Quantum chromodynamics

force binding particles within the atomic nucleus

theory of strong interactions, a fundamental force describing the interactions between quarks and gluons, which make up hadrons such as the proton, neutron and pion

force between nucleons

property of quarks and gluons that is related to the particles’ strong interactions in the theory of quantum chromodynamics

one third of the difference between the number of quarks and antiquarks in a system

type of elementary particles occurring in the Standard Model

An axion () is a hypothetical elementary particle originally theorized in 1978 independently by Frank Wilczek and Steven Weinberg as the Goldstone boson of Peccei–Quinn theory, which had been proposed in 1977 to solve the strong CP problem in quantum chromodynamics (QCD). If axions exist and have low mass within a specific range, they are of interest as a possible component of cold dark matter.

physical phenomenon in which the vacuum expectation value of a field is not invariant under a symmetry of the action, so that a symmetry present at high temperatures is broken at low temperatures

neutral composite particle with some components not found in normal atoms

phenomenon preventing hadrons (quarks bound by the strong force using gluons) from being separated into free individual quarks

In particle physics, a tetraquark is an exotic meson composed of four valence quarks. A tetraquark state has long been suspected to be allowed by quantum chromodynamics, the modern theory of strong interactions. A tetraquark state is an example of an exotic hadron that lies outside the conventional quark model classification. A number of different types of tetraquark have been observed.

generalization of electric charge (EM) adding color charge (QCD), mass-energy (gravitation), etc.; sometimes considered same as its charge quantum number

phenomenon in certain quantum systems in which the coupling constant becomes small at high energy scales

In particle physics, a glueball (also gluonium, gluon-ball) is a hypothetical composite particle. It consists solely of gluons, without valence quarks. Such a state is possible because gluons carry color charge and experience the strong interaction between themselves. Glueballs are extremely difficult to identify in particle accelerators, because they mix with ordinary meson states. In pure gauge theory, glueballs are the only states of the spectrum and some of them are stable.

phenomenon applied in physics

type of unphysical field in quantum field theory which provides mathematical consistency

pointlike constituent (quark or gluon) of hadrons observable during high-energy hadron collisions that cause showers

In particle theory, the skyrmion () is a topologically stable field configuration of a certain class of non-linear sigma models. The term was first used in 1979 to name a model of the nucleon by proposed in 1961 by Tony Skyrme. As a topological soliton in the pion field, it has the remarkable property of being able to model, with reasonable accuracy, multiple low-energy properties of the nucleon, simply by fixing the nucleon radius. It has since found application in solid-state physics, as well as having ties to certain areas of string theory.

set of matrices useful in studying the strong force

A strangelet (pronounced ) is a hypothetical particle consisting of a bound state of roughly equal numbers of up, down, and strange quarks. An equivalent description is that a strangelet is a small fragment of strange matter, small enough to be considered a particle. The size of an object composed of strange matter could, theoretically, range from a few femtometers across (with the mass of a light nucleus) to arbitrarily large. Once the size becomes macroscopic (on the order of meters across), such an object is usually called a strange star. The term "strangelet" originates with Edward Farhi a

An instanton (or pseudoparticle) is a notion appearing in theoretical and mathematical physics. An instanton is a classical solution to equations of motion with a finite, non-zero action, either in quantum mechanics or in quantum field theory. More precisely, it is a solution to the equations of motion of the classical field theory on a Euclidean spacetime.

number of theorized phases of matter whose degrees of freedom include quarks and gluons

In physics, the pomeron is a Regge trajectory — a family of particles with increasing spin — postulated in 1961 to explain the slowly rising cross section of hadronic collisions at high energies. It is named after Isaak Pomeranchuk.

gauge-invariant observable obtained from the holonomy of the gauge connection around a given loop

Millennium Prize Problem

quantum chromodynamics on a lattice

principle in hadron decay rates

four-vector field characterizing the propagation of gluons in the strong interaction between quarks

proposed resolution to the strong CP problem

intersection of nuclear physics and high-energy physics

Hadronization (or hadronisation) is the process of the formation of hadrons out of quarks and gluons. There are two main branches of hadronization: quark-gluon plasma (QGP) transformation and colour string decay into hadrons. The transformation of quark-gluon plasma into hadrons is studied in lattice QCD numerical simulations, which are explored in relativistic heavy-ion experiments. Quark-gluon plasma hadronization occurred shortly after the Big Bang when the quark–gluon plasma cooled down to the Hagedorn temperature (about 150 MeV) when free quarks and gluons cannot exist. In string bre

exotic atom consisting of a negatively charged kaon orbiting a proton

a method of analyzing scattering in quantum physics

type of matter theorized to exist in atomic nuclei traveling near the speed of light

equations describing parton distribution functions in QCD

formulation to quantize gauge field theories in physics

second order tensor field characterizing the gluon interaction between quarks

phenomenon in quark matter where matter carries color charge without loss

particular perturbative analysis of quantum field theories

quantum electrodynamics in 1+1 dimensions