Summarizing GUTs

Summary

• Attempts to show unification of the four forces are called Grand Unified Theories (GUTs) and have been partially successful, with connections proven between EM and weak forces in electroweak theory.
• The strong force is carried by eight proposed particles called gluons, which are intimately connected to a quantum number called color—their governing theory is thus called quantum chromodynamics (QCD). Taken together, QCD and the electroweak theory are widely accepted as the Standard Model of particle physics.
• Unification of the strong force is expected at such high energies that it cannot be directly tested, but it may have observable consequences in the as-yet unobserved decay of the proton and topics to be discussed in the next tutorial. Although unification of forces is generally anticipated, much remains to be done to prove its validity.

Glossary

electroweak theory

theory showing connections between EM and weak forces

grand unified theory

theory that shows unification of the strong and electroweak forces

gluons

eight proposed particles which carry the strong force

Higgs boson

a massive particle that, if observed, would give validity to the theory that carrier particles are identical under certain circumstances

quantum chromodynamics

the governing theory of connecting quantum number color to gluons

standard model

combination of quantum chromodynamics and electroweak theory

superstring theory

a theory of everything based on vibrating strings some \({\text{10}}^{-\text{35}}\phantom{\rule{0.25em}{0ex}}\text{m}\) in length