Freiburg 2024 – scientific programme

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A: Fachverband Atomphysik

A 25: Poster IV

A 25.21: Poster

Wednesday, March 13, 2024, 17:00–19:00, Tent A

Towards measurements of axionic Dark Matter with the CASPEr-gradient low-field experiment — •Julian Walter and Yuzhe Zhang for the CASPEr collaboration — Helmholtz-Institut, GSI Helmholtzzentrum fuer Schwerionenforschung, 55128 Mainz, Germany

Axions and other light pseudoscalar bosons (< 1 eV/c²) which are collectively referred to as axion-like particles (ALPs) have become well-motivated dark matter candidates. The Cosmic Axion Spin Precession Experiment (CASPEr) [1] aims at detecting ALPs with nuclear magnetic resonance techniques. CASPEr-Gradient in Mainz probes the hypothetic coupling of nuclear spins to the gradient of the ALP field [2]. The experimental apparatus was designed to scan ALPs with Compton frequencies of up to 600 MHz, corresponding to a mass range of approximately up to 10⁻⁶ eV. We performed a test measurement on a thermally polarized liquid methanol sample at a 317 G leading field, which corresponds to searching for ALP fields at 1.348568 MHz within a 238-Hz bandwidth. The data analysis strategy and preliminary results are presented.

[1] D. F. J. Kimball et al. "Overview of the Cosmic Axion Spin Precession Experiment (CASPEr)". In: Microwave Cavities and Detectors for Axion Research. Cham: Springer International Publishing, 2020, pp. 105-121. ISBN: 978-3-030-43761-9

[2] P. W. Graham and S. Rajendran. "New observables for direct detection of axion dark matter". In: Phys. Rev. D 88 (3 Aug. 2013), p. 035023. DOI: 10.1103/PhysRevD.88.035023.

Keywords: Dark Matter; Axion-like Particle; Axion; Nuclear Magnetic Resonance