Stochastic properties of ultralight scalar field gradients

Journal Article · 24 September 2021 · Physical Review. D.

DOI: https://doi.org/10.1103/physrevd.104.055037 · OSTI ID:1851046

Lisanti, Mariangela ^[1]; Moschella, Matthew ^[2]; Terrano, William ^[2]

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1. Princeton Univ., NJ (United States); OSTI
2. Princeton Univ., NJ (United States)

Ultralight axion-like particles are well-motivated dark matter candidates that are the target of numerous direct detection efforts. In the vicinity of the Solar System, such particles can be treated as oscillating scalar fields. The velocity dispersion of the Milky Way determines a coherence time of about 10⁶ oscillations, beyond which the amplitude of the axion field fluctuates stochastically. Any analysis of data from an axion direct detection experiment must carefully account for this stochastic behavior to properly interpret the results. This is especially true for experiments sensitive to the gradient of the axion field that are unable to collect data for many coherence times. Indeed, the direction, in addition to the amplitude, of the axion field gradient fluctuates stochastically. We present the first complete stochastic treatment for the gradient of the axion field, including multiple computationally efficient methods for performing likelihood-based data analysis, which can be applied to any axion signal, regardless of coherence time. Additionally, we demonstrate that ignoring the stochastic behavior of the gradient of the axion field can potentially result in failure to discover a true axion signal

• Research Organization: Princeton University, NJ (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: SC0007968
• OSTI ID: 1851046
• Journal Information: Physical Review. D., Journal Name: Physical Review. D. Journal Issue: 5 Vol. 104; ISSN 2470-0010
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English