Cosmic Analogues of the Stern-Gerlach Experiment and the Detection of Light Bosons

TL;DR

This paper proposes using radio pulse timing from magnetars to detect light bosons like axions, potentially surpassing current experimental sensitivities by analyzing beam-splitting effects caused by magnetic field gradients.

Contribution

It introduces a novel astrophysical method to detect light bosons through radio pulse analysis from magnetars, extending sensitivity beyond terrestrial experiments.

Findings

Potential detection of light bosons with coupling constants as low as 1e-14 1/GeV.

Radio pulse splitting increases linearly with wavelength, aiding identification.

Current data can be used to search for these effects with minimal additional observations.

Abstract

We show that, by studying the arrival times of radio pulses from highly-magnetized pulsars, it may be possible to detect light spin-0 bosons (such as axions and axion-like particles) with a much greater sensitivity, over a broad particle mass range than is currently reachable by terrestrial experiments and indirect astrophysical bounds. In particular, we study the effect of splitting of photon-boson beams under intense magnetic field gradients in magnetars and show that radio pulses (at meter wavelengths) may be split and shift by a discernible phase down to a photon-boson coupling constant of g ~ 1e-14 [1/GeV]; i.e., about four orders of magnitude lower than current upper limits on g. The effect increases linearly with photon wavelength with split pulses having equal fluxes and similar polarizations. These properties make the identification of beam-splitting and beam deflection effects straightforward with currently available data. Better understanding of radio emission from magnetars is, however, required to confidently exclude regions in the parameter space when such effects are not observed.