Search for an interaction mediated by axion-like particles with ultracold neutrons at the PSI
Journal
New Journal of Physics
Journal Volume
25
Journal Issue
10
Start Page
103012
ISSN
1367-2630
Date Issued
2023-10-01
Author(s)
Abstract
We report on a search for a new, short-range, spin-dependent interaction using a modified version of the experimental apparatus used to measure the permanent neutron electric dipole moment at the Paul Scherrer Institute. This interaction, which could be mediated by axion-like particles, concerned the unpolarized nucleons (protons and neutrons) near the material surfaces of the apparatus and polarized ultracold neutrons stored in vacuum. The dominant systematic uncertainty resulting from magnetic-field gradients was controlled to an unprecedented level of approximately 4 pT cm−1 using an array of optically-pumped cesium vapor magnetometers and magnetic-field maps independently recorded using a dedicated measurement device. No signature of a theoretically predicted new interaction was found, and we set a new limit on the product of the scalar and the pseudoscalar couplings g s g p λ 2 < 8.3 × 10 − 28 m2 (95% C.L.) in a range of 5 µm < λ < 25 mm for the monopole-dipole interaction. This new result confirms and improves our previous limit by a factor of 2.7 and provides the current tightest limit obtained with free neutrons.
Subjects
axion
axion-like particle
beyond Standard Model physics
dark matter
SDGs
Publisher
IOP Publishing
Type
journal article