On detection of narrow angle e+e- pairs from dark photon decays

TL;DR

This paper explores the detection of dark photons via their decay into narrow-angle electron-positron pairs in a high-energy beam experiment, proposing a specialized detector setup for identifying these rare events.

Contribution

It introduces a novel experimental approach using thin-wall drift tubes to detect narrow-angle e+e- pairs from dark photon decays in a light-shining-through-a-wall setup.

Findings

Design of a detector with minimal material to identify small-angle e+e- pairs

Feasibility analysis of detecting dark photon decays with proposed setup

Potential to improve dark photon search sensitivity

Abstract

A class of models of dark sectors consider new very weak interaction between the ordinary and dark matter transmitted by U'(1) gauge bosons A' (dark photons) mixing with our photons. If such A's exist, they could be searched for in a light-shining-through-a-wall experiment with a high energy electron beam from the CERN SPS. The proposed search scheme suggests detection of the e+e- pairs produced in the A' -> e+e- decay with a very small opening angle. Coordinate chambers based on the thin-wall drift tubes with a minimal material budget and a two-hit resolution for e+ and e- tracks separated by more than 0.5 mm are considered as an option for detecting such pairs.