CP Asymmetry in semileptonic B decays
This web page summarizes the results for the measurement
of CP asymmetry for same-sign dimuons from B decays with 1.6 fb^{-1} of
data. Corrections to the raw asymmetry are made for contributions from the detector, trigger, and hadrons from B decays which are reconstructed
as muons.
The results have been approved as of October 18, 2007.
A summary of this analysis and results can be found in this public note.
Using a dedicated dimuon trigger, we isolate a sample of 660k opposite
sign and 440k same sign dimuon pairs. We use impact parameter information
of the two muons to separate the b-bbar component of the sample from
components arising from prompt and charm sources. After extracting the
b-bbar fraction, we correct for hadrons faking muons as well as
detector and trigger asymmetries.
We measure:
- A_{SL} = 0.0080 ± 0.0090 (stat) ± 0.0068 (syst)
Under the assumption that the CP asymmetry in charged B and b-baryon decays is negligible, we then correct for the measured semileptonic CP asymmetry in B^{0} decays (as measured at Babar and Belle) and extract the CP asymmetry for semileptonic B_{s} decays:
- A^{s}_{SL}= 0.020 ± 0.021 (stat) ± 0.016 (syst) ± 0.009 (inputs)
A^{s}_{SL} is calculated using our measurement of A_{SL}, HFAG 2007 world average (f_{s}Z_{s})
/(f_{d}Z_{d}), and the average value of A^{d}_{SL} measured by the B factories.)
Below are the eps versions of figures meant for downloads.
- Figure 1: Combined 3D impact parameter distribution (.eps)
- Figure 2: &mu^{+}&mu^{-} impact parameter distribution (.eps)
- Figure 3: &mu^{+}&mu^{-} fit x-projection (log) and residual (.eps)(.eps)
- Figure 4: &mu^{+}&mu^{-} fit y-projection and residual (.eps)(.eps)
- Figure 5: &mu^{+}&mu^{+} impact parameter distribution (.eps)
- Figure 6: &mu^{+}&mu^{+} fit x-projection (log) and residual (.eps)(.eps)
- Figure 7: &mu^{+}&mu^{+} fit y-projection and residual (.eps)(.eps)
- Figure 8: &mu^{-}&mu^{-} impact parameter distribution (.eps)
- Figure 9: &mu^{-}&mu^{-} fit x-projection (log) and residual (.eps)(.eps)
- Figure 10: &mu^{-}&mu^{-} fit y-projection and residual (.eps)(.eps)
- Figure 11: &Upsilon dimuon impact parameter distribution (.eps)
- Figure 12: &Upsilon mass distribution (.eps)
- Figure 13: D^{0} mass distribution (for K^{+}) (.eps)
- Figure 14: D^{0} mass distribution (for K^{-}) (.eps)
- Figure 15: D^{0} mass distribution (for &pi^{+}) (.eps)
- Figure 16: D^{0} mass distribution (for &pi^{-}) (.eps)
- Figure 17: D^{0} mass distribution (for K^{+} faking &mu) (.eps)
- Figure 18: D^{0} mass distribution (for K^{-} faking &mu) (.eps)
- Figure 19: D^{0} mass distribution (for &pi^{+} faking &mu) (.eps)
- Figure 20: D^{0} mass distribution (for &pi^{-} faking &mu) (.eps)
- Figure 21: D^{*} - D^{0} mass difference (.eps)