Color transparency[1] [2] is a phenomenon observed in high-energy particle physics, where hadrons (particles made of quarks such as a proton or mesons) created in a nucleus propagate through that nucleus with less interaction than expected.
Color transparency arises from the behavior of quarks inside hadrons.
This reduced scattering, or transparency, is attributed to the fact soon after the hadron is created, the gluon cloud surrounding the quarks is more compact, viz the effective size of the singlet object is small, leading to reduced interaction.
This effect is observed in experiments involving high-energy electron scattering off nuclei, where the transparency increases with increasing energy of the incoming particles, or more precisely with the 4-momentum transfer
The radius is small because the quarks are close to each other, making their external color fields to cancel, much like the electric field of an electric dipole vanishes at distances much larger than the dipole size.
[4] [5] The above interpretation is in the partonic language, which uses quarks and gluons as the degrees of freedom.
Due to the quark-hadron duality, or parton-hadron duality,[6] meaning that all QCD predictions can be expressed using a hadronic basis, color transparency can also be described using hadronic degrees of freedom.
The experiment ran from June 1988 to January 1992 and collided high-energy (500 GeV) pions onto carbon and platinum nuclei.
The experiment observed evidence of color transparency in the production of vector mesons, such as
Color transparency is important because it provides valuable insights into the strong interaction.
[1] Additionally, color transparency has implications for nuclear physics and the structure of atomic nuclei.
By studying how particles interact with nuclei at high energies, one learns more about the distributions of quarks and gluons within nucleons and how they are affected by the surrounding nuclear environment.