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Averages of B-Hadron Properties at the End of 2005
This article reports world averages for measurements on b-hadron properties obtained by the Heavy Flavor Averaging Group (HFAG) using the available results as of at the end of 2005. In the averaging, the input parameters used in the various analyses are adjusted (rescaled) to common values, and all known correlations are taken into account. The averages include lifetimes, neutral meson mixing parameters, parameters of semileptonic decays, branching fractions of B decays to final states with open charm, charmonium and no charm, and measurements related to CP asymmetries
Observation of CP violation in the B0 meson system
We present an updated measurement of time-dependent CP-violating asymmetries
in neutral B decays with the BABAR detector at the PEP-II asymmetric B Factory
at SLAC. This result uses an additional sample of Upsilon(4S) decays collected
in 2001, bringing the data available to 32 million B-anti-B pairs. We select
events in which one neutral B meson is fully reconstructed in a final state
containing charmonium and the flavor of the other neutral B meson is determined
from its decay products. The amplitude of the CP-violating asymmetry, which in
the Standard Model is proportional to sin2beta, is derived from the decay time
distributions in such events. The result sin2beta = 0.59 +/- 0.14 (stat) +/-
0.05 (syst) establishes CP violation in the B^0 meson system. We also determine
|lambda| = 0.93 +/- 0.09 {stat} +/- 0.03 {syst}, consistent with no direct CP
violation.Comment: 8 pages, 2 figures, submitted to Physical Review Letter
Measurement of the CP violating asymmetry amplitude sin 2beta
We present results on time-dependent CP-violating asymmetries in neutral B
decays to several CP eigenstates. The measurements use a data sample of about
88 million Y(4S) --> B Bbar decays collected between 1999 and 2002 with the
BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We study
events in which one neutral B meson is fully reconstructed in a final state
containing a charmonium meson and the other B meson is determined to be either
a B0 or B0bar from its decay products. The amplitude of the CP-violating
asymmetry, which in the Standard Model is proportional to sin2beta, is derived
from the decay-time distributions in such events. We measure sin2beta = 0.741
+/- 0.067 (stat) +/- 0.034 (syst) and |lambda| = 0.948 +/- 0.051 (stat) +/-
0.030 (syst). The magnitude of lambda is consistent with unity, in agreement
with the Standard Model expectation of no direct CP violation in these modes.Comment: 7 pages, 2 postscript figures, submitted to PR