The Large Hadron Collider (LHC) at the European Council of Nuclear Research (CERN) is a gigantic particle collider (synchrotron) in Geneva, Switzerland. Ten years ago, on this date (July 4th), LHC announced that physicists across the globe had been eagerly awaiting the discovery of the Higgs Boson particle for decades.
For decades, particle physicists had anticipated proving the existence of the Higgs Boson as the “last missing piece” of the Standard Model of Physics. The particle was crucial in confirming the presence of the Higgs field, which gives mass to all elementary particles.
The Higgs boson was dubbed the ‘God particle’ in Leon M. Lederman and Dick Teresi’s 1993 book The God Particle: If the Universe Is the Answer, What Is the Question? because of the long-held assumption by physicists that the particle had to exist, despite any evidence. The authors wrote: “This boson is so central to the state of physics today, so crucial to our final understanding of the structure of matter, yet so elusive, that I have given it a nickname: the God Particle. 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…”
CERN announced the confirmation of the existence of the Higgs Boson on July 4th, 2012.
While talking about the significance of the Higgs boson, the Director-General at CERN, Fabiola Gianotti, said, “The discovery of the Higgs boson was a monumental milestone in particle physics. It marked both the end of a decades-long journey of exploration and the beginning of a new era of studies of this very special particle.” Gianotti also headed the ATLAS (A Toroidal LHC Apparatus) experiment at CERN during the discovery of the Higgs Boson.
A decade of Higgs Boson research has passed, and scientists have unraveled various mysteries linked to the particle. Recently, the physicists from CERN published multiple research papers in the journal Nature, highlighting the achievements and further goals of the Higgs Boson research. Here is an overview of the same:
The mind-boggling revelations from the Higgs Boson research
The discovery of the Higgs boson resulted from an international collaboration between the ATLAS and CMS (Compact Muon Solenoid) teams at CERN that collectively involved more than 5,500 engineers, technicians, particle physicists, students, and many other supporting members from 54 nations. Members of over 240 science institutes from across the globe participated in the search for the Higgs boson at the LHC, making it one of the largest science projects in history.
According to CERN, all of the LHC results obtained so far are based on just 5 percent of the total amount of data that the collider will deliver in its lifetime. Already, it has confirmed a number of theories and predictions of the Standard Model of Physics and also revealed new information.
Here are some of the most significant achievements of the Higgs Boson research:
- The experiments have demonstrated that the new particle has no intrinsic angular momentum or quantum spin as predicted by the Standard Model.
- Researchers observed the Higgs bosons being produced from and decaying into pairs of W or Z bosons, confirming that these particles gain their mass through their interactions with the Higgs field, as predicted by the Standard Model.
- Experiments have also demonstrated that the top quark, bottom quark, and tau lepton (the heaviest fermions) obtain their mass through interactions with the Higgs field, which was also predicted by the Standard Model. The observations confirmed the existence of an interaction, or force, called the Yukawa interaction, which is part of the Standard Model and is mediated by the Higgs boson. These interactions play a significant role in explaining the nuclear forces that hold together protons and neutrons.
- The Higgs boson’s mass was measured to be 125 billion electronvolts (GeV). While the mass of the Higgs boson is not predicted by the Standard Model, together with the mass of the heaviest known elementary particle, the top quark, and other parameters, it may determine the stability of the universe’s vacuum and explain why the universe does not collapse on itself.
- Over 60 composite particles (particles made of more than two elementary particles) predicted by the Standard Model have been discovered so far, including exotic ‘tetraquarks’ and ‘pentaquarks’.
According to CERN, “The experiments have also revealed a series of intriguing hints of deviations from the Standard Model that compel further investigation, and have studied the quark-gluon plasma that filled the universe in its early moments in unprecedented detail.” Research is also ongoing in searching for new particles beyond those predicted by the Standard Model.
According to CMS representative Luca Malgeri, “The Higgs boson itself may point to new phenomena, including some that could be responsible for the dark matter in the universe.”
The road ahead
The Higgs Boson research is still going on, and the LHC is continuously providing us with valuable data related to Higgs fields and the Higgs boson. Researchers are yet to find answers to questions including, “Does the Higgs field also give mass to the lighter fermions, or could another mechanism be at play? Is the Higgs boson an elementary or composite particle? Can it interact with dark matter and reveal the nature of this mysterious form of matter? What generates the Higgs boson’s mass and self-interaction? Does it have twins or relatives?”
Although scientists have gained a lot of information about the particle in the last 10 years, there is a lot of information that is yet to be discovered. Meanwhile, researchers at CERN are also developing plans for a new collider, dubbed the Future Circular Collider, which would be 100 km (62-mile) in circumference — considerably larger than the 27 km LHC. Once up and running, the FCC will be able to spit out huge quantities of Higgs bosons, allowing scientists to map the way these particles interact with other matter.
Current plans are for the FCC to be built in stages. The tunnel will initially house an electron-positron device that collides electrons with their antimatter counterpart, the positron. This will allow scientists to study specific phenomena associated with the four heaviest particles, including the Higgs boson, and help identify exactly how the Standard Model differs from reality.
The same instrument would then be repurposed to build a proton-proton collider that will operate at 100 teraelectronvolts (TeV) energy, potentially opening up the discovery of new particles.
It seems that the research has just begun.