One of the big questions in science is not just “why are we here?’ It’s, “why is anything here?” Scientists at CERN have been looking into this one over the last several years, and there’s still no good answer. In fact, the latest experiment from physicists working at the Swiss facility supports the idea that the universe doesn’t exist. It certainly seems to exist, though. So, what are we missing?The latest experiments found no such asymmetry.
In particle physics, the Standard Model describes the four known fundamental forces in the universe: the gravitational, electromagnetic, weak, and strong. The first two have very clear consequences in the universe while the other two are detectable only at the subatomic scale. The Standard Model has been supported by experimentation, but it predicts that the big bang that created the universe would have resulted in equal amounts of matter (us and everything around us) and antimatter (rare). If they were equal, why didn’t the early universe cancel itself out, leaving just a sea of energy?
Scientists have been searching for some feature of matter or antimatter that would have made the early universe asymmetrical.
I don't see why this is a problem. If the big bang started with high entropy, and if matter and anti-matter were equally produced and symmetrical, then we could expect them to cancel out. But we know that the big bang started with very low entropy, because the universe's entropy has been increasing ever since.
You could say, Why is there any hydrogen? A hot big bang in thermal equilibrium would have fused all the hydrogen into helium in the first few minutes, and there would be none left for making stars and we would not be here.
I don't know the answer to that, except to say that the big bang must have been low entropy, not high entropy, and therefore those nuclear reactions did not take place.
High energy and high entropy and standard model would predict equal amounts of matter and anti-matter, but that did not happen. Maybe the big bang was a matter-only big bang, with no anti-matter. Some anti-matter got produced incidentally, but the vast excess of matter is no more surprising than the very low entropy.
Update: Peter Woit summarizes:
The paper reports a nice experimental result, a measurement of the antiproton magnetic moment showing no measurable difference with the proton magnetic moment. This is a test of CPT invariance, which everyone expects to be a fundamental property of any quantum field theory. The hype in the press release confuses CPT invariance with CP invariance. We know that physics is not CP invariant, with an open problem that of whether the currently known sources of CP non-invariance are large enough to produce in cosmological models the observed excess of baryons over antibaryons. An accurate version of the press release would be: “experiment finds expected CPT invariance, says nothing about the CP problem.”In other words, 1970 physics was confirmed again, and nothing new found.