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Observation of the Decay D^0 → K^−π^+e^+e^−

Lees, J. P. and Chao, D. S. and Cheng, C. H. and Echenard, B. and Flood, K. T. and Hitlin, D. G. and Kim, J. and Li, Y. and Miyashita, T. S. and Ongmongkolkul, P. and Porter, F. C. and Röhrken, M. (2019) Observation of the Decay D^0 → K^−π^+e^+e^−. Physical Review Letters, 122 (8). Art. No. 081802. ISSN 0031-9007.

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We report the observation of the rare charm decay D^0 → K^−π^+e^+e^−, based on 468  fb^(−1) of e^+e^− annihilation data collected at or close to the center-of-mass energy of the Υ(4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory. We find the branching fraction in the invariant mass range 0.675 < m(e^+e^−) < 0.875  GeV/c^2 of the electron-positron pair to be B(D^0 → K^−π^+e^+e^−) = (4.0±0.5±0.2±0.1)×10^(−6), where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty in the branching fraction of the decay D^0 → K^−π^+π^+π^− used as a normalization mode. The significance of the observation corresponds to 9.7 standard deviations including systematic uncertainties. This result is consistent with the recently reported D^0 → K^−π^+μ^+μ^− branching fraction, measured in the same invariant mass range, and with the value expected in the standard model. In a set of regions of m(e^+e^−), where long-distance effects are potentially small, we determine a 90% confidence level upper limit on the branching fraction B(D^0 → K^−π^+e^+e^−) < 3.1×10^(−6).

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Cheng, C. H.0000-0002-8382-0447
Hitlin, D. G.0000-0003-4028-6982
Porter, F. C.0000-0003-1948-8889
Additional Information:© 2019 Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3. Received 30 August 2018; revised manuscript received 11 December 2018; published 27 February 2019. 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), CEA and CNRS-IN2P3 (France), BMBF and DFG (Germany), INFN (Italy), FOM (Netherlands), NFR (Norway), MES (Russia), MINECO (Spain), STFC (United Kingdom), BSF (USA-Israel). Individuals have received support from the Marie Curie EIF (European Union) and the A. P. Sloan Foundation (USA).
Funding AgencyGrant Number
Department of Energy (DOE)UNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Commissariat à l’Energie Atomique (CEA)UNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Institut National de Physique Nucléaire et de Physique des Particules (IN2P3)UNSPECIFIED
Bundesministerium für Bildung und Forschung (BMBF)UNSPECIFIED
Deutsche Forschungsgemeinschaft (DFG)UNSPECIFIED
Istituto Nazionale di Fisica Nucleare (INFN)UNSPECIFIED
Stichting voor Fundamenteel Onderzoek der Materie (FOM)UNSPECIFIED
Research Council of NorwayUNSPECIFIED
Ministry of Education and Science of the Russian Federation UNSPECIFIED
Ministerio de Economía, Industria y Competitividad (MINECO)UNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
Binational Science Foundation (USA-Israel)UNSPECIFIED
Marie Curie FellowshipUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Record Number:CaltechAUTHORS:20190227-140110607
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:93306
Deposited By: Tony Diaz
Deposited On:27 Feb 2019 22:19
Last Modified:27 Feb 2019 22:19

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