As the Large Hadron Collider becomes more powerful, physicists search for dark photons

Scientists working on CERN’s Compact Meson Solenoid (CMS) experiment discovered publish They looked for new data on long-lived exotic particles called dark photons.

Dark photons (also known as hidden photons) differ from regular photons (particles of light) in that they are thought to have mass, making them prime candidates to explain dark matter.Dark matter is a catch-all term used to describe seemingly invisible matter in space that can only be seen through gravity effectbut it has never been directly detected and no one is sure what it is.

Physicists at CMS are working to change that. Like particles produced in other CERN experiments, the hypothetical dark photon would be produced by the decay of another particle: the Higgs boson, which was proposed in the 1960s. famous observation 2012. The Higgs boson is thought to decay into a dark photon, which then decays into a displaced muon. The CMS Collaborative is working to limit the parameters within which this process occurs.

CERN’s Large Hadron Collider begins its third run in July 2022, with a greater particle collision capacity than previous runs. This means that the CMS experimental algorithm (or “trigger”) that detects interesting collisions has more events to sift through, and therefore more opportunities to find displaced muons produced by dark photons.

“We have really improved our ability to trigger displaced muons,” says Juliette Alimena of the CMS experiment. statement. “This allows us to collect more muon events than before, ranging from a few hundred microns to a few meters from the collision point. Because of these improvements, CMS is now more likely to find dark photons if they are present they.”

By particle standards, dark photons are considered long-lived: they exist for a billionth of a second. Despite their long lifespan, they’re hard to detect – which is why no one has done it yet. In fact, the search for dark photons has been going on for many years. “Dark photon hunting is both simple and challenging,” physicist James Beacham As told to Gizmodo in 2018. “Simple because the concept is general and simple enough, it is very easy to design experimental searches, but challenging because we really don’t know Where In parameter space, dark photons can exist. “

some scientists are Using small mirrors to find dark matterwhile others are working on Tune into its frequency with a “dark matter radio.” At CMS, physicists are trying to detect particles as they decay into pairs of muons.

To boost CMS, the Large Hadron Collider will soon be upgraded. The upcoming High-Luminosity Large Hadron Collider It will make the facility 10 times brighter and increase the number of Higgs bosons physicists have to study by an order of magnitude. The HL-LHC is expected to be ready for operation in 2029. Meanwhile, the LHC’s Run 3 will last until 2026.

Collider data Continuously creating new subatomic particles questions, but some—those thought to be responsible for the cosmic dark matter—remain elusive. At least until now.

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