Abstract
Positrons beam dump experiments have unique features to search for very narrow resonances coupled superweakly to pairs. Due to the continued loss of energy from soft photon bremsstrahlung, in the first few radiation lengths of the dump a positron beam can continuously scan for resonant production of new resonances via annihilation off an atomic in the target. In the case of a dark photon kinetically mixed with the photon, this production mode is of first order in the electromagnetic coupling , and thus parametrically enhanced with respect to the production mode and to the bremsstrahlung in -nucleon scattering so far considered. If the lifetime is sufficiently long to allow the to exit the dump, decays could be easily detected and distinguished from backgrounds. We explore the foreseeable sensitivity of the Frascati PADME experiment in searching with this technique for the 17 MeV dark photon invoked to explain the anomaly in nuclear transitions.
- Received 2 March 2018
DOI:https://doi.org/10.1103/PhysRevD.97.095004
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.
Published by the American Physical Society