f3 Impact from CLEOc Using CPTagged DKS,Lpp Decays Eric White University of Illinois Qing He Univers

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?/f3 Impact from CLEO-c UsingCP-Tagged D?KS,Lpp
DecaysEric White - University of IllinoisQing
He - University of Rochesterfor the CLEO
CollaborationCharm 07
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Path to Measuring ?/f3
Introduction Data KL-KS Binned
Analysis Conclusion

• Use B?DK decays, followed by Dalitz plot
  analysis of D?Kspp -.
• Developed by Giri, Grossman, Soffer, Zupan
  (GGSZ)1 / Belle 2 -- exploit interference
  between D0 and D0 channels

favored path VcbVus
D0K-
fD
B-
(KSpp)K-
suppressed path VcsVub
fD
D0K-
KSpp Dalitz Plot
Additional unknowns due to D0-D0 interference
N fD2 rB2fD2 2fDfDrB
cos(?D)sin(?B-? ) sin(?D)cos(?B-? )
5 parameters rB, dB, ?, cos(?D), sin(?D)
Measure at CLEO-c
1 Giri et al. Phys. Rev. D 68, 054018 (2003)
2 A.Bondar, Proceedings of Belle Special
Analysis Meeting on Dalitz Analysis, 24-26 Sept.
2002, BINP, Novosibirsk (unpub.
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Current ?/f3 Measurements
Introduction Data KL-KS Binned
Analysis Conclusion
BaBar 92o 41o(stat) 11o(syst)
12o(model) (211 fb-1)
BaBar Collaboration, B. Aubert et al.
hep-ex/0607104
Belle 53o 17o(stat) 3o(syst)
9o(model) (357 fb-1)
Belle Collaboration, A. Poluektov et al. Phys.
Rev. D73 (2006)
Statistical uncertainty will go down to about
6o with projected 2 ab-1 (rB 0.16)
(LHCb projects 3o-5o uncertainty after 5 years
)
10o model uncertainty will dominate ? CLEO-c can
help lower this number
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Measuring ci with CP-tagged KSpp Dalitz Plots
Introduction Data KL-KS Binned
Analysis Conclusion
Correlated DD pairs (C -1) are produced at
CLEO-c
?(3770)
We tag the KSpp sample by reconstructing D?CP
eigentstates
D0 D0 v2
D D
DCP
KS,Lpp
CP Tag
For CP-tagged Dalitz plots, number of events in
Dalitz plot is
M fD2 fD2 2fDfD cos(?D)
Binned Dalitz plot
Divide the (KS??)D Dalitz plot in to bins,
symmetric under interchange of p ? p
interchange.
i
Define ? ci ltcos(dD)gti
-i
ci can be determined by counting CP-tagged bins
CP-tagged flavor-tagged
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Tagged KSpp Data from CLEO-c
Introduction Data KL-KS Binned
Analysis Conclusion
We use 398 pb-1 of correlated ?(3770)?DD decays
Flavor-tagging modes D0?K-p, K-pp0, K-pp-p
(plus charge-conjugate)
Mode KK- pp- KSp0 KS?
Yield 61 33 108 29
Only two-body CP tags are used provide clean
signal with very little background
Event selection cuts ?E lt 30 (MeV) KS mass lt
3s Mbc - MD lt 4.2 (MeV) (Mbc v((Ebeam)2
(pD)2)
CP tags KK- pp-
CP- tags KSp0 KS?
Very low background
CP Tagged Data
CP- Tagged Data
Flavor Tagged Data
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What about KLpp?
Introduction Data KL-KS Binned
Analysis Conclusion

• Why not use KLpp?
• Similar structure, opposite CP
• More than doubles overall statistics

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Tagged KLpp - Data
Introduction Data KL-KS Binned
Analysis Conclusion
Use same flavor and CP tag modes as KSpp, with
same basic event selection
Mode KK- pp- KSp0 KS?
Yield 194 90 263 21
Same two-body CP tags are used as KSpp
KLpp events are reconstructed using missing
mass technique
CP tags KK- pp-
CP- tags KSp0 KS?
Require additional p0, ? veto
CP Tagged Data
CP- Tagged Data
Flavor Tagged Data
mK2 0.247
mK2 (GeV)2
mK2 (GeV)2
mK2 (GeV)2
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KLp0 vs. KSpp
Introduction Data KL-KS Binned
Analysis Conclusion
Additionally, we use KLp0 as CP-even tag for KSpp
mode

• Similar event selection, with additional cuts
• Require zero tracks
• 3s cut on p0 mass
• Additional p0s vetoed
• Reconstruct missing mass of KL

Yield 190 events
KLp0 Tagged Data
Doubles number of CP-even tags
This mode contains highest background level 5
mK2 (GeV)2
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CP-tagged KSpp - Dalitz Plots
Introduction Data KL-KS Binned
Analysis Conclusion
KS?
KS?0 resonance enhanced in CP-odd Dalitz plot
CP-odd KS?0 resonance absent in CP-even Dalitz
plot
M2(KSp)
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CP-tagged KLpp - Dalitz Plots
Introduction Data KL-KS Binned
Analysis Conclusion
Since CP of KL is opposite to KS, KLpp Dalitz
plot contains opposite CP structure to that of
KSpp
KL?
KL?0 resonance enhanced in CP-even Dalitz plot
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Flavor-tagged KS,Lpp - Dalitz Plots
Introduction Data KL-KS Binned
Analysis Conclusion
The KS,Lpp Dalitz plots are not exactly equal
There is a clear difference in the DCS K peak
M2(KSp-)
Appears constructively in KLpp, and destructively
in KSpp
M2(KSp)
Must take this into account before combining ci
measurements for KLpp and KSpp samples
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Combining ci from KSpp and KLpp
Introduction Data KL-KS Binned
Analysis Conclusion
KS and KL can be expressed
CF
DCS
Define r as the magnitude of DCS/CF ratio
r is small ( 0.06), but is the phase known?
A(D0?KSpp) K-(CF) K(DCS) f0 ?0
A(D0?KLpp) K-(CF) - K(DCS) (1-2rei?)f0
(1-2rei?)?0
Value of ci is in general different for KLpp and
KSpp, but can be related through U-spin symmetry
By varying each unknown phase and recalculating
ci , we can determine a measure of the systematic
uncertainty for KLpp
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Binned Analysis
Introduction Data KL-KS Binned
Analysis Conclusion
si can be determined from ci ?
si v1 ci2
Provided fluctuations of phase difference dD
across bins are small
m-2
Variation of dD phase can be minimized by
choosing a more intelligent, model-inspired
binning
We use N 8 bins in this analysis
?dD p
?dD 0
Bondar, Poluektov hep-ph/0703267v1 (2007)
m2
Belle Collaboration, A. Poluektov et al. Phys.
Rev. D73, 112009 (2006)
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Comparing ci for KS,Lpp -
Introduction Data KL-KS Binned
Analysis Conclusion
ci calculated from model

• Obtain KLpp model by changing sign of DCS terms ?
  K(892), K(1410)
• Calculate ci from KSpp and KLpp models
• Vary phase for each resonance, keep largest
  difference in ci

KSpp
KLpp
ci difference
model

• Systematic uncertainty from KLpp is small
  compared to ci difference
• Good agreement of ci difference in data

398 pb-1
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Sensitivity to ci
Introduction Data KL-KS Binned
Analysis Conclusion

• We combine KLpp, KSpp Dalitz plots into an
  improved overall measurement of ci
• Scale statistical uncertainty up to full 750 pb-1
• Combine with KLpp systematic uncertainty to
  determine overall expected sensitivity from
• CLEO-c measurement

ci calculated from model
Error bars represent expected uncertainty, as
projected from current data sample
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Conclusion
Introduction Data KL-KS Binned
Analysis Conclusion

• KLpp, KSpp samples can be combined
• Good sensitivity to ci
• Total DCP expected to be 1,530 for 750 pb-1
• Combined BaBar/Belle (2 ab-1) statistical
  uncertainty ? 6o
• CLEO-c can reduce model uncertainty from 10o
  down to 4o in ?/f3 measurement

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Back up
Following modes will also be used to measure ci
and si

KSpp vs. KSpp ( 480) KSpp vs. KLpp ( 1240)
Expected yields (750 pb-1)