The distinguished theoretical physicist and Nobel laureate, Peter Higgs, who significantly contributed to the field of particle physics with his proposal of the Higgs boson, passed away on April 8th at the age of 94. Edinburgh University announced his passing, stating that he succumbed to a brief illness.
Who is Peter Higgs?
Peter Higgs, a British physicist, was born in Northumberland, England, on May 29, 1929. Excelling academically, particularly in chemistry during his school years, he pursued his academic journey at King’s College, University of London. There, he obtained his bachelor’s, master's, and doctorate in physics, completing his PhD in 1954. In 1960, he began lecturing at Edinburgh University in mathematical physics, transitioning into academia. From 1980 to 1996, he served as a theoretical physics professor at the same university.
Reflecting on Higgs’ legacy, Professor Sir Peter Mathieson, Principal and Vice-Chancellor of Edinburgh University, stated, “Peter Higgs was an extraordinary individual — a truly gifted scientist whose vision and imagination have enriched our understanding of the world.”
The Discovery of the Higgs boson
Higgs's relentless inquiry into the nature of particle mass led him to publish a seminal paper in 1964 proposing a mechanism explaining how particles acquire mass. Despite initial rejection by a physics journal, he persevered and revised his paper, introducing the concept of a new massive boson, later named the Higgs boson. Concurrently, François Englert and Belgian-American theoretical physicist Robert Brout also studied and published papers regarding the same mechanism independently; nevertheless, Higgs was the only one to mention the existence of a new boson. The mechanism that Higgs, Englert, and Brout uncovered is called the Brout-Englert-Higgs mechanism.
In brief, Higgs envisioned a new subatomic particle called the Higgs boson that allows other particles to obtain mass.
On July 4, 2012, a milestone was reached when scientists at the European Organization for Nuclear Research (CERN) confirmed the existence of the Higgs boson through experiments conducted at the Large Hadron Collider. With the official discovery of the Higgs boson, the standard model of particle physics, which is the most comprehensive diagram of building particles of the universe, could be completed and a huge gap could be filled. Higgs responded to this discovery with these words: “For me personally, it is just the confirmation of something I did 48 years ago, and it is very satisfying to be proved right in some way”. In recognition of their pioneering contributions to the theory behind the Higgs boson, Peter Higgs and François Englert were jointly awarded the Nobel Prize for Physics in 2013.
Why is the Higgs Boson important?
Also referred to as the “God Particle,” the Higgs boson was initially theorized by physicist Peter Higgs and named after him, although Higgs disliked the term “God Particle” as an atheist. According to CERN, the Higgs boson’s mass equals 125 billion electron volts; in other words, it is 130 times heavier than a proton. The Higgs Boson is the only fundamental particle without spin.
As suggested in 1964, the Higgs field is a field that fills and comprises the universe, imparting mass to elementary particles, and the Higgs Boson is a wave within this field. Notably, the validation of the Higgs Boson automatically proves the existence of the Higgs field.
At the beginning of the universe approximately 13.8 billion years ago, particles lacked mass and traveled at light speed. According to the Brout-Englert-Higgs mechanism, these massless particles acquired their mass by interacting with the Higgs field. Unlike photons, which evade interaction with the Higgs field, they remain devoid of mass. The strength of interaction correlates with a particle's mass, thereby rationalizing the varied masses of elementary particles, encompassing electrons, quarks, and bosons.
Brout-Englert-Higgs Mechanism Explained
In the 1960s, physicists began utilizing quantum field theory to study the weak nuclear force, a fundamental force accountable for the radioactive decay of atoms. This force possesses the capability to transform one type of quark into another, enabling the conversion of a neutron into a proton and vice versa. Despite its name suggesting inferior strength compared to the strong nuclear force, it surpasses gravity in magnitude.
Moreover, quantum field theory allows the representation of particles by waves in the field, for example, with a photon being described by a wave in an electromagnetic field.
When particles interact with each other, they exchange a boson, which is defined as the force carrier particle. For instance, a photon, the force carrier of the electromagnetic field, is exchanged between two electrons, and W and Z bosons are the force carriers of the weak force.
Considering the fact that the weak force is strong in short interactions and weak in long interactions, scientists infer that its bosons should have mass. That’s when an essential issue arises with the quantum field theory: it could not be applied to the weak nuclear force because it did not let W and Z bosons have mass. Specifically, as theory indicates, these bosons should not have mass because otherwise, the symmetry rule would be broken, and the theory would not function.
The solution proposed by Higgs, Englert, and Brout consists of two main elements: a new quantum field known as the Higgs field and a spontaneous symmetry-breaking mechanism. According to their theory, the universe initially contained a symmetric but unstable Higgs field. Following the Big Bang, this symmetry was broken, yet the equations remained symmetrical, allowing for the formation of W and Z bosons. Subsequently, by interacting with the Higgs field, other elementary particles attained mass. That is to say, the Brout-Englert-Higgs mechanism presents how W and Z bosons have mass while maintaining the symmetry principle. Additionally, it probes how particles got mass, tracing back to the very beginning of the universe.
Every particle can be described as a wave in the quantum field, with the Higgs boson being associated with the Higgs field. Put simply, the Higgs boson serves as the carrier particle of the Higgs field, granting mass to all elementary particles.
In summary, as the provider of mass to particles, stars, and planets, the Higgs boson holds paramount importance. Without it, nothing would possess mass, hence its nickname, the “God Particle,” signifying its significance not only in the quantum realm but also in the evolution of the universe and the existence of all living things.
In conclusion, Nobel-winning theoretical physicist Peter Higgs's physical passing on April 8th, 2024, does not diminish his profound impact on particle physics. His groundbreaking research and discovery of the Higgs boson ensure an enduring legacy, inspiring generations of young scientists and leaving an indelible mark on humanity as a whole.