Scientists from the European research outfit CERN rocked the physics world Wednesday with the announcement that they've discovered a new subatomic particle that appears to be the famed Higgs boson first posited half a century ago.
The Higgs boson is an important find because it answers the fundamental question of where mass comes from and completes the Standard Model of Physics, which describes much of what we know of the universe through the interactions of four fundamental forces and 12 subatomic particles.
But finding the "God particle" is only the beginning, according to College of William & Mary physicist Marc Sher.
While the Higgs boson discovery provides an explanation of where mass comes from, "what it does not explain is how those values of mass are generated," Sher said in a telephone interview.
The Higgs boson is thought to generate an invisible field known as, appropriately, the Higgs field. Subatomic particles like protons and electrons gain mass by interacting with this field, but it's still not clear why certain kinds of particles interact differently, resulting in different masses.
To illustrate interactions between particles and the Higgs field, Sher offers an analogy: Imagine a room full of people at a party. If a relatively unknown person enters the room, they can pass through the crowd with relative ease. But if the Queen of England shows up, she'll immediately be beset by well-wishers and won't be able to cross the room as quickly.
So, in this hypothetical Higgs field party, what makes some particles wallflowers and others the center of attention? That's the burning question, according to Sher.
There also remain many questions outside of the Standard Model of physics that aren't answered by the Higgs boson discovery. One big question mark looming over physics is the nature of dark matter and dark energy - which, despite making up about 23 percent and 72 percent of the total mass-energy of the universe, respectively, are very little understood. Dark matter does not emit or absorb light, and is therefore invisible to telescopes.
CERN also isn't done with examining the Higgs boson. Though researchers on two teams are certain they've found a particle consistent with the Higgs boson, the follow-up question scientists are trying to answer is what kind of Higgs boson they're seeing.
The basic theory of the Higgs boson is the simplest way to account for the masses of subatomic particles. But there are other ways that the Higgs boson could work. Certain formulations of the Higgs mechanism are tied to theories that predict extra dimensions of space; others are linked to supersymmetry, a theory that could account for all of the dark matter pervading our universe, according to CERN.
Our glimpse of the Higgs boson is like spotting a familiar face from far away, the agency said in a release on Wednesday.
"Closer observation might be needed to tell whether it's an old friend who loves coffee, or her identical twin sister who favors tea," CERN said.
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