An Updated Measurement of the CP Violating Phase βsJ/ψ &phi
This webpage summarizes the blessed result updating the flavor-tagged determination of
CP violation in Bs &rarr J/&psi &phi decays corresponding
to 2.8 fb-1 data.
This result is described in this
public note
See also the previous result at
First Flavor-Tagged Determination of Bounds on CP Violation in Bs &rarr J/&psi &phi Decays
published at PRL 100, 161802 (2008)
We present 68% and 95% confidence regions
in the &betas-&Delta&Gamma plane:
Assuming the standard model predictions of &betas and delta_gamma, the
probability of a deviation as large as the level of the observed data
is 7%, corresponding to 1.8 Gaussian standard deviations.
Additionally, we present a confidence
interval of &betas, where &Delta&Gamma is treated as a nuisance
parameter, and find that &betas is within [0.28, 1.29] at the 68% CL
and within [-&pi/2, -1.45] U [-1.01, -0.57] U [-0.13, &pi/2] at 95% CL.
Assuming no CP violation (&betasJ/&psi &phi = 0), we
also measure
the mean lifetime c&taus = 459 ± 12 (stat) ± 3 (syst) μm
the width difference &Delta&Gammas = 0.02 ± 0.05 (stat) ± 0.01 (syst) ps-1
and the transversity amplitudes
|A||(0)|2 = 0.241 ± 0.019 (stat) ± 0.007 (syst)
|A0(0)|2 = 0.508 ± 0.024 (stat) ± 0.008 (syst).
Below are all figures meant for download.
- (eps),
(png): B+ invariant mass distribution.
- (eps),
(png): Bs invariant mass distribution.
- (eps),
(png): B+/- neural network training.
- (eps),
(png): Bs neural network training.
- (eps),
(png): Opposite side tag measured
vs. predicted dilution in B+ decays (1st half of data).
- (eps),
(png): Opposite side tag measured
vs. predicted dilution in B+ decays (2nd half of data).
- (eps),
(png): Opposite side tag measured
vs. predicted dilution in B- decays (1st half of data).
- (eps),
(png): Opposite side tag measured
vs. predicted dilution in B- decays (2nd half of data).
- (eps),
(png): Opposite side tag measured
vs. predicted dilution in an admixture of B+/- decays (1st half of data).
- (eps),
(png): Opposite side tag measured
vs. predicted dilution in an admixture of B+/- decays (2nd half of data).
- (eps),
(png): Phi angular distribution.
- (eps),
(png): cos(Theta) angular distribution.
- (eps),
(png): cos(Phi) angular distribution.
- (eps),
(png): 2D likelihood profile
- (eps),
(png): 2D likelihood profile comparison
with published result
- (eps),
(png): 1D likelihood profile
- (eps),
(png): Sensitivity projections
- (gif): Projected tagging improvement.
- (gif): Projected tagging cross check.
