Searching for low mass dark matter via phonon creation in superfluid He 4

Gordon Baym, D. H. Beck, Jeffrey P. Filippini, C. J. Pethick, Jessie Shelton

Research output: Contribution to journalArticlepeer-review


We consider the scattering of dark matter particles from superfluid liquid He4, which has been proposed as a target for their direct detection. Focusing on dark matter masses below ∼1 MeV, we demonstrate from sum-rule arguments the importance of the production of single phonons with energies ω 1 meV. We show further that the anomalous dispersion of phonons in liquid He4 at low pressures [i.e., d2ω(q)/dq2>0, where q and ω(q) are the phonon momentum and energy] has the important consequence that a single phonon will decay over a relatively short distance into a shower of lower-energy phonons centered on the direction of the original phonon. Thus, the experimental challenge in this regime is to detect a shower of low-energy phonons, not just a single phonon. Additional information from the distribution of phonons in such a shower could enhance the determination of the dark matter mass.

Original languageEnglish (US)
Article number035014
JournalPhysical Review D
Issue number3
StatePublished - Aug 1 2020

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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