Confused after reading the following article.
https://www.cbc.ca/radio/ideas/particle-astrophysics-studying-origin-of-universe-1.6733153
In: 17
I’m not sure there is an ELI5 answer, but [this article](https://www.quantamagazine.org/neutrino-experiment-intensifies-effort-to-explain-matter-antimatter-asymmetry-20131015/) gives the following explanation:
> A fraction of a second after the Big Bang, those primordial heavy neutrinos would have undergone a process known as leptogenesis: Calculations show they would have decayed asymmetrically, generating slightly fewer leptons (electrons, muons and tau particles) than antileptons. By a conventional Standard Model process, the antilepton excess would then have cascaded into a one-part-per-billion excess of baryons (protons and neutrons) over antibaryons. “The baryons and antibaryons annihilated each other, and then the tiny imbalance left over is the matter we have today,” Caldwell said.
>
> “If the neutrino is its own antiparticle, then the so-called leptogensis mechanism to explain the matter-antimatter asymmetry will be very plausible,” Schwingenheuer said.
Basically, there is a complicated decay chain that could result in an excess of matter, but only if you’re allowed to treat neutrinos and antineutrinos the same. If one stage needs a neutrino as an input, and another stage produces an antineutrino as an output, you can chain them together only if an antineutrino is the same as a neutrino, i.e., if a neutrino is its own antiparticle.
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