Ten years ago today, on July 4, 2012, the ATLAS and CMS collaborations using the Large Hadron Collider at CERN announced the discovery of the Higgs Boson particle. It was the long-sought crucial component of our theory of particle physics, the Standard Model. It underpins how particles in the universe have mass.
What is the Higgs Boson?
Throughout the universe, there is a field known as the Higgs field. Any particle with mass interacts with this field and that interaction is mediated by the Higgs Boson. The Boson itself interacts with the field so it has a mass about 125 times heavier than the proton, the positively charged particle that sits at the center of atoms.
A famous analogy explaining how particles interact with the field has a celebrity and an average person entering and walking through a cocktail party. The celebrity [a heavy particle] will attract more party guests [the Higgs bosons] than the average person [a lighter particle].
This is how the mass of fundamental particles comes to be – quarks, electrons, etc – and coming together in atoms, they make up us and everything you see.
Who discovered the Higgs Boson?
This theoretical framework was put forward by three independent groups: Peter Higgs, Robert Brout and François Englert, and Gerald Guralnik, C. R. Hagen, and Tom Kibble back in 1964. But it was only with the power of the Large Hadron Collider (LHC) at CERN, that the Higgs boson could be hunted. There, the detectors ATLAS and CMS recorded the collisions of proton beams ready to spot any new particles that might emerge.
Data collection began in March 2010, and by July 2012 they had enough evidence to support the discovery. They had reached the golden standard of 5 sigmas, which means that there was about one chance in 3.5 million that the result was a fluke. The discovery was a window to a completely new area of particle physics.
“The Higgs sector is directly connected with very profound questions related to the evolution of the early Universe and the stability of the vacuum, as well as to the striking mass pattern of matter particles,” ATLAS spokesperson Andreas Hoecker said in a statement.
“Each particle’s relationship with the Higgs boson is special, and provides a unique test of the Standard Model. Over the past ten years, we have observed and measured all of the main production and decay mechanisms of the Higgs boson as summarised in today’s paper.”
In 2013, Higgs and Englert won the Nobel Prize for Physics for the discovery.
Why is it called the "God Particle"?
The nickname the "God Particle" may not be very popular among physicists but it was a physicist who made it popular. The Nobel Prize-winning physicist Leon M. Lederman together with science writer Dick Teresi wrote a popular science book about the Higgs Boson in 1993 with the title The God Particle: If the Universe Is the Answer, What Is the Question?, an excellent strategy to crystallize the importance of this subatomic item in the public's psyche.
"Why God Particle? Two reasons. One, the publisher wouldn't let us call it the Goddamn Particle, though that might be a more appropriate title, given its villainous nature and the expense it is causing. And two, there is a connection, of sorts, to another book, a much older one," Lederman explained in the book.
The fact that the Higgs field gives mass to particles is crucial to the universe. There would be nothing otherwise. The boson is the cornerstone of not just our model of physics, but of all creation itself.
How did the discovery of Higgs Boson change physics?
Since the initial discovery, the ATLAS experiment has recorded 30 times more Higgs Bosons events. This has allowed researchers to test the behavior of the Higgs Boson with other fundamental particles. Deviations from the Standard Model, even minimal, could tell us about what fascinating physics is yet to be found.
The findings of the first decade of Higgs are mostly from the second run of the Large Hadron Collider, between 2015 and 2018. The observations are remarkably consistent with the prediction of the Standard Model, which allowed physicists to put some interesting and stringent constraints on the many models that try to explain phenomena beyond the Standard Model.
While hints of physics beyond the Standard Model have become more common over the last few years, the most glaring omission of the model remains gravity. So there’s definitely room to expand it. Another active area of research is dark matter, the hypothetical substance that should outweigh regular matter in the universe by five-to-one.
“The Higgs boson itself may point to new phenomena, including some that could be responsible for the dark matter in the universe,” CMS spokesperson Luca Malgeri said. “ATLAS and CMS are performing many searches to probe all forms of unexpected processes involving the Higgs boson.”
“Any new particle with mass might interact with the Higgs boson," explained Guillaume Unal, ATLAS Physics Coordinator. “We could observe these particles directly in dedicated searches or indirectly by precisely measuring the kinematic and symmetry properties of the Higgs boson. New particles occurring in quantum loops might alter these properties from those predicted by the Standard Model.”
What's next for the "God Particle"?
The LHC Run 3 begins tomorrow, running around the clock for close to four years at a record energy of 13.6 trillion electron volts. This will allow an even more precise understanding of the Higgs Boson and maybe even new particles.