(Noun. /STAN-derd MOD-l/ )
by Clark Hickman
What does It mean?
The Standard Model (SM) is the theory that best describes the physics of the universe based on the evidence gathered to date. The model divides the fundamental particles of the universe – that is, particles that cannot be broken down into smaller constituents – into three classes. Quarks are the fundamental particles that make up hadrons. The most common hadrons are protons and neutrons, which can combine to form the nucleus of atoms that make up everyday matter. The third constituent of the atom, the electron, is the lightest and most stable particle in the class of leptons. Finally, gauge bosons can be thought of as “force carriers” in that they describe how the other particles can interact with each other through three of the four fundamental forces (electromagnetism, strong and weak nuclear force, but NOT gravity). Completing the picture, the Higgs boson gives the other fundamental particles their mass. The Higgs was theorized in the 1960s during the development of the SM, but was only discovered in 2012 once researchers had built a collider large enough to create it.
While the SM has been physics’ most successful theory to date, even predicting some of the fundamental particles before they were experimentally discovered, it is still noticeably lacking in other areas. For one, it does not have an explanation for gravity, a force that we know plays an important role at the scale of humans and planets but is very weak (compared to the other forces) at the fundamental particle scale. Additionally, the SM has no explanation for dark matter or dark energy, which astrophysicists have shown makes up ~95% of the universe today. This has led many researchers to search for scientific evidence proving (or disproving) Beyond the Standard Model (BSM) theories that expand on the model to explain some of these discrepancies.
All of the known matter in the universe can be described by the fundamental particles of the Standard Model. Image Source
How do I use it in a sentence?
The Standard Model is one of the most successful scientific theories to date, yet scientists know that it is an incomplete picture at best because it fails to reconcile the physics of very small particles (quantum mechanics) with that of very large objects (gravity and general relativity).
Etymology
The “Standard Model” moniker was first coined in the early 1970s to describe the emerging theory underlying major progress in the fields of quantum chromodynamics and electroweak theory made in the 1960s and 1970s. The Standard Model framework combined these theoretical and experimental advancements into one unifying and consistent theory.
Related Terms
Quantum mechanics
Fields of Study in which this word is commonly used
Particle physics
Astrophysics
