeV)
Scale energies of μ-tagged jets by factor 1.038
Order-randomized imbalance used to get resolution
STD JES 5.3 gives a 3.8% offset for m-tagged jets.
It is independent of Pt ( GeV). Maybe higher above that. Need to rebin and revisit the idea that the muon Pt may be mis-measured.
Same plot when scaling the m-tagged jet energies by 3.8%.

65. Energy Resolution

66. resolution
Neutrinos in μ-tagged jet  resolution worse than for jets without μ
take rms of order randomized imbalance
Parameterize, Fit (fig. (a))
Subtract (in quadrature) resolution for jets without μ  obtain resolution for μ-tagged jets (fig. (b)
Fit:
N = 7.7  4.1
S = 1.9  0.1
C = 0.0  0.1
Resolution parameterization used in “unsmearing”

67. Fitting Functions Variable Value Error N 9.56 × 107 1.7 × 106 a 3.195
0.004 b
5.61
0.04
Variable
Value
Error N1
7.62
0.32 k1
16.90
1.26 N2
3.28
0.60 k2
36.33
3.23

68. Extraction of Correction Factors
“normal”
exponential

69. Point by Point Unsmearing Factors
“normal”
Exponential
Unsmearing Error small
~5% for Pt > 100 GeV

70. PtRel at High Pt
PtRel
muon
jet

71. HF fraction of μ-tagged jet sample
Sample of jets with μ-tagged jets contains jets with μ from non-HF sources (e.g. , K decays…)
Use Pythia with standard DØ detector simulation to find HF fraction of jets tagged with muons vs (true) pt
Fit with A + B e-Pt/C
A = “plateau”,
B = “zero”
C = “turnon”

72. Systematic Error Breakdown

73. MC Comparison

74. Pythia using standard DØ MC. NLO uses NLO++ (CTEQ6L)
From Pythia, find fraction of jets tagged with muons (HF only).
Multiply NLO cross-section by Pythia muon-fraction.
This is effectively the NLO k factor.

75. Conc DØ Note and Conference note to EB025
Residual small bug in code (should have only a few percent effect).
JES error must be reduced to use this before setting limits on new physics.

76. - good tracking, vertex, impact parameter measuring performance
- Silicon Microvertex Tracker (SMT) + Central Fiber Tracker (CFT) + 2T Solenoid
- good tracking, vertex, impact parameter measuring performance
Pseudo rapidity: h = -ln(tg(q/2))
Spatial separation: △R2=△f2+△h2

78. Muon system: - 3 layer, 1 layer (A) in 1.8T Toroid - Good coverage:
central |h|<1
forward 1<|h|<2
- Muon-Tracking match  muon candidate
- fast and efficient Di-Muon Trigger

79. U’s |y|  U‘s PT  Data sample partition: Sample fit:
- Dy1: 0 ＜ |yU| ＜ Dy2: 0.6 ＜ |yU| ＜ Dy3: 1.2 ＜ |yU| ＜ 1.8
Sample fit:
- Background: 3rd order polynomial - U(1,2,3S) resonances: double Gaussian - the mass and width of U(1S) are free parameters; others are fixed relative to the mass

80. Evaluating the U(1S) Production Xsec:
with eff in different rapidity region:
The measured cross-section×BR(U(1S)mm) is as

81. - No strong dependence on rapidity observed
749±20±75
781±21±78
598±19±56
with 6% luminosity uncertainty

82. Run2 preliminary results consistent with CDF Run1

83. measurements of U production at D0 to 1.8 rapidity region
Summary:
measurements of U production at D0 to 1.8 rapidity region
The pT spectrum does not show significant
difference in various rapidity region
Results consistent with CDF RunI’s
- CDF √s=1.8TeV, |y|<0.4, ds/dy*Br =680±15±18±26 pb
- D0 √s=1.96TeV, |y|<0.6, ds/dy*Br =749±20±75±49 pb
- PYTHIA predict a factor of 1.11 from 1.8 to 1.96 TeV