Large Hadron Collider detects strange particle behavior that could rewrite physics

Recent findings from research we have been carrying out at the Large Hadron Collider (LHC) at Cern in Geneva suggest that we might be closing in on signs of undiscovered physics. If confirmed, these hints would overturn the theory, called the Standard Model, that has dominated particle physics for 50 years. The findings suggest the way that specific sub-atomic particles behave in the LHC disagrees with the Standard Model.

Fundamental particles are the most basic building blocks of matter – sub-atomic particles that cannot be divided into smaller units. The four fundamental forces – gravity, electromagnetism, the weak force and the strong force – govern how these particles interact. The LHC is a giant particle accelerator built in a 27km-long circular tunnel under the French-Swiss border. Its main purpose is to find cracks in the Standard Model . This theory is our best understanding of fundamental particles and forces, but we know it cannot be the whole story. It does not explain gravity or dark matter – the invisible, so far unmeasured type of matter that makes up approximately 25% of the universe. In the LHC, beams of proton particles traveling in opposite directions are made to collide, in a bid to uncover hints of undiscovered physics. The new results come from LHCb , an experiment at the Large Hadron Collider where these collisions are analyzed. The result comes from studying the decay – a kind of transformation – of sub-atomic particles called B mesons. We investigated how these B mesons decay into other particles, finding that the particular way in which this happens disagrees with the predictions of the Standard Model. The Standard Model is built on two of the 20th century’s most transformative advances in physics; quantum mechanics and Einstein’s special relativity. Physicists can compare measurements made at facilities such as the LHC with predictions based on the Standard Model to rigorously test the theory.

Key points

• Fundamental particles are the most basic building blocks of matter – sub-atomic particles that cannot be divided into smaller units.
• The four fundamental forces – gravity, electromagnetism, the weak force and the strong force – govern how these particles interact.
• The LHC is a giant particle accelerator built in a 27km-long circular tunnel under the French-Swiss border.
• Its main purpose is to find cracks in the Standard Model .
• This theory is our best understanding of fundamental particles and forces, but we know it cannot be the whole story.