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Measurement of the branching fraction, polarization, and CP asymmetries in B^0 → ρ^0ρ^0 decay, and implications for the CKM angle α

Aubert, B. and Cheng, C. H. and Doll, D. A. and Echenard, B. and Fang, F. and Hitlin, D. G. and Narsky, I. and Piatenko, T. and Porter, F. C. (2008) Measurement of the branching fraction, polarization, and CP asymmetries in B^0 → ρ^0ρ^0 decay, and implications for the CKM angle α. Physical Review D, 78 (7). Art. No. 071104. ISSN 2470-0010. doi:10.1103/PhysRevD.78.071104.

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We study B^0→ρ^0ρ^0 decays in a sample of 465×10^6 Υ(4S)→BB events collected with the BABAR detector at the PEP-II asymmetric-energy e^+e^- collider located at the Stanford Linear Accelerator Center (SLAC). We measure the branching fraction B=(0.92±0.32±0.14)×10^(-6) and longitudinal polarization fraction f_L=0.75_(-0.14)^(+0.11)±0.05, where the first uncertainty is statistical and the second is systematic. The evidence for the B^0→ρ^0ρ^0 signal has a significance of 3.1 standard deviations, including systematic uncertainties. We investigate the proper-time dependence of the longitudinal component in the decay and measure the CP-violating coefficients S_L^(00)=(0.3±0.7±0.2) and C_L^(00)=(0.2±0.8±0.3). We study the implication of these results for the unitarity triangle angle α.

Item Type:Article
Related URLs:
URLURL TypeDescription
Cheng, C. H.0000-0002-8382-0447
Hitlin, D. G.0000-0003-4028-6982
Porter, F. C.0000-0003-1948-8889
Additional Information:© 2008 The American Physical Society. Received 30 July 2008; published 23 October 2008. We are grateful for the excellent luminosity and machine conditions provided by our PEP-II colleagues, and for the substantial dedicated effort from the computing organizations that support BABAR. The collaborating institutions wish to thank SLAC for its support and kind hospitality. This work is supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF and DFG (Germany), INFN (Italy), FOM (The Netherlands), NFR (Norway), MIST (Russia), MEC (Spain), and PPARC (United Kingdom). Individuals have received support from the Marie Curie EIF (European Union) and the A. P. Sloan Foundation.
Funding AgencyGrant Number
Department of EnergyUNSPECIFIED
Natural Sciences and Engineering Research Council (Canada)UNSPECIFIED
Institute of High Energy Physics (China)UNSPECIFIED
Commissariat à l'Énergie Atomique (French Atomic Energy Commission)UNSPECIFIED
Centre National de la Recherche Scientifique (National Center for Scientific Research, France) Institut National de Physique Nucléaire et Physique des Particules (France)UNSPECIFIED
Bundesministerium für Bildung und Forschung (German: Federal Ministry of Education and Research; Bonn, Germany)UNSPECIFIED
Deutsche Forschungsgemeinschaft (German Research Council)UNSPECIFIED
Istituto Nazionale di Fisica Nucleare, ItalyUNSPECIFIED
Foundation for Fundamental Research on Matter (The Netherlands)UNSPECIFIED
Research Council of NorwayUNSPECIFIED
Ministerio de Educación y Ciencia (Spain: Ministry for Education and Science)UNSPECIFIED
Particle Physics and Astronomy Research Council (UK)UNSPECIFIED
Marie Curie EIF (European Union)UNSPECIFIED
A. P. Sloan FoundationUNSPECIFIED
Issue or Number:7
Classification Code:PACS: 13.25.Hw, 11.30.Er, 12.15.Hh
Record Number:CaltechAUTHORS:20100623-073557014
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:18769
Deposited By: Ruth Sustaita
Deposited On:23 Jun 2010 20:44
Last Modified:08 Nov 2021 23:46

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