What if I claimed the entirety of the cosmos can be formed from 12 elementary particles governed by four fundamental forces?
That’s exactly what the standard model of particle physics posits. Since the early 1970s, both experimental and theoretical particle physicists have been testing the consistency of this model, which, if accurate, would describe the fundamental structure of all matter in the universe.
Up until July, the model was extremely effective in understanding all 12 elementary particles in relation to three of four fundamental forces. (Gravity has been historically pesky.) In addition, physicists armed with the standard model ably predicted the existence of certain particles years before they were empirically discovered, thus lending the theory further credence.
Six quarks—up and down, charm and strange, top and bottom—make up protons and neutrons, while six leptons—the electron, muon, tau and their respective neutrinos—are the other basic constituents of matter. Force-carrying particles known as bosons—the photon, gluon and W and Z bosons—correspond to the electromagnetic, strong and weak (nuclear) forces. The discovery of these particles in the late 20th century helped substantiate the standard model. Yet despite this progress, physicists still struggled to explain the origin of mass in our universe.
That struggle (may have) ended on July 4. Researchers at CERN, the European Organization for Nuclear Research, announced the discovery of a particle consistent with the Higgs boson, which is theorized to have created the Higgs field during the early stages of our universe and can explain how matter attains mass.
In 1964, Peter Higgs and other particle physicists suggested that all particles were inherently massless following the Big Bang. Only after the universe cooled down to a critical temperature did the “Higgs field” form, and it was responsible for imparting mass to the 12 fundamental particles (except the photon). Essentially, the more a particle interacts with the Higgs field, the heavier it becomes.
Though theoretically sound, the Higgs mechanism was untestable until the building of the Large Hadron Collider in Geneva, Switzerland. Even then, the Higgs boson only lasts for fractions of a second before it decays, so measuring it amidst post-collision debris was not easy. Therefore, its highly probable discovery with a statistical significance of 4.9 sigma (meaning there is a one-in-two-million chance the signal was due to background noise) is truly a milestone in modern physics. Furthermore, on Aug. 1, CERN stated that even stronger evidence, and a two-in-one-billion chance the signal was caused by background processes, has identified the newly discovered particle as the Higgs boson.
Implications of finding this notoriously elusive particle are wide-reaching. In addition to explaining the origin of mass, the Higgs boson would complete the standard model by unifying the weak and electromagnetic force. Through this unification, electricity, magnetism, light and some types of radioactivity would become manifestations of one underlying force known as the electroweak force. Moreover, if this Higgs-like particle were actually the Higgs boson, then the universe itself would open up to a whole new realm of discovery. The Higgs boson could be to 2012 what the electron was to 1897.
Honestly, it’s too soon to assess the lasting significance of these exciting times in particle physics, especially as CERN scientists continue to scrutinize their findings. However, given the data publicly released thus far, I’m willing to greet this long-awaited “God particle” by its appropriate name. Hello, Higgs.