Parton (particle physics)

In particle physics, the late 1960s, the partons were hypothetical elementary particles that constitute the constituents of the hadrons in the " parton model" of the strong interaction. The name goes back to the physicist Richard Feynman. In the 1970s it was shown with the theory of quantum chromodynamics ( QCD) that hadrons consist of the postulated by Murray Gell-Mann quarks - Feynman was outvoted in the naming, now we speak of quarks and gluons as constituents of a hadron.

QCD describes the interaction in nuclei detail than the parton model, but the latter is still used to describe certain aspects of the interactions at very small distances.

Parton Distribution Functions

The parton distribution functions ( parton distribution functions, PDF) give the probability of finding a particle with a certain longitudinal momentum fractions to find x and the momentum transfer Q2 in a hadron. The parton distribution functions can not be calculated perturbatively due to nonperturbative effects of QCD. Therefore, the well-known parton distribution functions derived ( and because of limitations of the lattice gauge theory ) from experimental data.

There are multiple, determined by various groups around the world, the distribution functions. The most important are:

  • CTEQ, from the CTEQ Collaboration
  • GRV, M. Luck, E. Reya and A. Vogt
  • MRST, AD Martin, RG Roberts, WJ Stirling and RS Thorne

Swell

Parton Distribution Functions

  • M. Luck, E. Reya, A. Vogt, " Dynamical Parton Distributions Revisited ", Eur Phys. J. C5, 461-470 (1998).
  • AD Martin et al., " Parton distributions Incorporating QED Contributions", Eur Phys. J. C39, 155 161 ( 2005).
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