'Dark photons' may be what makes up dark matter - study

"Dark photons" could help explain why cosmic intergalactic filaments are hotter than predicted by the Standard Model of Physics.

 Dark matter and gas (Illustrative). (photo credit: Wikimedia Commons)
Dark matter and gas (Illustrative).
(photo credit: Wikimedia Commons)

"Dark photons" - hypothetical particles which may make up dark matter - could help explain why cosmic intergalactic filaments are hotter than predicted by the Standard Model of Physics, according to a new peer-reviewed study published in Physical Review Letters last month.

The cosmic filaments, known as the Lyman Alpha field, are studied by the Cosmic Origin Spectrograph on the Hubble Space Telescope. Observations by the spectrograph found that the filaments were hotter than simulations conducted according to the Standard Model said they should be. 

Dark photons are hypothetical particles that may form dark matter, the mysterious substance theorized to make up about 85% of the matter in the universe. Unlike regular photons, dark photons have mass, although it is extremely small, twenty orders of magnitude less than that of an electron.

The hypothetical particles may also be able to interact with regular photons, allowing the dark photons to be converted into low-frequency photons which could heat up the "cosmic web" even in areas that are not very dense.

Study co-author Matteo Viel explained in a press release that “Usually, cosmic filaments have been used to probe small scale properties of dark matter, while in this case, we have used for the first time the low redshift intergalactic medium data as a calorimeter, to check whether all the heating processes we are aware of are sufficient to reproduce the data. We found that this is not the case: there is something missing, that we model as a contribution produced by the dark photon.”

 A computer model shows one scenario for how light is spread through the early universe on vast scales (more than 50 million light years across) (credit: Andrew Pontzen/Fabio Governato) A computer model shows one scenario for how light is spread through the early universe on vast scales (more than 50 million light years across) (credit: Andrew Pontzen/Fabio Governato)

The new study, conducted by researchers from the University of Nottingham, Tel Aviv University, New York University, and the Institute for Fundamental Physics of the Universe in Trieste, provides further support for the theory that dark photons are what make up dark matter and could serve as the first observation of the effects of dark matter outside of its gravitational effects.

Other studies focused on dark matter published recently

The study comes shortly after super energetic particles were detected by Chinese and Russian neutrino observatories studying the brightest-ever recorded gamma-ray burst, known as GRB 221009A.

One theory for how the energetic particles got here is that they were converted into "axion-like particles." Axions are lightweight particles that could make up dark matter, the substance theorized to make up the majority of the universe. The particles could also account for a problematic property of quarks.

An axion-like particle could have been made from a high-energy photo affected by the strong magnetic fields around the imploding star that caused the gamma-ray burst, according to Quanta magazine. The particle would have then been converted back into a photon as it interacted with magnetic fields in our galaxy.

The study also comes as physicists at CERN use the ForwArd Search ExpeRiment (FASER) to detect thousands of neutrino collisions in the Large Hadron Collider's current run. Researchers hope to detect dark photons in the data collected by FASER, which would help show how dark matter interacts with normal atoms and other matter in the universe through nongravitational forces.