page 1 b 0 ks + quasi 2 body modes koji hara (nagoya university) ckm2006 wg4 from charmless b...
Post on 22-Dec-2015
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TRANSCRIPT
Page 2
Analyses Reviewed
• Belle K0 hep-ex/0608039 (Accepted by PRL)K0 ,f0KS hep-ex/0609006
• BaBar KS hep-ex/0607101KS hep-ex/0608051
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B0KS Analysis Procedure1. Event selection
Flavor tagging, vertex reconstruction
2. Loose Continuum suppression Based on event shape variables
3. Nsig extraction and CP fit
Fit E-Mbc-M-event shape-cosH and t Separate fits: Nsig CP fit (Belle) Nsig and CP simultaneous fit (BaBar)
Page 4
B0KS Signal Yields
535 M BB pairsNsig 118+-18
Eff. 17%
LR>0.85
LR0.85
347 M BB pairsNsig 142+-17
Eff. 23%
Page 5
B0KS tCPV result
S=+0.11+-0.46+-0.07A=-0.09+-0.29+-0.06
S=+0.62+0.25-0.30+-0.02
C=-A=-0.43+0.25-0.23+-0.03
Dominant systematic errors:
signalt ., BB BG, tag-side interference
Dominant systematic errors:
BG frac., t resol., tag-side interference
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B0K0 (Belle)
• Selected K+K- mass region |MKK-M|10MeV/c2
• K+K-K0 non-resonant contribution is estimated from the separate Dalitz analysis to be 2.75+-0.14%.
• f0K0 contribution is treated as systematic error.
• BaBar did KKK0 time-dependent Dalitz analysis.Di Marco’s talk in WG4-14-PM1
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B0KS Yields
• Fit Mbc-E-LR(event shape+cosH)LR
LR>0.5
LR0.5
Data sample: 535 M BB pairsNsig: (K+K-)Ks, Ks+- 246+-18 (K+K-)Ks, Ks00 40+-9 (KsKL)Ks, Ks+- 21+-7
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B0 K0 tCPV result S = + 0.50 0.21 0.06A = + 0.07 0.15 0.05Background
subtracted
SKs = + 0.50 0.23
AKs = + 0.11 0.16
SKL = - 0.46 0.56
AKL = - 0.15 0.38
Results for Ks KL separate fit
Dominant systematic errors:
BG frac. t resolution, tag-side interference
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B0f0Ks (Belle)
• Selected f0+- mass region
0.890<M<1.088 GeV/c2
• Other B0 KS decay background is estimated from separate fit to MDistribution
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B0f0KS tCPV result
-S = +0.18 0.23 0.11A = -0.15 0.15 0.07
Dominant systematic errors:
Ks BG (interference effect, CPV)
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B0KS (BaBar)
• Selected 0+- mass region0. 4<M<0.9 GeV/c2
• B decay BGs are estimated from MC
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B0KS tCPV result
S = +0.20 0.52 0.24C=-A = +0.64 0.41 0.20
Dominant systematic errors:
Interference, PDF uncertainties, mis-recon and fit bias
Page 16
Summary • S=(-fsin21eff) values are consi
stent with sin21 from bccs.
• BaBar Ks tCPV errors are smaller than Belle.
– Similar analysis method is used.
– Possible reason: selection, boost factor, statistical fluctuation.
• Quasi 2 body analyses has large systematic errors from B decay BG components.
– Especially in KS modes– Time-dependent Dalitz analysi
s will be necessary for improvement.