Search for Invisible Decays of a Dark Photon Produced in e^+e^− Collisions at BaBar
We search for single-photon events in 53 fb^(−1) of e^+e^− collision data collected with the BABAR detector at the PEP-II B-Factory. We look for events with a single high-energy photon and a large missing momentum and energy, consistent with production of a spin-1 particle A′ through the process e^+e^− → γA′; A′ → invisible. Such particles, referred to as "dark photons," are motivated by theories applying a U(1) gauge symmetry to dark matter. We find no evidence for such processes and set 90% confidence level upper limits on the coupling strength of A′ to e^+e^− in the mass range m_A′≤8 GeV. In particular, our limits exclude the values of the A′ coupling suggested by the dark-photon interpretation of the muon (g−2)μ anomaly, as well as a broad range of parameters for the dark-sector models.
Additional Information© 2017 American Physical Society. Received 14 February 2017; revised manuscript received 19 August 2017; published 28 September 2017. 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 the US Department of Energy and National Science Foundation, the Natural Sciences and Engineering Research Council (Canada), the Commissariat à l'Energie Atomique and Institut National de Physique Nucléaire et de Physique des Particules (France), the Bundesministerium für Bildung und Forschung and Deutsche Forschungsgemeinschaft (Germany), the Istituto Nazionale di Fisica Nucleare (Italy), the Foundation for Fundamental Research on Matter (The Netherlands), the Research Council of Norway, the Ministry of Education and Science of the Russian Federation, the Ministerio de Economía y Competitividad (Spain), the Science and Technology Facilities Council (United Kingdom), and the Binational Science Foundation (U.S.-Israel). Individuals have received support from the Marie-Curie IEF program (European Union) and the A. P. Sloan Foundation (USA). We wish to acknowledge Adrian Down, Zachary Judkins, and Jesse Reiss for initiating the study of the physics opportunities with the single-photon triggers in BABAR, Rouven Essig for stimulating discussions and for providing data for Fig. 5, and Farinaldo Queiroz for correcting a typo in Fig. 5.
Published - PhysRevLett.119.131804.pdf
Submitted - 1702.03327.pdf
Supplemental Material - epaps.pdf
Supplemental Material - limits_eps2_BaBar2017.dat
Supplemental Material - limits_eps2_BaBar2017.readme