Solar wind test of the de Broglie-Proca's massive photon with Cluster multi-spacecraft data

TL;DR

This study uses multi-spacecraft data from the Cluster mission to test the photon mass by examining electromagnetic properties in the solar wind, setting new upper limits on photon mass with implications for fundamental physics.

Contribution

It provides the first direct upper limit on photon mass using solar wind measurements, improving constraints through multi-spacecraft magnetic field and current analysis.

Findings

Photon mass upper limit between 1.4×10⁻⁴⁹ and 3.4×10⁻⁵¹ kg

No deviations from Ampère's law observed at 1 AU

Constraints are consistent with and improve upon previous limits

Abstract

Our understanding of the universe at large and small scales relies largely on electromagnetic observations. As photons are the messengers, fundamental physics has a concern in testing their properties, including the absence of mass. We use Cluster four spacecraft data in the solar wind at 1 AU to estimate the mass upper limit for the photon. We look for deviations from Amp\`ere's law, through the curlometer technique for the computation of the magnetic field, and through the measurements of ion and electron velocities for the computation of the current. We show that the upper bound for $m_\gamma$ lies between $1.4 \times 10^{-49}$ and $3.4 \times 10^{-51}$ kg, and thereby discuss the currently accepted lower limits in the solar wind.