A welder works in the Large Hadron Collider's tunnel during its upgrade for more powerful particle collisions.
Awarding the Nobel Prize for physics to the scientists who kicked off a quest to find a theoretical subatomic particle brings the nearly 50-year story full circle — like the circular tunnel of the $10 billion Large Hadron Collider, where the elusive Higgs boson was finally detected. But it's not the end of the story.
"It's important to realize that this doesn't close the book," said Don Lincoln, a physicist at Fermilab who is also a member of the Large Hadron Collider's CMS experimental group. "There are still chapters to read."
So what's the next chapter about? In a word, supersymmetry.
Looking for sparticles
Supersymmetry is a hypothesis suggesting that all the particles we've detected so far, including the Higgs boson, have much more massive, yet-to-be-detected partners that blink into existence for merely an instant. If the Higgs boson explains how mass arises, supersymmetric particles — also known as "sparticles" — would explain a lot of the weirdness surrounding the distribution of matter in the universe.
For example, astronomers have determined that all the stuff that we see in the cosmos accounts for only 10 percent of the universe's matter content, based on gravitational observations. The other 90 percent is classified as "dark matter," and for decades, physicists have been trying to figure out what it's made of. Right now, supersymmetric particles are the prime suspects.
Supersymmetry could explain why the mass of the Higgs boson is about 16 orders of magnitude lighter than theory suggests it should be. One possibility is that there's a supersymmetric, dark matter partner for the Higgs boson — a subatomic behemoth that's been nicknamed the "Higgsino."
"The fact that the Higgs boson is so small points to this little thread in the quilt that we've made, and we're going to tug on it," Lincoln said. "We don't know what the answer is, but we know that the mass of the Higgs being so small is pointing to a mystery."
Greg Landsberg, a Brown University physicist who serves as the physics coordinator for the CMS group, said supersymmetry would provide a "very elegant mathematical solution" to the dark matter mystery.
"So far, we haven't seen anything, but not seeing something doesn't mean it doesn't exist," Landsberg told NBC News.
The Large Hadron Collider is now in the midst of a two-year shutdown, but when it returns to smashing protons at nearly the speed of light in 2015, it's expected to ramp up from its previous top energy of 4 trillion electron volts per beam to its maximum energy of 7 trillion electron volts per beam. That could conceivably shake loose the first signs of supersymmetry.
The collider could also shake loose evidence of extra spatial dimensions, or the fleeting signature of super-microscopic black holes. Could it shake loose another Nobel Prize? It's too early to predict, but Lincoln said "we're hopeful that the future of particle physics is bright over the next five or 10 years."
Widening the path to a Nobel Prize
By then, the Royal Swedish Academy of Sciences just might figure out a way to recognize more than three individuals with a scientific Nobel Prize. The fact that thousands of physicists are working together to make discoveries at the LHC demonstrates how research has become a large-group activity.
"It would be nice if they figured out some way to at least give the prize collectively," said Gerald Guralnik, a Brown University physicist who almost certainly would have shared in the prize if it weren't for the three-name limit. Guralnik and two of his colleagues, Carl Hagen of the University of Rochester and Tom Kibble of Imperial College London, wrote a key paper about the Higgs mechanism that was published just a few weeks after Higgs' own paper in 1964.
"We're human, so it stings a bit," Guralnik told NBC News. "We would have been happier if we were a part of it. But we're so proud to have made contributions. We're still in amazement that experimentalists were able to find [the Higgs boson]. After 50 years, you give up hope."
Kibble and Hagen voiced similar sentiments. In a statement, Kibble said it was "no surprise that the Swedish Academy felt unable to include us, constrained as they are by a self-imposed rule that the prize cannot be shared by more than three people." Hagen said he wasn't surprised, either, but added that he was "nonetheless very proud of the work we did, at how complete our explanation was, and how that has contributed to our understanding of how particles obtain mass."
Amid the flap over the federal government's shutdown, Guralnik said the decades of work that went into discovering the Higgs boson and expanding the frontiers of physics illustrated how necessary it was to have government support for basic science.
"Without the government support, there is no work like this," Guralnik told NBC News. "This kind of work has a 100-year payoff time. ... For this one, maybe it's 150 years."
More resources on the Higgs quest:
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Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding +Alan Boyle to your Google+ circles. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.
First published October 8 2013, 4:46 PM