A proton collision in the Large Hadron Collider (LHC) has given particle physicists an invaluable insight into the zeptoverse.
The zeptoverse is a scale of nature that is 100 billion times smaller than an atom.
At 10-15 metres, the zeptometre is the smallest scale of the physical world to have ever been explored and could redefine the workings of physics and the Universe as we know them. 100,000 million zeptometres is equivalent to the diameter of a helium atom.
The discovery resulted from scientists at CERN firing protons together in the LHC at almost the speed of light (0.3 million kilometres per second) and spotting one of the most improbable types of particle decay.
The collisions generated numerous particles, such as neutral B mesons, which are smaller than atoms and frequently obtained from particle collisions. Conversely, scientists observed that one of the decaying particles had produced a muon and an antimuon: muons are similar to electrons, but approximately 200 times heavier.
This type of decay is so rare that it has occurred for the first time in four decades. Even theory affirms that muons and antimuons are produced once per ten billion decays of neutral B mesons.
The observation of these particles and their decay helps physicists verify and challenge the postulates of current physics, as well as find clues hinting at the existence and nature of unknown particles.
The results of this experiment are ground breaking, as it marks the first documented occurrence of muon and antimuon generation.
“Physicists have been chasing this decay for more than 40 years. Extreme precision is required to pick the muons out of the overwhelming background.”
Marco Santimaria, Co-Leader of the International Analysis Team, in a press release from CERN
Another reason why it has taken so many decades to observe signals indicating this decay, besides its infrequency, is advances that were made to the LHC in 2024. These resulted in quicker data collection and machine-learning features: the latter of which drowned out background noise potentially obscuring signals emitted from rare decays such as the muon and antimuon one.
This decay directs curiosity towards the constraints of what scientists are able to observe. Currently, results align with contemporary physics theory, but future experiments could shed light on events exclusive to the zeptoverse.
The zeptoverse is only the edge of the abyss of verified and documented knowledge regarding smaller scales, such as the Planck scale. The Planck is the smallest unit theoretically possible in physics: it is 60 trillion times smaller than a zeptometer (1.616255 × 10-35 metres, to be precise).
Physicists do not know if anything exists at that level, as our understanding physics is collectively considered to break down at that level.
If scientists explore the zeptoverse further, it could have many implications in comprehending the first few fractions of milliseconds after the Big Bang, before the universe grew unquantifiable in size. However, particle physicists are still yet to discover what transpires in the zeptoverse.
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