The Standard Model of particle physics is the best description we have of how particles and forces interact in the world. But it is by far not perfect, and over the years new discoveries have indicated that there’s much more out there in the universe.
A group of European physicists has now suggested an extension to the Standard Model, and they claim it solves some of its biggest problems, like the nature of dark matter, how neutrinos change from one type to the others, and why the universe is made of matter and not anti-matter.
The scientists have proposed that these and other problems can be solved by the addition of six new particles to the Standard Model. Three are right-handed neutrinos, which are just like regular neutrinos except they spin in the opposite direction. Another is a new fermion, which decays into quarks and disappears in the modern-day universe, and the other two are new particles that create an interactive field.
The team assumes that this new field interacts with the Higgs field (which gives particles mass) and, according to their model, it can generate the exponential expansion the universe experienced in its first instants, which is known as cosmic inflation.
While the proposed field is crucial to explaining what happened just after the Big Bang, one of the field’s particles might play a role in the entire history of the universe: It could be dark matter. At the very beginning, their field generates large quantities of “axions”, very light particles that don’t interact much with the “standard” particles. The properties they have found in their model, which they dubbed SMASH (Standard Model Axion Seesaw Higgs), makes these axions a good match for what cosmologists believe dark matter is made of.
SMASH was announced in a paper, available to read online on arXiv, and although it explains several missing features of the Standard Model, it has not been proven yet. The particles predicted by the researchers could soon be found by several current or upcoming experiments like CULTASK or MADMAX.
“The best thing about the theory is that it can be tested or checked within the next 10 years or so,” co-author Andreas Ringwald, from the German Electron Synchrotron (DESY) in Germany, told New Scientist. “The battle is open.”
With experiments running all over the world, the quest for improving the Standard Model is on. But we don’t know when or even if we’ll get there.