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arXiv · 0902.3086

Parton distributions in the virtual photon target up to NNLO in QCD

Takahiro Ueda·Ken Sasaki·Tsuneo Uematsu
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Abstract

Parton distributions in the virtual photon target are investigated in perturbative QCD up to the next-to-next-to-leading order (NNLO). In the case $Λ^2 \ll P^2 \ll Q^2$, where $-Q^2$ ($-P^2$) is the mass squared of the probe (target) photon, parton distributions can be predicted completely up to the NNLO, but they are factorisation-scheme-dependent. We analyse parton distributions in two different factorisation schemes, namely $\bar{\rm MS}$ and ${\rm DIS}_γ$ schemes, and discuss their scheme dependence. We show that the factorisation-scheme dependence is characterised by the large-$x$ behaviours of quark distributions. Gluon distribution is predicted to be very small in absolute value except in the small-$x$ region.

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Takahiro Ueda, Ken Sasaki, Tsuneo Uematsu. 2009-05-26. Parton distributions in the virtual photon target up to NNLO in QCD. https://doi.org/10.1140/epjc%2Fs10052-009-1062-7

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