Manley, J.Stump, R.Petery, R.Singh, S.2024-02-052024-02-052023-10-11Manley, J., R. Stump, R. Petery, and S. Singh. “Searching for Scalar Ultralight Dark Matter via Refractive Index Changes in Fibers.” Physical Review D 108, no. 7 (October 11, 2023): 075008. https://doi.org/10.1103/PhysRevD.108.075008.2470-0029https://udspace.udel.edu/handle/19716/33945This article was originally published in Physical Review D. The version of record is available at: https://doi.org/10.1103/PhysRevD.108.075008. Published by the American Physical Society under the terms ofthe Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution tothe author(s) and the published article’s title, journal citation and DOI. Funded by SCOAP3.We propose using an optical fiber-based interferometer to search for scalar ultralight dark matter (UDM) with particle mass in the range 10−17−10−13  eV/c2 (10−3−10Hz). Composed of a solid core and a hollow core fiber, the proposed detector would be sensitive to relative oscillations in the fibers’ refractive indices due to scalar UDM-induced modulations in the fine-structure constant α. We predict that, implementing detector arrays or cryogenic cooling, the proposed optical fiber-based scalar UDM search has the potential to reach new regions of the parameter space. Such a search would be particularly well-suited to probe for a solar halo of dark matter with a sensitivity exceeding that of previous dark matter searches over the particle mass range 7×10−17−2×10−14  eV/c2.en-USAttribution 4.0 InternationalArticle