measurement of relative fragmentation fractions of b hadrons at cdf karen gibson carnegie mellon...
TRANSCRIPT
![Page 1: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/1.jpg)
Measurement of Relative Fragmentation Fractions of
B Hadrons at CDF
Karen GibsonCarnegie Mellon UniversityFermilab Wine and Cheese
April 28, 2006Arbor Day
![Page 2: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/2.jpg)
2
Recent B Physics Results
B fragmentation fractions
Demure, but charming
Bs mixing
Brashly alluring
![Page 3: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/3.jpg)
3
Outline B fragmentation overview Semileptonic signal reconstruction Semileptonic sample composition Reconstruction efficiencies Fit for fragmentation fractions Fragmentation fraction results Outlook
![Page 4: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/4.jpg)
4
Outline B fragmentation overview Semileptonic signal reconstruction Semileptonic sample composition Reconstruction efficiencies Fit for fragmentation fractions Fragmentation fraction results Outlook
![Page 5: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/5.jpg)
5
B Physics at Tevatron Reconstruct all flavors of B hadrons
Bd0, Bu
+, Bs0, Bc
+, Λb0
Contrast to B factories, Υ(4S) [Υ(5S)] Bd
0, Bu+ [Bs
0]
Large dataset of B hadrons ~1 fb-1 data available for B measurements
Very large production cross-section makes Tevatron competitive w/B factories
Make exciting new measurements Bs mixing (1 fb-1)
Refine older measurements B fragmentation fractions (360 pb-1)
![Page 6: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/6.jpg)
6
B Fragmentation Probability of b quark hadronizing with an anti-quark or a
di-quark pair fq B(b → Bq)
Many models for heavy flavor fragmentation Petersen, Lund, …
B fragmentation fractions inherently empirical quantity Include B*, B** in fragmentation fractions
![Page 7: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/7.jpg)
7
Why Fragmentation Fractions? Search for Bs→μ+μ
B(Bs→μ+μ) = fu/fsB(B+J/K+)… Improvement in limit @95% CL if
Reduce uncertainty on fs/fd
fs/fd at Tevatron is higher than world average…
![Page 8: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/8.jpg)
8
Fragmentation Fraction Status Measured many times before
LEP (ALEPH, DELPHI, OPAL) fu, fd, fs, fb-baryon e+e collisions pT(b) ~ 40 GeV/c fs/(fu+fd) = 0.109 ± 0.026
Tevatron fu/fd, fs/(fu+fd), fΛb/(fu+fd) pp collisions pT(b) ~ 10-15 GeV/c CDF Run I: fs/(fu+fd) = 0.213 ± 0.038
2004 PDG, dominated by LEP
Average between two CDF Run I results
![Page 9: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/9.jpg)
9
B Fragmentation Intrigue Other ~2.5 sigma discrepancies observed
between LEP and CDF Run I = fdd + fss
0.118 ± 0.005 average measured at LEP 0.152 ± 0.013 measured at CDF Run I (110 pb-1)
The discrepancies could be due to New physics present in pp collisions OR fs is simply higher at Tevatron OR just fluctuations, etc…
Note: PDG 2004 calculates fs/(fu+fd) = 0.134 ± 0.014 when constraints are included
![Page 10: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/10.jpg)
10
B Frag. Fractions in Run II Use method similar to Run I measurement
Reconstruct five semileptonic B signals ℓD+, ℓD0, ℓD*+(→D0+), ℓDs
+, ℓΛc+ (ℓ=e,μ)
Relate to parent B hadrons Bd
0, Bu, Bs
0, Λb0
Cross-talk from excited charm states makes life complicated!
![Page 11: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/11.jpg)
11
Outline B fragmentation overview Semileptonic signal reconstruction Semileptonic sample composition Reconstruction efficiencies Fit for fragmentation fractions Fragmentation fraction results Outlook
![Page 12: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/12.jpg)
12
e+
μ+
+
K+
P+
CDF Detector Tracking chamber
Seven layers of silicon Precision detection of
displaced tracks Drift Chamber
dE/dx
Lepton Identification Electromagnetic
Calorimeter Hadronic Calorimeter Muon chambers
Thanks to the Tevatron for the great work delivering a
record luminosity!
![Page 13: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/13.jpg)
13
SVT Hardware trigger Can trigger on
displaced tracks in Run II Allows for
accumulation of large sample of B events
Uses information from
Drift chamber (XFT)
Silicon detector
![Page 14: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/14.jpg)
14
Semileptonic B Trigger New ℓ+SVT trigger in Run II
pT(ℓ) 4 GeV/c
pT(SVT) 2 GeV/c
120 μm d0(SVT) 1 mm m(ℓ,SVT) 5 GeV/c2
Run I trigger pT(ℓ) 8 GeV/c
![Page 15: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/15.jpg)
15
ℓ+Charm Reconstruction Reconstruct 5 charm signals
D+ K++ D0 K+ D*+ D0+ Ds
+ φ+, φ KK+
Λc+ pK+
Require one of charm tracks be SVT track Require a trigger lepton in vicinity
Vertex charm hadron with trigger lepton
![Page 16: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/16.jpg)
16
Signal Selection Cut on quantities which distinguish B decays
ct*(ℓD) = Lxy(P.V.→ ℓD)∙m(B)/pT(ℓD) 200 μm Inconsistent with being prompt
Lxy(P.V. → D)
pT(tracks) Probability of vertex fits to bottom and charm hadrons
![Page 17: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/17.jpg)
17
Reflection Backgrounds
Combinatorial backgrounds present beneath all signals
Significant reflection backgrounds present in two signals D+ signal contaminated by Ds
+→K+K+
Include reflection in fit to signal Λc
+ signal contaminated by D+→K++, Ds+→K+K+
Use dE/dx cut on proton in Λc+→ pK+
CDF Run II Monte Carlo
Ds→K+K+
CDF Run II Monte Carlo
D+→K++
Ds→K+K+
![Page 18: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/18.jpg)
18
Ds+ Reflection in D+ Signal
Use MC to determine reflection shape
Fit number of Ds+→+
observed in data Scale efficiency of Ds
+→+
to generic Ds+→KK++
Measure NDs
= 13.4 ± 0.8 % relative
to D+ yield in m[1.78,1.95]
Ds→K+K+
Λc →pK+
CDF Run II Monte Carlo
![Page 19: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/19.jpg)
19
μ+Charm Meson Signals
![Page 20: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/20.jpg)
20
μ+Λc Signal
No dE/dx cut With dE/dx cut on proton
![Page 21: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/21.jpg)
21
Semileptonic B YieldsSignature Yield
ℓD 46,848 ± 275
ℓD* 8,490 ± 95
ℓD+ 31,015 ± 262
ℓDs+ 3,081 ± 95
ℓΛc+ 4,739 ± 168
Run I yields used in fragmentation fraction measurement N(eDs
+) = 59 ± 10
N(eΛc+) = 79 ± 17
More than 50 times the yield in Run II compared
to Run I!
360 pb-1
![Page 22: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/22.jpg)
22
Outline B fragmentation overview Semileptonic signal reconstruction Semileptonic sample composition Reconstruction efficiencies Fit for fragmentation fractions Fragmentation fraction results Outlook
![Page 23: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/23.jpg)
23
Sample Composition Need to disentangle parent B hadrons
from lepton-charm signals Missing neutrino prevents fully reconstructing
decay at CDF Allows excited charm states to contribute to
reconstructed charm signals Cross-talk between signals
B0, B, Bs0 contribute to ℓD+, ℓD0, ℓD*+, ℓDs
+
Λb0 contributes to ℓΛc
+
Meson baryon cross talk small
![Page 24: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/24.jpg)
24
Simple Sample Composition
Simple parameterization of semileptonic B0, B decays into D0 and D
![Page 25: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/25.jpg)
25
Full Sample Composition
Consider all significant decays to
semileptonic charm signals,
including sequential
semileptonic decays.
“Physics backgrounds” e.g. B0→D+(→K++)D(→ℓX)
![Page 26: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/26.jpg)
26
Parameterization Simple example w/only ground stateN(ℓ+D)
=N(B0)×B(B0→ℓ+D−)×B(D−→K+)
×ε(B0→ℓ+D−,D−→K+)
=N(b)×fd×(B0)×Γ(B0→ℓ+D−)×B(D−→K+) ×ε(B0→ℓ+D−,D−→K+)
Extend this to all mesons Generalize notation N(ℓDi)=Σj=d,u,s N(b) × fj × (Bj) ×ΣkΓk×Bijk(Djk→Di)×εijk
Di = D−, D0, D*− , and Ds
Γk = Γ, Γ*, Γ**
Number of b quarks
![Page 27: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/27.jpg)
27
Branching Ratios Need model for semileptonic decays
Γ(B→ ℓD(*,**)) = 1/(B) x B(B→ ℓD(*,**)) Use spectator model for meson decays
Γ(B0→ ℓD) = Γ(B+→ ℓD0) = Γ(Bs→ ℓDs) ≡ Γ Γ(B0→ ℓD*−) = Γ(B+→ ℓD*0) = Γ(Bs→ ℓDs
*) ≡ Γ* Γ(B0→ ℓD**−) = Γ(B+→ ℓD**0) = Γ(Bs→ ℓDs
**) ≡ Γ**
Assume Γ+ Γ*+ Γ**= Γsℓ(B→ ℓX)
Use fixed sample composition for Λb→ℓΛcX Use PDG 2004 for known branching ratios
Use theoretical predictions and symmetry principles for unmeasured BR
![Page 28: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/28.jpg)
28
Outline B fragmentation overview Semileptonic signal reconstruction Semileptonic sample composition Reconstruction efficiencies Fit for fragmentation fractions Fragmentation fraction results Outlook
![Page 29: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/29.jpg)
29
Acceptances and Efficiencies Need relative acceptances and efficiencies
of individual ℓ+charm decays Fit to relative fractions
Use MC to determine acceptances Detector geometry Kinematic differences between lepton-charm
signals Use data to determine remaining
efficiencies which are different between charm channels
![Page 30: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/30.jpg)
30
Monte Carlo Monte Carlo is good for most kinematic
differences between lepton-charm signals ct(D), pT(tracks), etc…
Generate single B hadron directly Use input pT spectrum measured from data
Inclusive pT(b→J/X) spectrum
Separate set of Monte Carlo generated for each decay in sample composition
Separate sets of Monte Carlo for e, μ Validate with inclusive Monte Carlo samples by
comparing data and Monte Carlo e.g. B→ℓDX
![Page 31: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/31.jpg)
31
Reconstruction Efficiencies Measure some efficiencies from data
Single track efficiency D0→K+ vs. D+→ K++
XFT trigger efficiencies for p, K, dE/dx efficiency for cut on proton
Λc+→pK+
Use to re-weight Monte Carlo for total efficiency
![Page 32: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/32.jpg)
32
Single Track Efficiency Efficiency to add an additional track
depends on environment in detector Monte Carlo only generates B hadron
Reconstruct D0→K++ Measure efficiency relative to D0→K+ in data
and Monte Carlo Efficiency to add two additional tracks
Measure trk = 87.8 +2.1
-1.2 (stat.+sys.)%
![Page 33: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/33.jpg)
33
XFT Efficiencies Differences in tracking p, K, in drift
chamber Differences in efficiencies between
reconstructed charm states Only applies to SVT trigger track Varying drift chamber performance not
optimally described by Monte Carlo Again measure from data
Re-weight Monte Carlo Measure in separate run ranges
![Page 34: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/34.jpg)
34
XFT Efficiencies
10 [GeV/c] 2 [GeV/c]
![Page 35: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/35.jpg)
35
Comparison of Data and MC
2/NDF=24.3/27.0 2/NDF=11.9/8.0
* from eD*
![Page 36: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/36.jpg)
36
B Meson pT Spectra
Choice of pT spectrum used is important for determination of efficiencies
Use inclusive pT(b→J/X) spectrum measured in Run II for meson signals Good agreement with data
![Page 37: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/37.jpg)
37
Λb pT Spectra
Inclusive pT(b→J/X) spectrum does not describe the ℓΛc data Observe softer spectrum in data than the MC
Tune the ℓΛc Monte Carlo spectrum to match the ℓΛc data
![Page 38: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/38.jpg)
38
Outline B fragmentation overview Semileptonic signal reconstruction Semileptonic sample composition Reconstruction efficiencies Fit for fragmentation fractions Fragmentation fraction results Outlook
![Page 39: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/39.jpg)
39
General Idea of Fit Express each term of sample composition in
terms of B0
Fit for relative productionNpred(ℓDi)= N(B0) Σj=d,u,s fj/fd × (Bj)
×ΣkΓk ×Bijk(Djk→Di)×εijk
Npred(ℓΛc)= N(B0) × [fΛb/(fu+fd)](1+fu/fd)
×[(ΣkBk (Λb →ℓΛc,k→ Λc))×εk]
² fit to 5 lepton charm channels fu/fd, fs/(fu+fd), fΛb
/(fu+fd)
fs/fd = [fs/ (fu+fd)] ×(1+fu/fd)
N(B0) Parameter for fit, not physical number of B0’s
![Page 40: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/40.jpg)
40
Implementation of Fit
Fit looks like² = Σi=1..5 (Npred(ℓDi) −Nmeas(ℓDi))²/σmeas,i²
+ (Γ−ΓPDG)²/σΓPDG²
+ (Γ*−Γ*PDG)²/σΓ*PDG
²
+ (Γ**−Γ**PDG)²/σΓ**PDG
²
Gaussian constraints for Γ, Γ*, Γ**
Test with high statistics toy Monte Carlo
![Page 41: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/41.jpg)
41
Fit Results
Statistical errors ONLY Fit e+SVT and μ+SVT separately
Cancel lepton ID efficiencies Statistically independent samples
Results are consistent- very nice! Results are consistent if fu/fd fixed to unity
fΛb higher than previously
measured!
2004 PDG w/o constraint:fs/(fu+fd) = 0.109 ± 0.026fΛb
/(fu+fd) = 0.133 ± 0.023
with all constraints:fs/(fu+fd) = 0.134 ± 0.014fΛb
/(fu+fd) = 0.125 ± 0.021
![Page 42: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/42.jpg)
42
Outline B fragmentation overview Semileptonic signal reconstruction Semileptonic sample composition Reconstruction efficiencies Fit for fragmentation fractions Fragmentation fraction results Outlook
![Page 43: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/43.jpg)
43
Systematic Uncertainties Measurement is dominated by systematic
uncertainties Largest come from unknown branching ratios,
particularly ground state charm Other source of systematic uncertainty arise
from determination of efficiencies, counting yields, and false lepton backgrounds
Knowledge of the Bs0 and Λb
0 pT spectrum Residual false lepton contamination
![Page 44: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/44.jpg)
44
Λb pT Spectrum Uncertainty
Vary tuned ℓΛc spectrum to match agree with inclusive J/ spectrum Produces large
uncertainty: ±0.049 Estimate
conservatively True Λb
0 spectrum isn’t known
![Page 45: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/45.jpg)
45
Systematic Uncertainties
+0.062 -0.074 +0.058 -0.035 +0.141 -0.103
![Page 46: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/46.jpg)
46
pT Threshold for Measurement
Choose to quote pT threshold for all fragmentation fractions pT(B) 7 GeV/c determined from Monte Carlo
CDF Run II Monte CarloCDF Run II Monte Carlo
![Page 47: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/47.jpg)
47
Final Results
Weighted average between e+SVT and μ+SVT samples Statistical error is very small! Error on fs/(fu+fd) is dominated by PDG 2004
B(Ds+→+) = (3.6 ± 0.9)%
Sheldon Stone’s estimate of CLEO-c measurement (FPCP06)
B(Ds+→+) = (3.73 ± 0.42)%
![Page 48: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/48.jpg)
48
Comparison with PDG
![Page 49: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/49.jpg)
49
Comparisons with Other Results
![Page 50: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/50.jpg)
50
Outline B fragmentation overview Semileptonic signal reconstruction Semileptonic sample composition Reconstruction efficiencies Fit for fragmentation fractions Fragmentation fraction results Outlook
![Page 51: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/51.jpg)
51
Prospects New fragmentation fraction measurement
at CDF will be improved with expected new CLEO-c branching ratios
Measurements of B pT spectra at CDF in fully reconstructed modes limit uncertainty
Improved statistics are always helpful!!
![Page 52: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/52.jpg)
52
Arbor Day Poem
This is the state of man: today he puts forth
The tender leaves of hope; tomorrow blossoms,
And bears his blushing honors thick upon him;
The third day comes a frost, a killing frost;
And when he thinks, good, easy man, full surely
His greatness is a-ripening-nips his roots,
And then he falls, as I do.
--Shakespeare, Henry VIII
Excerpt taken from Indiana Division of Forestry Arbor Day website
www.in.gov/dnr/forestry/education/arborday/adpoems.html
![Page 53: Measurement of Relative Fragmentation Fractions of B Hadrons at CDF Karen Gibson Carnegie Mellon University Fermilab Wine and Cheese April 28, 2006 Arbor](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f345503460f94c52426/html5/thumbnails/53.jpg)
53
Arbor Day Poem
This is the state of man: today he puts forth
The tender leaves of hope; tomorrow blossoms,
And bears his blushing honors thick upon him;
The third day comes a frost, a killing frost;
And when he thinks, good, easy man, full surely
His greatness is a-ripening-nips his roots,
And then he falls, as I do.
--Shakespeare, Henry VIII
Excerpt taken from Indiana Division of Forestry Arbor Day website
www.in.gov/dnr/forestry/education/arborday/adpoems.html