 "A new study has shed light on one of humankind's fundamental queries: Why does the universe exist? Image courtesy: Nasa")
A new study at CERN has provided critical insights into one of the most fundamental questions in physics: why does anything exist at all? Researchers working on the Large Hadron Collider beauty (LHCb) experiment have observed a rare form of symmetry violation in the decays of beauty baryons– particles containing a bottom quark.
The finding offers vital clues to the long-standing mystery of why the universe is composed predominantly of matter, rather than being annihilated by an equal amount of antimatter.
The study, published in Nature, reports the observation of charge–parity (CP) violation in a baryonic decay process, marking a significant development in the quest to understand the imbalance between matter and antimatter in the early universe.
What did the scientists observe?
The experiment focused on a specific decay of the beauty baryon, into a proton, a kaon (K−), and two pions (π+ and π−). This decay can occur via two different quark-level pathways: one involving a bottom-to-up (b → u) transition and another involving a bottom-to-strange (b → s) transition.
Crucially, the researchers found that these two processes do not behave symmetrically when matter is swapped for antimatter. This violation of CP symmetry is a direct indication that the laws of physics are not entirely the same for matter and antimatter– a foundational requirement for explaining why the universe didn’t simply self-destruct in a flash of mutual annihilation shortly after the Big Bang.
Why is CP violation so important?
CP violation had previously been observed in the decays of mesons– particles made of a quark and an antiquark. However, baryons (made of three quarks) are less explored in this context. The new findings from the LHCb collaboration represent the first clear evidence of CP violation in baryon decays, expanding the frontier of known symmetry-breaking phenomena.
This asymmetry is a necessary component in explaining the observed dominance of matter in the universe. Without it, the Standard Model predicts that equal amounts of matter and antimatter would have been produced in the early universe– leading to their mutual destruction.