Finding the Higgs boson, a breakthrough in fundamental science that in 2012-2013 revealed an elementary reality about how the universe works, has highlighted how much more physics needs to be done.
Discovering the Higgs boson plugs a large hole in the standard model, the highly tested theory that shows all matter is made of a number of elementary particles that interact through four fundamental forces—strong, weak, electromagnetic and gravitational forces. Together, these comprise everything we currently understand about matter.
“The standard model provides a consistent explanation of the subatomic world,” said Jonathan Bagger, a high-energy physicist who is the incoming director of Canada’s national laboratory for particle and nuclear physics. “The Higgs boson is at the center of the model. It’s the linchpin. But there’s plenty of the universe that the standard model doesn’t address.”
In fact, all of the stuff that the standard model explains represents only 4.9 percent of the universe. Dark matter, which physicists and astronomers can’t actually detect with their instruments, makes up 26.8 percent of the universe, and a whopping 68.3 percent is composed of dark energy, a hypothesized form of energy that is also currently undetectable.
“Is particle physics done now that we have the Higgs boson?” he says. “Neutrinos are massless in the standard model, but in the real world they are not. The evidence for the existence of dark matter is overwhelming, but there is no dark matter in the standard model. There are still major questions about cosmic acceleration. Particle physics is not done.”
The Higgs particle itself is outside the model. When its mass is plugged in, Bagger says, the picture goes wonky and the math says that quantum fluctuations over time should destroy the universe. “There are several options to fix the math, but none of them are within the standard model,” he says.
Timothy Meyer, the incoming chief operating officer of the Fermi national particle physics lab in the U.S., says the key is for global participation to answer the massive amount of questions.
“Broadly speaking, U.S. dominance of science has faded,” Meyer said. “For the first time, the U.S. has taken a global view in research efforts.”
A document meant to guide the U.S. through this next generation of particle physics called the P5 report lays out priorities. Among them are pursuing understanding of the neutrino at Fermi; supporting efforts by the European effort at CERN, where existence of the Higgs boson was confirmed; being involved in a new big accelerator project in Japan; trying to detect dark matter; and augmenting research into the cosmic microwave background, the detectable radiation everywhere that is a remnant of the earliest moments of the universe.
“This plan represents a significant change for the U.S.,” Meyer said. “This is a challenging time for particle physics.”
Tatsuya Nakada, a particle physicist with CERN and the Swiss Federal Institutes of Technology, said particle physics need these grand strategies because the facilities needed for the experiments are big and often the technology to run the tests needs to be created. These innovations, he said, can then find their way to commercialization and industry.
The group’s comments on the future of particle physics after the Higgs boson discovery came During a Monday morning discussion at the 2014 Euroscience Open Forum. The panel of physicists continued on a conversation started during the event’s opening ceremony that began to tease out the breadth of science’s ignorance throughout the discipline of theoretical physics.
“We’re so proud of ourselves as particle physicists that we now understand five percent of the universe, but there’s lots left to discover,” Bagger said.
Top Image: Computer simulation of particle traces from an LHC collision in which a Higgs Boson is produced. Courtesy of CERN/Lucas Taylor