Skip to main content

Dark-matter harmonics beyond annual modulation

Author(s): Lee, Samuel K; Lisanti, Mariangela; Safdi, Benjamin R

To refer to this page use:
Abstract: The count rate at dark-matter direct-detection experiments should modulate annually due to the motion of the Earth around the Sun. We show that higher-frequency modulations, including daily modulation, are also present and in some cases are nearly as strong as the annual modulation. These higher-order modes are particularly relevant if (i) the dark matter is light, O(10) GeV, (ii) the scattering is inelastic, or (iii) velocity substructure is present; for these cases, the higher-frequency modes are potentially observable at current and ton-scale detectors. We derive simple expressions for the harmonic modes as functions of the astrophysical and geophysical parameters describing the Earth’s orbit, using an updated expression for the Earth’s velocity that corrects a common error in the literature. For an isotropic halo velocity distribution, certain ratios of the modes are approximately constant as a function of nuclear recoil energy. Anisotropic distributions can also leave observable features in the harmonic spectrum. Consequently, the higher-order harmonic modes are a powerful tool for identifying a potential signal from interactions with the Galactic dark-matter halo.
Publication Date: Nov-2013
Electronic Publication Date: 13-Nov-2013
Citation: Lee, Samuel K, Lisanti, Mariangela, Safdi, Benjamin R. (2013). Dark-matter harmonics beyond annual modulation. JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, 10.1088/1475-7516/2013/11/033
DOI: doi:10.1088/1475-7516/2013/11/033
ISSN: 1475-7516
Type of Material: Journal Article
Version: Author's manuscript

Items in OAR@Princeton are protected by copyright, with all rights reserved, unless otherwise indicated.