Scientists at the Large Hadron Collider have uncovered new clues in one of the universe’s greatest mysteries: why we exist at all. Two groundbreaking discoveries about how matter and antimatter behave differently might help explain why our universe is made of matter instead of nothing at all.
The findings from the LHCb collaboration at CERN represent the first evidence of a rare quantum effect in two new types of particle decays – a crucial step toward understanding why matter won out over antimatter in the early universe.
The mystery stems from the birth of the cosmos itself. When the Big Bang created the universe 13.8 billion years ago, it should have produced equal amounts of matter and antimatter. Yet today, the universe is made almost entirely of matter – the stuff that makes up everything we can see and touch.
This imbalance has long puzzled physicists. While their main theory, the Standard Model of particle physics, predicts some difference in how matter and antimatter behave (known as CP violation), this effect isn’t strong enough to explain why matter so thoroughly dominated antimatter in our universe.
Now, analyzing data from proton collisions at the Large Hadron Collider, researchers have found evidence of this matter-antimatter asymmetry in two new places. First, they detected it in the decay of particles called bottom lambda baryons (made of three quarks) into a lambda baryon and two kaons. They also found it in the decay of charged beauty mesons into specific combinations of other particles.
Both discoveries reached what physicists call “3.2 standard deviations” – a level that indicates strong evidence but falls just short of the formal threshold for claiming a definitive discovery.
These findings are significant because until now, this asymmetry had only been definitively seen in certain types of particles called mesons. Finding it in baryons (which make up most ordinary matter) and in new types of meson decays opens up fresh avenues for understanding the matter-antimatter puzzle.
The research team made these discoveries by meticulously counting the number of times particles and their antimatter counterparts decayed in different ways, looking for subtle differences that reveal nature’s preference for matter over antimatter.
The discoveries mark important steps toward understanding whether this quantum effect exists more broadly in nature. Researchers expect that data from the current run of the Large Hadron Collider and its planned high-luminosity upgrade will provide even more insights into this fundamental mystery of our universe’s existence.
If these findings are confirmed with more data, they could help explain one of the most basic facts about our universe – why there was enough matter left over after the Big Bang to form galaxies, planets, and ultimately, us.