New finding of particle physics may help to explain the absence of antimatter

With the help of computer simulations, particle physics researchers may be able to explain why there is more matter than antimatter in the Universe. The simulations offer a new way of examining conditions after the Big Bang, and could provide answers to some fundamental questions in particle physics.

In the Standard Model of particle physics, there is almost no difference between matter and antimatter. But there is an abundance of evidence that our observable universe is made up only of matter – if there was any antimatter, it would annihilate with nearby matter to produce very high intensity gamma radiation, which has not been observed. Therefore, figuring out how we ended up with an abundance of only matter is one of the biggest open questions in particle physics.


Note that the result of this paper, as I understand, is that they found a better way to work out the consequences of the 2-Higgs-Doublet model (2HDM), a hypothetical extension to the Standard Model of particle physics. They found that with certain parameters, it can explain baryogenesis.

I would like to note that models like these also often predict relatively large values for EDMs (electric dipole moments) of fundamental particles like electrons and neutrons. Experiments like ACME where we found that the electron has an EDM of zero (see The Electron is Still Round) tightly constrain these models, such that they have to fine-tune the CP-violating phase that gives rise to a non-zero electron EDM. It seems that even with these constraints, the model can still reproduce an electroweak phase transition (EWPT) which is necessary for baryogenesis and thus explaining matter/antimatter asymmetry.

That being said, the fine-tuning of the electron EDM parameter in itself is a point against models like these (as fine-tuning in theories is generally considered bad). So while the paper shows that the theory can still be tweaked to explain what it wants to explain (baryogenesis), the plausibility of the entire theory itself is increasingly constrained.