Speaker
Description
CASPEr-Gradient searches for axion-like particles (ALP) which are a po-
tential dark matter candidate [1]. The gradient of the ALP field is predicted
to resemble a magnetic field in its coupling to nuclear spins [2]. Therefore, a
nuclear magnetic resonance (NMR) experiment is adopted to measure such a
gradient.
The NMR detection system has been commissioned for this research. We
performed a 10-hr measurement with thermally-polarized liquid methanol sam-
ple with a 25 ppm homogeneity at the 317 G leading field, which corresponds to
searching for an ALP field at 1.349 533 MHz with 34 Hz bandwidth. Noise and
ALP coupling constant exclusion are analyzed for the measurement.
References
[1] Derek F. Jackson Kimball et al. “Overview of the Cosmic Axion Spin Pre-
cession Experiment (CASPEr)”. In: Microwave Cavities and Detectors for
Axion Research. Ed. by Gianpaolo Carosi and Gray Rybka. Cham: Springer
International Publishing, 2020, pp. 105–121. isbn: 978-3-030-43761-9.
[2] Peter W. Graham and Surjeet Rajendran. “New observables for direct de-
tection of axion dark matter”. In: Phys. Rev. D 88 (3 Aug. 2013), p. 035023.
doi: 10.1103/PhysRevD.88.035023. url: https://link.aps.org/doi/
10.1103/PhysRevD.88.035023.
