A
jet is a narrow cone of
hadrons and other particles produced by the
hadronization of a
quark or
gluon in a
particle physics or heavy
ion experiment. Particles carrying a color charge, such as quarks, cannot exist in free form because of
QCD confinement which only allows for colorless states. When an object containing color charge fragments, each fragment carries away some of the color charge. In order to obey confinement, these fragments create other colored objects around them to form colorless objects. The ensemble of these objects is called a jet. Jets are measured in
particle detectors and studied in order to determine the properties of the original quarks.