The Dark Photon Dark Matter Discovery: Groundbreaking Cryogenic Detection Techniques

 

April 07, 2023

Millimetre-wave technologies aid in the investigation of "light" dark matter

Kyoto University researchers have developed an experimental method for studying ultra-light dark matter by observing its gravitational effects on visible matter. Using new techniques, the team achieved experimental parameters for unexplored mass ranges of dark photon dark matter (DPDM) using millimetre-wave sensing in cryogenic conditions. Although no significant signal was detected, the experiments' stringent constraints open up possibilities for investigating dark matter. The research may also contribute to the advancement of advanced telecommunications technologies such as 5G and 6G.

There may have been more than one way to defeat Goliath in the biblical story, but David chose to attack with a small stone and a catapault.

In the same vein, scientists have approached the mystery of dark matter, which accounts for one-fourth of the universe, by recording its gravitational effects on visible matter rather than by direct observation.

A team of researchers from Kyoto University has developed an experimental method for studying ultra-light dark matter at 0.1 milli-electron volts using a millimetre-wave sensing technology with low thermal noise.

"We obtained experimental parameters for the previously unexplored mass range of dark photon dark matter (DPDM) by using previously untested techniques in this field," says lead author Shunsuke Adachi.

A single dark matter particle's elusive mass has been assumed to be heavier than that of a proton. Adachi's team's search for ultra-low-mass dark matter addresses the extremely difficult detection problem that has eluded scientists for more than three decades.

"Our research on millimetre-wave technologies may contribute to the advancement of advanced telecommunications such as 5G and 6G," Adachi adds.

To suppress thermal noise and accommodate weak conversion photons, a dedicated millimetre-wave receiver is cooled to -270 °C. This cryogenic receiver searches for DPDMs with masses in the 0.1 meV range.

Although Adachi's team did not find any significant signal in this dataset, he believes that by conducting their experiments with unprecedentedly stringent constraints—tighter than cosmological constraints—they opened up new avenues for investigating dark matter.

Using metal plate surfaces, ordinary photons are theoretically converted from dark photons. Because of energy conservation, these conversion photons correspond to the mass of dark photons. Conversion photon frequencies of 10-300 GHz, for example, correspond to dark photon masses of 0.05-1 meV.

"We are ecstatic that our small team was able to obtain significant results from our high-sensitivity experiments for detecting DPDMs in an unexplored mass range," Adachi concludes.

Read original article...