Physicists have a massive problem as Higgs boson refuses to misbehave

 Physicists have spotted the Higgs boson performing a brand new trick, but one that brings us no closer to understanding the workings of fundamental particles.

The Higgs boson, discovered at the CERN high energy physics laboratory near Geneva, Switzerland, in 2012, is that the particle that offers all other fundamental particles mass, in keeping with the quality model of high-energy physics. However, despite the work of thousands of researchers around the world, nobody has been ready to determine exactly how it does that or why some particles are more massive than others.

The only thanks to trying and solve that problem is by observing how the Higgs interacts with other particles using the massive Hadron Collider (LHC). For the primary time, both of the most important groups that use it – the CMS and ATLAS collaborations – have observed the Higgs decaying into two muons, a kind of particle we've never directly seen it interact with before. Members of the collaborations presented this work at the virtual International Conference on High Energy Physics.

Some researchers have suggested that particles have different masses because there's over one style of Higgs boson, with each sort of Higgs coupled to a special mass range of other particles.

Muons are much less massive than the opposite styles of particles we’ve seen the regular Higgs interact with, therefore the new discovery makes it more likely there's only 1 Higgs. That behavior is precisely what we expect from the quality model. Adam Gibson-Even at Valparaiso University in Indiana, who hasn’t committed to this work, says that it's an instance of “Higgs boson, exactly as ordered”.

But that leaves the mystery of why particles have different masses completely unanswered. While this result might not be surprising, Gibson-Even says, it's somewhat frustrating because we all know the quality model is incomplete – additionally, to not explaining why particles have different masses, it also doesn’t account for the substance or dark energy. Nevertheless, experimental results are entirely in line with the model.

“It’s a controversy within the sense that we all know that the Higgs boson as-is doesn’t explain this stuff,” says CMS researcher Freya Blekman at the Free University of Brussels, Belgium. If the identical Higgs interacts with both muons and heavier particles, that's another avenue to solving the question of mass closed.

The next step, Blekman says, is to require even more precise measurements of the Higgs interacting with a variety of various particles. Many of those measurements have to be more precise than those the LHC can provide, which is an element of the argument for building a more powerful “Higgs factory” collider, she says.

“We have removed scenarios, but we don’t have a proof yet,” says Beekman. “But this can be what high energy physics is about – we've got tens of thousands of predictions and that we should eliminate them.”