Search for a Dark Leptophilic Scalar in e+e- Collisions

(B a B ar Collaboration)

Research output: Contribution to journalArticlepeer-review


Many scenarios of physics beyond the standard model predict the existence of new gauge singlets, which might be substantially lighter than the weak scale. The experimental constraints on additional scalars with masses in the MeV to GeV range could be significantly weakened if they interact predominantly with leptons rather than quarks. At an e+e- collider, such a leptophilic scalar (φL) would be produced predominantly through radiation from a τ lepton. We report herein a search for e+e-→τ+τ-φL, φL→ℓ+ℓ- (ℓ=e, μ) using data collected by the BABAR experiment at SLAC. No significant signal is observed, and we set limits on the φL coupling to leptons in the range 0.04<mφL<7.0 GeV. These bounds significantly improve upon the current constraints, excluding almost entirely the parameter space favored by the observed discrepancy in the muon anomalous magnetic moment below 4 GeV at 90% confidence level.

Original languageEnglish
Article number181801
JournalPhysical Review Letters
Issue number18
StatePublished - 28 Oct 2020


FundersFunder number
A. P. Sloan Foundation
National Science Foundation
U.S. Department of Energy
Natural Sciences and Engineering Research Council of Canada
Science and Technology Facilities Council
Marie Curie
European Commission
Deutsche Forschungsgemeinschaft
Stichting voor Fundamenteel Onderzoek der Materie
United States-Israel Binational Science FoundationU.S.-Israel
United States-Israel Binational Science Foundation
Bundesministerium für Bildung und Forschung
Ministerio de Economía y Competitividad
Ministry of Education and Science of the Russian Federation
Instituto Nazionale di Fisica Nucleare
Norges Forskningsråd
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
Institut National de Physique Nucléaire et de Physique des Particules


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