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Results on Time-Dependent CP Measurements: Winter 2003 (FPCP 2003, Paris)

We present averages for Legend: if not stated otherwise, We use Combos v3.20 (homepage, manual) for the rescaling of the experimental results to a common set of input parameters.

021003

Time-dependent CP Asymmetries in b → cc-bar s and b → qq-bar s (penguin)

The experimental results have been rescaled to a common set of input parameters (see table below). Both, BABAR and Belle use the PDG 2002 values for the neutral B lifetime and oscillation frequency in their time-dependent likelihood fits.

Parameter Value Ref. / Comments
τ(Bd) (1.539 ± 0.014) ps LEP B lifetime WG (Moriond'03)
Δmd (0.502 ± 0.006) ps–1 LEP B lifetime WG (Moriond'03)
|A^| 2 0.160 ± 0.032 ± 0.014 BABAR, Phys.Rev.Lett. 87 (2001) 241801
0.19 ± 0.02 ± 0.03 Belle, Phys. Lett. B538 (2002) 11-20
0.179 ± 0.030 Average used for rescaling

We obtain for sin(2β/φ1) in the different decay modes:
(we have added correlated systematics of 0.008 for the uncertainty on tag side CP asymmetries for Doubly-Cabibbo-suppressed B decays to all Belle numbers, and to BABAR's numbers in the s penguin modes - see Ref. hep-ex/0303030 )

Parameter: sin(2β/φ1) = S (if β/φ1 dominant weak phase)
Mode(s) BABAR Belle Average Ref. / Comments
J/ψKS, ψ(2S)KS, χc1KS, ηCKS 0.76 ± 0.07stat 0.71 ± 0.09stat - BABAR'02: Phys.Rev.Lett. 89 (2002) 201802

Belle: Phys.Rev. D66 (2002) 071102
J/ψKL (ηCP=–1) 0.72 ± 0.16stat 0.78 ± 0.17stat
J/ψK*0 (K*0 → KSπ0 0.22 ± 0.52stat 0.04 ± 0.63stat
All charmonium 0.741 ± 0.067 ± 0.034 0.719 ± 0.074 ± 0.035 0.731 ± 0.056
(0.050stat-only)		 CL = 0.84
ΦKS –0.18 ± 0.51 ± 0.07 –0.73 ± 0.64 ± 0.22 –0.38 ± 0.41
(0.40stat-only)
CL=0.52		 BABAR preliminary (Moriond'03)

BABAR: hep-ex/0303046 (2003) (submitted to PRL)

Belle: Phys.Rev. D67 (2003) 031102
η'KS 0.02 ± 0.34 ± 0.03 0.71 ± 0.37 +0.05–0.06 0.33 ± 0.25
(0.25stat-only)
CL=0.17
K+K–KS not yet available 0.49 ± 0.43 ± 0.11 +0.33–0.00 0.49 ± 0.43 ± 0.11 +0.33–0.00
All b → s penguin 0.19 ± 0.20 (0.19stat-only) CL = 0.26
All modes 0.695 ± 0.054 (0.48stat-only) CL = 0.06

Note that

Including the earlier sin(2β/φ1) measurements using Bd → J/ψKS decays:

Parameter: sin(2β/φ1)
Experiment Value Ref. / Comments
ALEPH 0.84 +0.82–1.04 ± 0.16 Phys.Lett. B492 (2000) 259-274
OPAL 3.2 +1.8–2.0 ± 0.5 Eur.Phys.J. C5 (1998) 379-388
CDF 0.79 +0.41–0.44(stat+syst) Phys.Rev. D61 (2000) 072005

we find the only slightly modified averages:

Parameter: sin(2β/φ1)
All charmonium 0.734 ± 0.055
All modes 0.699 ± 0.054


   Compilation of results for sin(2β/φ1)   
eps gif gif(high res)
eps gif gif(high res)
eps gif gif(high res)

The cosine coefficient: the experiments determine |λ| for the charmonium modes and C = –A = (1–|λ|2)/(1+|λ|2) for the penguin modes. We recompute C from |λ| for the following averages.

Parameter: C=–A (if not stated otherwise)
Mode(s) BABAR Belle Average Ref. / Comments
Charmonium |λ| = 0.948 ± 0.051 ± 0.030 0.950 ± 0.049 ± 0.034
(added DCSD systematics) 		0.949 ± 0.045
(0.035stat-only)
CL = 0.98
 BABAR'02: Phys.Rev.Lett. 89 (2002) 201802

Belle: Phys.Rev. D66 (2002) 071102
C = 0.053 +0.055–0.052 +0.032–0.031 0.051 +0.053–0.050 +0.035–0.036
(added DCSD systematics) 		0.052 +0.048–0.046 (0.037stat-only)
CL = 0.98
ΦKS –0.80 ± 0.38 ± 0.12 0.56 ± 0.41 ± 0.16
(added DCSD systematics)		 –0.19 ± 0.30
CL=0.02		 BABAR preliminary (Moriond'03)

BABAR: hep-ex/0303046 (2003) (submitted to PRL)

Belle: Phys.Rev. D67 (2003) 031102
η'KS 0.10 ± 0.22 ± 0.03
(added DCSD systematics)		 –0.26 ± 0.22 ± 0.04
(added DCSD systematics)		 –0.08 ± 0.16
CL=0.25
K+K–KS not yet available 0.40 ± 0.33 ± 0.10+0.26–0.00
(added DCSD systematics)		 0.40 ± 0.33 ± 0.10+0.26–0.00
All b → s penguin –0.04 ± 0.13 (0.13stat-only) CL = 0.08
All modes 0.045 ± 0.047 (0.035stat-only) CL = 0.18

Time-dependent CP Asymmetries in b → cc-bar d (D(*)+D(*)–, J/ψ π0)

Due to possible significant penguin pollution both, the cosine and the sine coefficients of the Cabibbo-suppressed b → cc-bar d decays are free parameters of the theory. Absence of penguin pollution would signify Scc-bar d=–sin(2β/φ1) and Ccc-bar d=0.

At present we do not apply a rescaling of the results to a common, updated set of input parameters. Both, BABAR and Belle use the PDG 2002 values for the neutral B lifetime and oscillation frequency in their time-dependent likelihood fits.

Experiment SJ/ψπ0 CJ/ψπ0 = –AJ/ψπ0 Correlation Ref. / Comments
BABAR'02
N(BB)=88m 		0.05 ± 0.49 ± 0.16 0.38 ± 0.41 ± 0.09 –0.12 hep-ex/0207058 (2002) preliminary
Belle'03
N(BB)=85m 		–0.93 ± 0.49 ± 0.08 0.25 ± 0.39 ± 0.06 –0.23 hep-ex/0207098 (2002) preliminary
Average
(preliminary)		 –0.47 ± 0.36 0.26 ± 0.29 –0.12 χ2 = 2.0 (CL = 0.37 → 0.90σ)
Figures:
eps gif gif (high res)
eps gif gif (high res)		 nothing

We convert Im(λ) = S/(1 + C) and |λ|2 = (1 - C)/(1 + C), taking into account correlations:

Experiment SD*+D*– CD*+D*– Correlation Ref. / Comments
BABAR'02
N(BB)=88m 		Im(λ) = 0.31 ± 0.43 ± 0.13 |λ| = 0.98 ± 0.25 ± 0.09 0.18 hep-ex/0207072 (2002) preliminary
Mode found to be mostly CP-even
S = 0.32 ± 0.43 ± 0.13 C = 0.02 ± 0.25 ± 0.09 0.00
Belle not yet available

Experiment S+–(D*+D–) C+–(D*+D–) S–+(D*–D+) C–+(D*–D+) Ref. / Comments
BABAR'03
N(BB)=89m 		–0.82 ± 0.75 ± 0.14 –0.47 ± 0.40 ± 0.12 –0.24 ± 0.69 ± 0.12 –0.22 ± 0.37 ± 0.10 BABAR preliminary (Moriond'03)
Belle not yet available


021003

Time-dependent CP Asymmetries in Bd→ π+π–

At present we do not apply a rescaling of the results to a common, updated set of input parameters. Both, BABAR and Belle use the PDG 2002 values for the neutral B lifetime and oscillation frequency in their time-dependent likelihood fits. Common systematics due to these and other correlated uncertainties are thus neglected in the following average.

Experiment Sππ Cππ = –Aππ Correlation Ref. / Comments
BABAR'02
N(BB)=88m 		0.02 ± 0.34 ± 0.05 –0.30 ± 0.25 ± 0.04 –0.10 Phys.Rev.Lett. 89 (2002) 281802
Belle'03
N(BB)=85m 		–1.23 ± 0.41 +0.08–0.07 –0.77 ± 0.27 ± 0.08 –0.024 hep-ex/0301032 (2003)
Average –0.47 ± 0.26 –0.49 ± 0.19 0.068 χ2 = 7.05 (CL = 0.029 → 2.18σ)
Figures:
eps gif gif (high res)
eps gif gif (high res)		 nothing


The Penguin-to-tree ratio: using as input the measured Cππ and Sππ coefficients together with the Wolfenstein parameters ρ and η from the Global CKM fit using standard constraints, one can infer module and phase of the complex penguin to tree (P/T) ratio in Bd→ π+π– decays within the Standard Model. Note that the definition of P/T is convention-dependent (see, e.g., GroRo02). We choose to eliminate the top quark in the penguin loop using CKM unitarity, so that the amplitudes can be parameterized as follows:
A(Bd→ π+π–)  =  Ru ei γ T + RcP
A(Bd-bar→ π+π–)  =  Ru e–i γ T + RcP
where (Ru/Rc)2 ≈ ρ2 + η2 measures one side of the unitarity triangle and γ=arctan(η/ρ) determines its inclination angle wrt the real axis.
eps gif gif (high res)


Time-dependent CP Asymmetries in Bd→ ρ+π–

At present we do not apply a rescaling of the results due to the fit dependence on the Bd lifetime and oscillation frequency. BABAR uses the PDG 2002 values for the neutral B lifetime and oscillation frequency in their time-dependent likelihood fit.

Experiment ACP(ρπ) Sρπ Cρπ ΔSρπ ΔCρπ Correlations Ref. / Comments
BABAR'02
N(BB)=89m		 –0.18 ± 0.08 ± 0.03 0.19 ± 0.24 ± 0.03 0.36 ± 0.18 ± 0.04 0.15 ± 0.25 ± 0.03 0.28 ± 0.19 ± 0.04 Table BABAR preliminary (Moriond'03)
Belle not yet available

This page is maintained by Andreas Höcker and was last updated on April 5, 2003