A pair polarimeter for multi-GeV $\gamma$-rays
Abstract
Accessing the polarization of photon allows to understand the mechanisms behind its emission or scattering, revealing much about a peculiar environment or a probed object. For energy above 10~MeV, the pair production dominates the photon-matter interaction and the photon polarization is accessible via the azimuthal angle of the conversion. Unfortunately pair polarimeters have a low figure-of-merit for multi-GeV photons and are mostly used for beam characterization. In this paper, we report a new concept of a compact pair polarimeter associating monolithic active pixel sensors to low-density extended solid converters to reach simultaneously a high efficiency of 7\% and intrinsic analyzing power ranging from 0.2 to 0.5. This new concept will add a new obersvable to the multi-messenger physics, isolate the intrinsic strong force in nucleons and possibly reveal violations of Lorentz invariance.
Cite
@article{arxiv.2508.00022,
title = {A pair polarimeter for multi-GeV $\gamma$-rays},
author = {Maxime Defurne and Arthur Muhulet},
journal= {arXiv preprint arXiv:2508.00022},
year = {2025}
}