Robin Devenish and Amanda Cooper-Sarkar
- Published in print:
- 2003
- Published Online:
- January 2010
- ISBN:
- 9780198506713
- eISBN:
- 9780191709562
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198506713.003.0004
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
The QCD improved parton model provides the foundation on which all the remaining chapters are based. This chapter begins by covering the key ideas: tree level QCD Compton and boson-gluon fusion ...
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The QCD improved parton model provides the foundation on which all the remaining chapters are based. This chapter begins by covering the key ideas: tree level QCD Compton and boson-gluon fusion processes give rise to characteristic gluonic ‘radiative corrections’ to the QPM; infrared singularities are absorbed by renormalizing the parton densities, which thus become Q2 dependent and no longer satisfy exact Bjorken scaling. The next section covers the DGLAP evolution equations, which enable the Q2 dependence to be calculated perturbatively using ‘splitting functions’. To give an insight into the effect of these equations, some simple numerical examples are given in the following section. The relationship between the more formal Operator Product Expansion method outlined in the previous chapter and the DGLAP approach is indicated. The last three sections comment on: higher twist; the extension of the DGLAP formalism to accommodate heavy quarks; and the extension of the DGLAP formalism to higher orders.Less
The QCD improved parton model provides the foundation on which all the remaining chapters are based. This chapter begins by covering the key ideas: tree level QCD Compton and boson-gluon fusion processes give rise to characteristic gluonic ‘radiative corrections’ to the QPM; infrared singularities are absorbed by renormalizing the parton densities, which thus become Q2 dependent and no longer satisfy exact Bjorken scaling. The next section covers the DGLAP evolution equations, which enable the Q2 dependence to be calculated perturbatively using ‘splitting functions’. To give an insight into the effect of these equations, some simple numerical examples are given in the following section. The relationship between the more formal Operator Product Expansion method outlined in the previous chapter and the DGLAP approach is indicated. The last three sections comment on: higher twist; the extension of the DGLAP formalism to accommodate heavy quarks; and the extension of the DGLAP formalism to higher orders.
