Physics
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Item Meaurement of CP content and time-dependent CP violation in B0 → D*+D*- decays(2008) Anderson, Jacob M.; Roberts, Douglas; Physics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation presents the measurement of the the CP-odd fraction and time-dependent CP violation parameters for the B0 → D*+D*- decay. These results are based on the full BaBar dataset of (467 ± 5) × 106 BB pairs collected at the PEP-II B factory at the Stanford Linear Accelerator Center. An angular analysis finds that the CP-odd fraction of the B0 → D*+D*- decay is R⊥ = 0.158 ± 0.028 ± 0.006, where the first uncertainty is statistical, and the second is systematic. A fit to the flavor-tagged, time-dependent, angular decay rate yields
C+ = 0.02 ± 0.12 ± 0.02
C⊥ = 0.41 ± 0.50 ± 0.08
S+ = -0.76 ± 0.16 ± 0.04
S⊥ = -1.81 ± 0.71 ± 0.16,
for the CP-odd (⊥) and CP-even (+) contributions. Constraining these two contributions to be the same results in
C = 0.047 ± 0.091 ± 0.019
S = -0.71 $plusmn; 0.16 ± 0.03.
These measurements are consistent with the Standard Model and with measurements of sin2β from B0 → (cc)K0 decays.Item Measurements of the CP Content and CP Violating Asymmetries in Neutral B Decays to Two D* Mesons with the BaBar Detector(2004-04-12) Lillard, Vincent; Roberts, Douglas; PhysicsThis dissertation presents a measurement of time-dependent CP-violating asymmetries and a measurement of the CP-odd parity fraction in the decay B0 -> D*+D*-. The measurements are derived from a data sample of 88 x 10^6 BBbar pairs collected by the BaBar detector at the PEP-II asymmetric-energy B Factory located at the Stanford Linear Accelerator Center. A one-dimensional angular analysis of the decay products measures the CP-odd fraction to be 0.063 +/- 0.055(stat) +/- 0.009(syst), indicating that the D*+D*- final state is mostly CP-even. The time-dependent CP asymmetry parameters Im(lambda_+) and |lambda_+| are determined from an analysis of the time-dependence of flavor-tagged B decays. One neutral B meson is fully reconstructed in a D*+D*- final state, while the other B is inclusively reconstructed in order to determine its flavor. The Standard Model predicts the CP asymmetry parameters Im(lambda_+) and |lambda_+| to be -sin(2beta) and 1, respectively, in the absence of penguin diagram contributions. They are determined to be 0.05 +/- 0.29(stat) +/- 0.10(syst) and 0.75 +/- 0.19(stat) +/- 0.02(syst), respectively, which corresponds to a 2.5 sigma deviation from Standard Model predictions with penguin contributions ignored.