@article{94cd14b659d941629f5f2112cf7fddf8,
title = "Combined limit on the production of a light gauge boson decaying into μ+μ− and π+π−",
abstract = "We searched for the μ+μ− decay of a light vector gauge boson, also known as dark photon, in the e+e−→μ+μ−γISR 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′/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+π−γISR 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.",
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",
author = "{The KLOE-2 Collaboration} and A. Anastasi and D. Babusci and M. Berlowski and C. Bloise and F. Bossi and P. Branchini and A. Budano and B. Cao and F. Ceradini and P. Ciambrone and F. Curciarello and E. Czerwi{\'n}ski and G. D'Agostini and E. Dan{\`e} and {De Leo}, V. and {De Lucia}, E. and {De Santis}, A. and {De Simone}, P. and {Di Cicco}, A. and {Di Domenico}, A. and D. Domenici and A. D'Uffizi and A. Fantini and G. Fantini and P. Fermani and S. Fiore and A. Gajos and P. Gauzzi and S. Giovannella and E. Graziani and Ivanov, {V. L.} and T. Johansson and X. Kang and D. Kisielewska-Kami{\'n}ska and Kozyrev, {E. A.} and W. Krzemien and A. Kupsc and Lukin, {P. A.} and G. Mandaglio and M. Martini and R. Messi and S. Miscetti and D. Moricciani and P. Moskal and A. Passeri and V. Patera and {Perez del Rio}, E. and N. Raha and P. Santangelo and Solodov, {E. P.}",
year = "2018",
month = sep,
day = "10",
doi = "10.1016/j.physletb.2018.08.012",
language = "English",
volume = "784",
pages = "336--341",
journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",
issn = "0370-2693",
publisher = "Elsevier",
}