Scientists find new clues that dark matter may be made of dark photons

Dark matter could be made of ultra-light dark photons that have warmed our universe: this is a new scenario proposed in a study recently published in Physical examination letters. This hypothesis, the authors say, is in excellent agreement with observations made by the Cosmic Origin Spectrograph (COS) aboard the Hubble Space Telescope, which takes measurements of the “cosmic web,” the intricate, tenuous network of filaments that fills the space. between galaxies.

Data collected by COS suggests that cosmic intergalactic filaments are hotter than predicted by hydrodynamic simulations of the Standard Model of structure formation.

“Since dark photons would be able to convert to low-frequency photons and heat up cosmic structures,” the scientists explain, “they might well explain experimental information.” The study was carried out by SISSA researchers in collaboration with researchers from the universities of Tel Aviv, Nottingham and New York.

“Dark photons are good candidates for dark matter”

“Dark photons are hypothetical new particles that are force vectors for a new force in the dark sector, much like the photon is the force vector for electromagnetism,” said authors James S. Bolton ( Notitngham University), Andrea Caputo (CERN and Tel Aviv University), Hongwan Liu (New York University) and Matteo Viel (SISSA) explain.

“Unlike the photon, however, they can have mass. In particular, the ultra-light dark photon – with a mass as small as twenty orders of magnitude less than that of the electron – is a good candidate for dark matter. ”

Dark photons and regular photons should also mix together like the different types of neutrinos, allowing dark matter from ultralight dark photons to convert to low-frequency photons. These photons will heat the cosmic web but, unlike other heating mechanisms, based on astrophysical processes, such as star formation and galactic winds, this heating process is more diffuse and effective even in sparsely populated regions.

The missing element

Matteo Viel explains: “Usually, cosmic filaments have been used to probe the fine-scale properties of darkness. question, whereas in this case we used data from the low redshift intergalactic medium for the first time as a calorimeter, to check whether all the heating processes known to us are sufficient to reproduce the data. We found that this is not the case: something is missing, which we model as a contribution produced by the dark photon.”

Work has identified the mass and mixing of the dark photon with the standard model photon necessary to reconcile the gap between observations and simulation; this effort could lead to further theoretical and observational investigations to explore the exciting possibility that the dark photon could be the black matter.