Search for a muonic dark force at BABAR
Many models of physics beyond the standard model predict the existence of new Abelian forces with new gauge bosons mediating interactions between "dark sectors" and the standard model. We report a search for a dark boson Z′ coupling only to the second and third generations of leptons in the reaction e+e− → μ+μ− Z′,Z′ → μ+μ− using 514 fb^(−1) of data collected by the BABAR experiment. No significant signal is observed for Z′ masses in the range 0.212–10 GeV. Limits on the coupling parameter g′ as low as 7×10^(−4) are derived, leading to improvements in the bounds compared to those previously derived from neutrino experiments.
Additional Information© 2016 American Physical Society. Received 14 June 2016; published 19 July 2016. We thank Maxim Pospelov for helpful conversations. We are grateful for the extraordinary contributions of our PEP-II2 colleagues in achieving the excellent luminosity and machine conditions that have made this work possible. The success of this project also relies critically on the expertise and dedication of the computing organizations that support BABAR. The collaborating institutions wish to thank SLAC for its support and the kind hospitality extended to them. 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, 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).
Published - PhysRevD.94.011102.pdf
Submitted - 1606.03501v1.pdf