Manchester / New York / Geneva
What happened in the first moments of the origin of the universe? The truth is, we don’t really know, because understanding the origins of the universe in such a short time in the lab takes a lot of energy and precision. But scientists at the European Organization for Nuclear Research (CERN) Large Hadron Collider (LHC) in Switzerland are trying to unravel the mystery.
Our LHCb experiment measured one of the smallest mass differences between two particles, which will help us learn more about the mysterious origins of our universe. The Standard Model of particle physics describes the fundamental particles that make up the universe and the forces acting between them. These elementary particles include “quarks”. There are six types of quarks: high, low, strange, charm, high, and low. Likewise, there are six “leptons” which include the electron, muon, and tau. All quarks and leptons also have antimatter partners.
“The universe was formed 13.8 billion years ago”
The standard model has been verified experimentally to have incredible accuracy, but has significant drawbacks. According to the Big Bang theory, the universe formed 13.8 billion years ago. This theory states that matter and antimatter should be produced in equal amounts from this event. Yet today the universe is almost entirely made up of matter, and that’s a good thing, because antimatter and matter collide in an instant to annihilate each other. One of the biggest questions in physics is why is there more matter than antimatter? Were there processes going on early in the origin of the universe that were more favorable to matter than to antimatter?
To find the answer, we studied a process where matter turns into antimatter and antimatter turns into matter. Quarks combine to form particles called baryons, which include the protons and neutrons that make up the atomic nucleus. Apart from that, quarks and antiquarks combine to form mesons. Mesons without an electric charge undergo a phenomenon called mixing, whereby they spontaneously transform into their own particles of antimatter. In this process, the quark turns into an anti-quark and the anti-quark turns into a quark. These can do it thanks to quantum mechanics.
Precise measurements to trace the origin of the universe
This mechanics governs the universe on the smallest scale. According to this theory, particles can be in many different shapes at the same time, essentially a mixture of many different particles. This feature is called layering. Accurate measurements are essential to trace the origin of the universe. To find out why the universe produced less antimatter than matter, we need to know more about the asymmetry in the production of both. Some unstable particles destroy themselves differently from their respective antimatter particles.
This must have been the reason why there is an excessive amount of matter in the universe. After an extended shutdown, the LHC will be operational next year and the new and improved LHCB detector will collect more data, further increasing the sensitivity of the measurements. In the meantime, theoretical physicists are working on new calculations to explain this result. We may not yet fully solve the mysteries of the universe, but the new advanced LHCb detector will open the door to precise measurements, which have the potential to detect unknown phenomena.
(Authors – Martha Hilton from Manchester University, Nathan Jurik from Syracuse University and Sasha Stahl from CERN)