We shouldn't be here.
Humans should never have existed.
According to the Big Bang theory, the creation of the universe resulted in equal amounts of matter and antimatter. Actually, the idea goes beyond the Big Bang theory. The fact that matter and antimatter are created in equal amounts is part of our Standard Model of particle physics. It's how the Universe works. A particle with a certain charge is always balanced by an antiparticle with the opposite charge. If an electron is created, a positron (the antimatter version) is also created. It's not just a "model". Scientists have confirmed it many times in real world experiments. It always comes out the same. Where there is matter, there is antimatter.
The problem is, when matter meets antimatter, they cancel each other out. Or, more accurately, they annihilate each other. There is a massive explosion of light. Nothing survives. The Big Bang that launched our Universe should have resulted in nothing. No stars or planets, no human beings. All the matter should have been annihilated by all the antimatter. The Universe should just be a featureless soup of radiation.
Except -- obviously -- it isn't. Somehow enough matter survived to make you and the Earth and everything in the Universe. The question is, why did any matter survive the Big Bang? It's the biggest mystery in modern cosmology.
In a study published this March in the journal Nature, a team of scientists from no less than 109 research institutions attempted to solve it.
The study was done using the Large Hadron Collider (LHC), maybe the most impressive scientific instrument ever built. If you're going to answer the biggest question in the Universe, it makes sense to use the big guns. The LHC is 17 miles long -- the largest particle accelerator in the world. And it's buried over 300 feet underground. The crazy facts don't stop there. The LHC uses 1,232 magnets cooled to -456 degrees Fahrenheit, which is colder than deep space, so cold atomic motion essentially stops. Protons in the LHC travel nearly at the speed of light. The collisions between particles can generate over 13 tera-electronvolts of energy. We don't know how much that is, but they say it's close to the power that created the Universe, so that's a lot of energy.
Using the LHC, scientists can produce matter and anti-matter collisions. They can, in some small way, reproduce the Big Bang.
To answer the question of our existence, the research team gathered data for eight years from high-energy proton to proton collisions, and the antimatter that results. Specifically, they focused on one particle and its antimatter counterpart: the Lambda b baryon. It's actually a combination of three quarks, the exact particles created in the Big Bang.
Researchers focused on Lambda b baryon's decay, or how it transforms from quarks into more stable particles. And it's in this transformation that they uncovered the mystery. For the first time in history, scientists observed what's called a charge-parity (CP) violation in the decay of matter and anti matter. Hard to get excited about this if it sounds like gibberish, but it's actually a big deal.
Imagine the Big Bang creates quarks that turn into protons that become the building blocks of life. At every stage in these transformations, the particles have antimatter counterparts that cancel them out. But this study found that, as Lambda b baryon decays, it does so at a slightly different rate than its antimatter pair. One in a billion times, the matter wasn't matching with the antimatter. The pairing was broken.
Something caused matter and antimatter to decay in different ways, just enough to allow a little matter to survive. And the antimatter that doesn't find a matter partner decays into energy, effectively disappearing over time. In scientific terms, they found, "the measured global CP asymmetry is (2.45 ± 0.46 ± 0.10)%, with a significance of 5.2 standard deviations". What does that mean? Well, imagine you have 100 marbles and you expect 50 to be red and 50 to be blue. Each red has a blue match. The study showed there are 2 or 3 more red marbles. A small difference, but if you're talking about matter vs antimatter, it's enough to launch a Universe.
We were 2 blue marbles away from never existing.
Scientists think this study hints at a "new physics". The Standard Model doesn't account for matter escaping its antimatter match. The CP violation observed in this study explains how it can happen. At a subatomic level, where quarks are turning into photons, something in the process is putting its finger on the scale, favoring matter just a little bit over antimatter.
But a mystery remains. What pushed the Universe in our direction? Whose finger was it?