Scientist’s experiment with Large Hadron Collider could shed light on invisible dark matter

With the help of the Large Hadron Collider, Dr. Sebastian Trojanowski and his colleagues hope to observe the mysterious invisible mass thought to be responsible for adding gravity to galaxies and other bodies. Adam Warżawa/PAP

A Polish physicist at the forefront of new research into dark matter, the mysterious substance believed to make up 85 per cent of all matter in the universe, could be on the verge of discovering a fifth force of nature.

With the help of the Large Hadron Collider (LHC) in Switzerland, Dr. Sebastian Trojanowski and his colleagues hope to go where no scientists have gone before and observe the mysterious and, until now hypothetical, invisible mass thought to be responsible for adding gravity to galaxies and other bodies. 

To be sensitive to the many possible forms of light, weakly-interacting particles, and to differentiate signal from background, the FASER detector has several major components.CERN

Dr. Trojanowski, who came up with the idea of how to observe dark matter whilst doing an internship at the University of California, Irvine, has developed a multi-detector concept which is now being constructed in the LHC’s service tunnel.   

Trojanowski said: "Such particles – if they are sufficiently light, if they are produced quite rarely and moreover, they fly along the axis of proton beams - then they could slip experimenters’ eyes.

"It would be hard to see them as, for example, a significant signal of missing energy in energy balance of collision’s products. 

Map showing the proposed location of FASER in the TI12 tunnel. FASER's location is 480 m away from the ATLAS interaction point on the beam collision axis, after the LHC ring starts to curve.CERN

“A chance of their possible detection is placing the detector at a certain distance from the production point and trying to register the predicted decay products. 

“A condition which must be met in order for this scenario to work is that the mass of the sought particles must be larger than the combined mass of the lightest products of the possible decay – for example electron-positron pair.”

Dr. Trojanowski came up with the idea of how to observe dark matter whilst doing an internship at the University of California.ncbj.gov.pl

The experiment known as FASER, short for Forward Search Experiment, was conceived by Trojanowski and theoretical physicists professor Jonathan Feng, Iftah Galon and Felix Kling at the University of California, Irvine. 

Funded by the US-based Heising-Simons and Simons Foundations, FASER will be located 480m from the ATLAS detector in one of the LHC’s service tunnels. 

3D picture of the planned FASER experiment in its tunnel.CERN

The system will include scintillators, magnets, drift chambers and a calorimeter, which measures the energy of products, if the decay really happens. 

“The whole system is a few metres long and partially composed of spare parts from other functioning LHC experiments," added Trojanowski, who is currently a research associate at Sheffield University.

The Large Hadron Collider is the biggest scientific experiment in the world.Adam Warżawa/PAP

Now the four initiators of FASER and twenty other scientist from all over the world who cooperate on the project have until late 2020 to install and test the multi-detector. 

Once the ongoing Long Shutdown 2 is over, the experiment will run and collect data for three years, 2021-2023.