Combined limit on the production of a light gauge boson decaying into μ+μ and π+π

The KLOE-2 Collaboration

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

We searched for the μ+μ decay of a light vector gauge boson, also known as dark photon, in the e+e→μ+μγISR process by means of the Initial State Radiation (ISR) method. We used 1.93 fb−1 of data collected by the KLOE experiment at the DAΦNE ϕ-factory. No structures have been observed over the irreducible μ+μ background. A 90% CL limit on the ratio ε2/α between the dark coupling constant and the fine structure constant of 3×10−6–2×10−7 has been set in the dark photon mass region between 519 MeV and 973 MeV. This new limit has been combined with the published result obtained investigating the hypothesis of the dark photon decaying into hadrons in e+e→π+πγISR events. The combined 90% CL limit increases the sensitivity especially in the ρ–ω interference region and excludes ε2 greater than (13−2)×10−7. For dark photon masses greater than 600 MeV the combined limit is lower than 8 ×10−7 resulting more stringent than present constraints from other experiments.

Original languageEnglish
Pages (from-to)336-341
Number of pages6
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume784
DOIs
Publication statusPublished - 10 Sep 2018

Keywords

  • Dark forces
  • ee Collisions
  • Gauge vector boson
  • Upper limits
  • SEARCH
  • DETECTOR
  • DARK PHOTON
  • E(+)E(-)
  • U-GAMMA
  • e(+) e(-) Collisions
  • PHI-MESON DECAYS
  • VECTOR BOSON
  • TO-LEADING ORDER
  • KLOE EXPERIMENT
  • RADIATIVE RETURN

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