Welcome to the CMS Experiment at CERN
The world’s most sophisticated experiment
The CMS experiment at CERN brings together scientists and engineers from around the world to tackle the toughest questions about the fundamental laws of nature. The CMS detector and collaboration study particle collisions from the Large Hadron Collider to investigate why the Universe is the way it is, what it is really made of, and how it will evolve.


Small particles, big questions
The CMS Experiment studies particles produced in the Large Hadron Collider at CERN to understand the principles that govern the cosmos and answer to fundamental questions: Why are some particles more massive than others? Where did all the antimatter go?
And what is the nature of dark matter? With over 1,500 papers published to date, researchers at CMS are some of the best in the world.


At the edge of the unknown
CMS pushes computing and AI technology
to its limits to investigate the mechanisms
of the universe.

A camera for the invisible
The CMS detector is located 100 metres underground and takes precision measurements of subatomic particles.

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HiLumi CMS
The High-Luminosity LHC, set to begin operation
in 2030, will deliver roughly five times more collisions than all previous runs combined.
To keep up with the collision rate, the new
HiLumi CMS detector will be dramatically faster, more robust and more precise than ever before.


Live from the detector


See it for yourself
Go 100 metres underground at our experimental site in Cessy, France, or during one of our live virtual visits.