Cambridge scientists move step closer to holy grail of particle physics with discovery that questions laws of nature
A discovery that brings into question our understanding of the laws of nature left scientists “shaking” with excitement.
Our best current theory of particle physics, which describes all the known fundamental particles that make up our universe and the forces they interact with, may need to be revised after the findings from experiments at CERN’s Large Hadron Collider (LHC).
University of Cambridge scientists and their colleagues at Bristol and Imperial College London say the data hints at the existence of new particles not explained by the ‘Standard Model’.
Dr Mitesh Patel, of Imperial College London, said: “We were actually shaking when we first looked at the results, we were that excited. Our hearts did beat a bit faster.
“It’s too early to say if this genuinely is a deviation from the Standard Model but the potential implications are such that these results are the most exciting thing I’ve done in 20 years in the field. It has been a long journey to get here.”
The LHC is the world’s largest and most powerful particle collider. It accelerates subatomic particles close to the speed of light, before smashing them into one other.
The collisions produce a burst of new particles, which are studied to probe the basic building blocks of nature.
The LHCb experiment - which involves one of four huge particle detectors - studies ‘beauty quarks’, an exotic type of fundamental particle that is not usually found in nature but produced in huge numbers at the LHC.
Once produced in the collision, they should decay equally into electrons and their heavier cousins, muons, according to the Standard Model, but there is evidence to suggest that is not the case.
Dr Paula Alvarez Cartelle from Cambridge’s Cavendish Laboratory, was one of the leaders of the team that found the result, said: “This new result offers tantalising hints of the presence of a new fundamental particle or force that interacts differently with these different types of particles.
“The more data we have, the stronger this result has become. This measurement is the most significant in a series of LHCb results from the past decade that all seem to line up – and could all point towards a common explanation.
“The results have not changed, but their uncertainties have shrunk, increasing our ability to see possible differences with the Standard Model.”
The gold standard for discovery in particle physics is five standard deviations, which would mean there is a one in 3.5 million chance of the result being a fluke. Last week’s result represents three deviations, meaning there remains a one in 1,000 chance that the measurement is a statistical coincidence.
However, a breadcrumb trail of clues leading up to this, involving other, less significant results over seven years that also challenge the Standard Model, means there is quiet optimism.
One of the team, Dr Konstantinos Petridis, of the University of Bristol, said: “The discovery of a new force in nature is the holy grail of particle physics. Our current understanding of the constituents of the Universe falls remarkably short – we do not know what 95 per cent of the universe is made of or why there is such a large imbalance between matter and anti-matter.
“The discovery of a new fundamental force or particle, as hinted at by the evidence of differences in these measurements could provide the breakthrough required to start to answer these fundamental questions.”
Dr Harry Cliff, LHCb outreach co-convener, from Cambridge’s Cavendish Laboratory, added: “This result is sure to set physicists’ hearts beating a little faster. We’re in for a terrifically exciting few years as we try to figure out whether we’ve finally caught a glimpse of something altogether new.”
The LHCb collaboration now aims to verify the results by collating and analysing more data.
Sign up for our weekly newsletter and stay up to date with Cambridge science