12 March 2019

CERN approves new experiment to look for long-lived, exotic particles

A team of theoretical physicists is launching a new experiment at the CERN research facility in Switzerland to search for particles that could help explain dark matter.

Diagram of FASER

Dr Sebastian Trojanowski, from the Astro-Particle Theory and Cosmology Group in theSchool of Mathematics and Statistics, was one of four researchers who proposed FASER, or the Forward Search Experiment.

The experiment will use CERN's Large Hadron Collider to look for light and weakly interacting particles. Some of these sought-after particles are associated with dark matter, which is a hypothesised kind of matter that does not interact with the electromagnetic force and consequently cannot be directly detected using emitted light.

Astrophysical evidence shows that dark matter makes up about 27% of the universe, but it has never been observed and studied in a laboratory.

The Large Hadron Collider at CERN was used in the discovery of the Higgs Boson in 2012, but has been offline since 2018 for essential maintenance work.

The growing scientific interest in undiscovered particles, particularly long-lived particles and dark matter, means new experiments like FASER have been proposed to expand the scientific potential of CERN’s accelerator complex and infrastructure as part of the Physics Beyond Collider (PBC) study group.

Mike Lamont, co-coordinator of the PBC study group, said: "This novel experiment helps diversify the physics programme of colliders such as the LHC, and allows us to address unanswered questions in particle physics from a different perspective."

FASER will search for a suite of hypothesised particles including so-called "dark photons", particles which are associated with dark matter, neutralinos and others. The experiment will be installed during the LHC's current shutdown and start collecting data between 2021 and 2023.

Jamie Boyd, a co-spokesperson of the FASER experiment, said: "It is very exciting to have FASER approved for installation at CERN. It is amazing how the collaboration has come together so quickly and we are looking forward to recording our first data when the LHC starts up again in 2021."

Eckhard Elsen, CERN’s Director for Research and Computing, said: "FASER is a neat physics proposal that addresses a particular aspect in the search for physics beyond the Standard Model and I am pleased to see it being implemented so efficiently."

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