On July 4, 2012 , the existence of the Higgs boson was confirmed by the European Organization for Nuclear Research (CERN), a subatomic particle essential to understand the world around us.
1. Why was the discovery of the Higgs boson so important?
Because it contains the answer to the following question: how does nature decide which particles to assign mass to and which ones not? All the elementary particles that make up matter (six leptons and six quarks) have mass. However, others such as the photon, responsible for the electromagnetic force, have no mass. The presence or absence of mass could be given by the Higgs boson, whose existence was proposed in the 1960s, and its discovery was confirmed on July 4, 2012 at CERN.
2. What is the Higgs field?
To explain why some particles have mass and others do not, the British physicist Peter Higgs (and simultaneously but independently, also Francois Englert, Robert Brout, Gerald Guralnik, Dick Hagen and Tom Kibble) postulated in the 1960s a mechanism that it is known as the “Higgs field”. Just as the photon is the fundamental component of light, the Higgs field requires the existence of a particle that composes it, which physicists call “Higgs boson”. The Higgs field is a kind of continuum that spans all of space, made up of countless numbers of Higgs bosons . The mass of the particles would be caused by a kind of “friction” with the Higgs field, so that the lighter particles would move through this field easily while the heavier ones would do it with greater difficulty.
3. Who coined the name “God particle”?
It was the Nobel Prize in Physics Leon Lederman, who wrote the book “The Goddamn Particle”. But his publisher thought that this name was not commercial enough, so they changed it to “The God Particle”.
However, many researchers prefer the nickname of “the particle of the champagne bottle”, alluding to the anecdote according to which the physicist David J. Miller won a bottle of champagne in 1993 offered by the British minister of science William Waldegrave, who He offered it as a “prize” to whoever was able to explain what the Higgs boson was.
4. Why was the LHC used to find the Higgs boson?
The confirmation of the existence of the Higgs boson was the work of the Large Hadron Collider (LHC) , the world’s largest and most powerful particle accelerator operated by the European Organization for Nuclear Research (CERN) at the Franco-Swiss border, near Geneva. Inside CERN’s accelerator ring, protons collide with each other at close to the speed of light. According to the calculations, the Higgs bosons should occur in frontal collisions between protons of energies of the order of 20 TeV. After all, the higher the energy of the colliding particles, the more mass the resulting particles will have, according to Einstein’s famous equation E = mc2. However, the Higgs boson could not be detected directly, since once it is produced it disintegrates almost instantaneously, giving rise to other more common elementary particles (photons, muons, electrons …) that are detected in the LHC.
5. What do the “sigmas” that physicists talk about mean?
The Higgs boson cannot be observed directly because its lifetime is too short. At the end of its life, it decays and transforms into other particles, which are what the detectors observe. For example, in two photons. But many other processes also generate two photons, so scientists have to compare the number of “two-photon events” and compare it to what is expected for a given particle.
To claim the paternity of a discovery, physicists need to have an excess of significant collisions , which requires another magnitude: the standard deviation or the “number of sigmas”, which establishes the statistical significance of that discovery.
In making the announcement about the Higgs boson, Fabiola Gianotti said: “We have observed clear signs of a new particle at the five sigma level in the region of mass around 126 gigaelectronvolts (GeV). The five sigma value is the minimum level accepted by the scientific community to confirm the discovery of a particle, and indicates that the probability that what we are seeing is the result of chance is smaller than a few parts in ten million (or that the confidence is 99.99994 %).
