The Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGLAP) evolution equations are equations in
QCD
In theoretical physics
Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain, and predict List of natural phenomena, natural phenomena. This is in ...
describing the variation of
parton distribution functions with varying energy scales.
Experimentally observed scaling violation in
deep inelastic scattering
In particle physics, deep inelastic scattering is the name given to a process used to probe the insides of hadrons (particularly the baryons, such as protons and neutrons), using electrons, muons and neutrinos. It was first attempted in the 196 ...
is important evidence for the correctness of the equations and of QCD in general.
The equations were first published in the western world by
Guido Altarelli and
Giorgio Parisi
Giorgio Parisi (born 4 August 1948) is an Italian theoretical physicist, whose research has focused on quantum field theory, statistical mechanics
In physics, statistical mechanics is a mathematical framework that applies statistical methods ...
in 1977, and so are still sometimes called the Altarelli–Parisi equations. Only later did it become known that an equivalent formula had been published in Russia by in 1977, and by
Vladimir Gribov
Vladimir Naumovich Gribov (Russian Влади́мир Нау́мович Гри́бов; March 25, 1930August 13, 1997) was a prominent Russian theoretical physicist, who worked on high-energy physics, quantum field theory and the Regge theory o ...
and
Lev Lipatov in 1972.
[V. N. Gribov, L. N. Lipatov. ''Sov. J. Nucl. Phys.'' 15:438 (1972).]
The DGLAP QCD evolution equations are widely used in global determinations of
parton distributions, like those from the
CTEQ or
NNPDF collaborations.
See also
*
Jet (particle physics)
A jet is a narrow cone of hadrons and other particles produced by the hadronization of quarks and gluons in a particle physics or heavy ion experiment. Particles carrying a color charge, i.e. quarks and gluons, cannot exist in free form becaus ...
*
HERA
In ancient Greek religion, Hera (; ; in Ionic Greek, Ionic and Homeric Greek) is the goddess of marriage, women, and family, and the protector of women during childbirth. In Greek mythology, she is queen of the twelve Olympians and Mount Oly ...
*
APFEL (Software)
References
Further reading
External links
* Guido Altarelli (2009
QCD evolution equations for parton densities Scholarpedia, 4(1):7124.
Quantum chromodynamics
{{particle-stub