By Emily Barrett, Third year, Physics
After three years of maintenance and upgrades, the Large Hadron Collider (LHC) at CERN has been switched back on and will allow researchers at the University of Bristol to tackle fundamental questions about the universe.
With its 27-kilometre ring and superconducting electromagnets, the LHC on the French-Swiss border is the world’s largest and most powerful particle accelerator. Within it, protons or ions – particles from a group called ‘hadrons’ – are accelerated to close to the speed of light and made to collide at different points around the machine. These collisions are then investigated by particle physicists such as those at Bristol, who study the smallest detectable particles that make up matter.
One of the most famous ‘new physics’ discoveries from the LHC was the detection of the Higgs boson in 2012
On 22 April 2022, two beams of protons once again circulated in the LHC after its three-year maintenance period. According to the head of CERN’s Beams department, these first beams ‘represent the successful restart of the accelerator’, although the ‘high-energy, high intensity collisions are a couple months away’.
This is the third run of the LHC, which promises record-breaking energy levels. It will allow researchers to approach questions left open by the Standard Model of particle physics – a theory which describes the fundamental particles and their interactions. The University of Bristol’s particle physics department, in particular, has been awarded £2.38m by the Science and Technology Facilities Council (STFC) to fund their research over the next three years.
The particle physics group at Bristol carries out research projects at CERN and has analysed previous LHC data which has ‘thrown up some intriguing discrepancies’, according to Prof. Joel Goldstein from Bristol University’s School of Physics. With the new data from the LHC, the group will be able to make more precise measurements and establish the origins of these discrepancies – whether they are the signs of new physics or simply statistical fluctuations.
One of the most famous ‘new physics’ discoveries from the LHC was the detection of the Higgs boson in 2012, although this particle was in fact predicted in the 1960s. This theory, which earned François Englert and Peter Higgs the 2013 Nobel Prize in physics, proposed that particles get their mass by interacting with an invisible ‘Higgs field’. Today, the Bristol particle physics group is continuing to investigate the Higgs boson by developing techniques to see if it has exotic properties.
It remains to be seen what this third run of the LHC will contribute to our understanding of physics. As Prof. Mark Thomson, the Executive Chair of STFC, says ‘the global science community will now eagerly await the results’.
Featured Image: Unsplash/Erwan Martin
What do you predict will be learned from the return of the LHC?