$A'$ view of the sunrise: Boosting helioscopes with angular information

TL;DR

This paper enhances helioscope sensitivity to solar dark photons by incorporating their angular and spectral distributions, significantly improving constraints on dark photon properties through analysis of solar and eclipse data.

Contribution

It introduces a novel approach that uses angular and spectral information of dark photons to improve helioscope sensitivity, applying this to real solar and eclipse data for the first time.

Findings

Boosted constraints on dark photon mixing parameters by over an order of magnitude.

Demonstrated the importance of angular and spectral features in dark photon detection.

Applied the method to existing solar and eclipse data, enhancing sensitivity.

Abstract

The Sun may copiously produce hypothetical light particles such as axions or dark photons, a scenario which can be experimentally probed with so-called helioscopes. Here we investigate the impact of the angular and spectral distribution of solar dark photons on the sensitivity of such instruments. For the first time we evaluate this spectral and angular dependence of the dark photon flux over the whole mass range and apply this information to existing data from the Hinode Solar X-Ray Telescope. Specifically we use calibration images for a classical helioscope analysis as well as data from a solar eclipse providing sensitivity to exceptionally large oscillation lengths. We demonstrate that exploiting the signal features can boost the constraints by more than one order of magnitude in terms of the mixing parameter compared to a naive counting experiment.