@article{oai:ynu.repo.nii.ac.jp:00003965,
 author = {Ueda, Takahiro and Sasaki, Ken and Uematsu, Tsuneo},
 issue = {11},
 journal = {Physical review D},
 month = {Jun},
 note = {application/pdf, We investigate the unpolarized virtual photon structure functions F2γ(x,Q2,P2) and FLγ(x,Q2,P2) in perturbative QCD for the kinematical region Λ2≪P2≪Q2, where -Q2 (-P2) is the mass squared of the probe (target) photon and Λ is the QCD scale parameter. Using the framework of the operator product expansion supplemented by the renormalization group method, we derive the definite predictions for the moments of F2γ(x,Q2,P2) up to the next-to-next-to-leading order (NNLO) (the order ααs) and for the moments of FLγ(x,Q2,P2) up to the next-to-leading order (NLO) (the order ααs). The NNLO corrections to the sum rule of F2γ(x,Q2,P2) are negative and found to be 7%–10% of the sum of the LO and NLO contributions, when P2=1  GeV2 and Q2=30∼100  GeV2 or P2=3  GeV2 and Q2=100  GeV2, and the number of active quark flavors nf is three or four. The NLO corrections to FLγ are also negative. The moments are inverted numerically to obtain the predictions for F2γ(x,Q2,P2) and FLγ(x,Q2,P2) as functions of x.},
 title = {Virtual photon structure functions to the next-to-next-to-leading order in QCD},
 volume = {75},
 year = {2007}
}