ISSN:
1434-6052
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract A new method of analysis of the photon structure functionF 2 γ (x, Q 2 ) is presented. It is a generalisation of Rossi's ansatz for generating regularised solutions of the inhomogeneous Altarelli-Parisi equations which enables initial conditions in theQ 2 evolution to be incorporated. Its equivalence to the normal solution is demonstrated. It is applied in a phenomenological analysis of the data on the structure functionF 2 γ . It is found that the recent TPCF 2 γ data in the range 0.3〈Q 2〈1.6 GeV2 cannot be used as a starting point for a perturbative QCD analysis, despite being well described by the vector meson dominance model (VMD) and exhibiting scaling. This conclusion invalidates previous discussions of the effect of the regularisation of the asymptotic point-like QCD prediction on the sensitivity ofF 2 γ to the QCD mass scale Λ, because they incorporated VMD assumptions in the perturbative region. A perturbative QCD analysis using higherQ 2 data as a starting point is presented but here the initial conditions necessarily involve more assumptions, and starting the evolution at a higherQ 2 involves an inevitable decrease in the sensitivity to Λ.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01475792
