- Pallab Ghosh
- BBC News science reporter
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4 hours ago
Credit, Cern
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Physicists working on the largest particle accelerator in the world, the Large Hadron Collider, have discovered a possible flaw in a theory that explains how the building blocks of the Universe behave – the name given to microparticles even smaller than atoms.
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The theory, known as the Standard Model, is the best answer that humanity has to date to explain the functioning of the world around us on a precise scale.
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But we have known for some time that the Standard Model is just the starting point for a more complete understanding of the cosmos.
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The novelty is that evidence of an unexpected behavior of a subatomic particle called the quark bottom can expose cracks in the foundations of this theory that has existed for decades.
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The findings came from data collected by researchers working on the Large Hadron Collider. The collider is a giant machine built in a 27 km circular tunnel under the French-Swiss border.
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It smashes beams of proton particles to search the limits of physics as we know it.
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The mysterious behavior of the bottom quark may be the result of an undiscovered subatomic particle. It would be exerting unexpected force by scientists.
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But physicists emphasize that more analysis and data are needed to confirm any results. Mitesh Patel, from Imperial College London, showed the importance of discussion for the scientific community in an interview with BBC News.
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“We were shaking when we saw the results for the first time, we were very excited. Our hearts were beating faster,” he said.
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“It is too early to say whether this is really a departure from the Standard Model, but the potential implications are such that these results are the most exciting thing I have had in 20 years in the field. It has been a long journey to get here.”
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Credit, Cern
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The particle accelerator was built in a 27 km circular tunnel under the French-Swiss border
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According to science, the particles known as the building blocks of our world are even smaller than the atom.
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Some of these subatomic particles, in turn, are made up of even smaller constituents, while others cannot be broken down into smaller parts. The latter are known as fundamental particles.
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The Standard Model describes all the known fundamental particles that make up the Universe, as well as the forces with which they interact.
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But he cannot explain some of the greatest mysteries in modern physics, such as the so-called “dark matter” or the nature of gravity. Thus, physicists already know that the Standard Model will need to be replaced at some point by more advanced ideas.
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The Large Hadron Collider was built to understand physics beyond the Standard Model.
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Such subatomic particles called “bottom quarks” are produced by the accelerator and are not normally found in nature. They go through a process known as decay, in which one particle is transformed into several smaller ones.
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According to the Standard Model, the bottom quarks must decay in equal numbers of particles of electrons and muons (an elementary particle similar to the electron).
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Instead, however, the process produces more electrons than muons.
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One possible explanation is that an undiscovered particle, known as a leptoquark, is involved in the decay process and makes electron production easier.
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Paula Alvarez Cartelle, from the University of Cambridge, was one of the scientific leaders behind the discovery.
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She commented, “This new result offers tantalizing hints of the presence of a new particle or fundamental force that interacts differently with these particles.”
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“The more data we have, the stronger this result becomes. This measurement is the most significant in a series of results discovered with the accelerator over the past decade and which seem to be aligned. Together, they can point to a common explanation.”
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The scientist, however, is cautious.
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“The results have not changed, but their uncertainties have diminished, increasing our ability to see possible differences with the Standard Model.”
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In particle physics, the gold standard for a discovery is a level called five sigma, in which there is a chance in 3.5 million that the result is mere chance. The measurement of the accelerator is three sigma – meaning that there is approximately one chance in a thousand that the measurement is a statistical coincidence.
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Thus, people should not be too hasty with these findings, according to team leader Prof Chris Parkes of the University of Manchester.
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“We may be on the way to a new era of physics, but if we are, we are still relatively at the beginning of that road at this point. We have seen results of this importance come and go, so we must be cautious,” he said.
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But if confirmed by further analysis and data when the Great Collider is restarted next year, this could be one of the biggest recent discoveries in physics, according to Konstantinos Petridis of the University of Bristol.
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“The discovery of a new force in nature is the holy grail of particle physics. Our current understanding of the constituents of the Universe is remarkably insufficient – we don’t know what 95% of the Universe is made of or why there is an imbalance between matter and antimatter. “
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The results were presented for publication in Nature Physics.
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