A Study of Factorization and a Measurement of CP Violation

Thesis/Dissertation · Fri Dec 01 00:00:00 EST 2006

DOI:https://doi.org/10.2172/922228· OSTI ID:922228

Dahmes, Bryan ^[1]

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1. Univ. of California, Santa Barbara, CA (United States)

We report on a study of the decay $$\bar{B}$$⁰ → D*⁺ ωπ^- with the BABAR detector at the PEP-II B-factory at the Stanford Linear Accelerator Center. Based on a sample of 232 million B⁰$$\bar{B}$$⁰ decays collected between 1999 and 2004, we measure the branching fraction β}($$\bar{B}$$⁰ → D*⁺ ωπ^-) = (2.88 ± 0.21(stat.) ± 0.31(syst.)) x 10^-3. We study the invariant mass spectrum of the ωπ^- system in this decay. This spectrum is in good agreement with expectations based on factorization and the measured spectrum in τ^- → ωπ^- v_τ. We also measure the polarization of the D*⁺ as a function of the ωπ^- mass. In the mass region 1.1 to 1.9 GeV we measure the fraction of longitudinal polarization of the D*⁺ to be Γ_L/Γ = 0.654 ± 0.042(stat.) ± 0.016(syst.). This is in agreement with the expectations from heavy-quark effective theory and factorization assuming that the decay proceeds as $$\bar{B}$$⁰ → D*⁺ ρ(1450)^-, ρ(1450)^- → ωπ^-. Furthermore, we present the results on the time-dependent CP asymmetry in neutral B meson decays to the CP eigenstate J/ΨK_L. The measurements use a data sample of about 88 million Y(4S) → B$$\bar{B}$$ decays collected between 1999 and 2002 with the BABAR detector. We study events in which one neutral B meson is fully reconstructed in the J/ΨK_L final state and the other B meson is determined to be either a B⁰ or a $$\bar{B}$$⁰ from its decay products. The amplitude of the CP asymmetry, which in the Standard Model is proportional to sin 2β, is derived from the decay-time distributions in such events. We measure sin 2β = 0.723 ± 0.158(stat.) ± 0.086(syst.), which is consistent with Standard Model expectations.

• Research Organization: SLAC National Accelerator Lab., Menlo Park, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 922228
• Report Number(s): SLAC-R-888; TRN: US0801017
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
AMPLITUDES
ASYMMETRY
B MESONS
DAUGHTER PRODUCTS
DECAY
EIGENSTATES
FACTORIZATION
POLARIZATION
STANDARD MODEL
STANFORD LINEAR ACCELERATOR CENTER
Phenomenology-HEP
HEPPH