arXiv subjects

Yoshio Kitadono

Publications and source records attributed to Yoshio Kitadono.

22 records · Page 2Linked to original sources

arXiv2010

Heavy quark effects on parton distribution functions in the unpolarized virtual photon up to the next-to-leading order in QCD

We investigate the heavy quark mass effects on the parton distribution functions in the unpolarized virtual photon up to the next-to-leading order in QCD. Our formalism is based on the QCD-improved parton model described by the DGLAP evolution equation as well as on the operator product expansion supplemented by the mass-independent renormalization group method. We evaluate the various components of the parton distributions inside the virtual photon with the massive quark effects, which are included through the initial condition for the heavy quark distributions, or equivalently from the matrix element of the heavy quark operators. We discuss some features of our results for the heavy quark effects and their factorization-scheme dependence.

hep-ph↗

arXiv2008

Heavy Quark Effects in the Virtual Photon Structure Functions

We investigate the heavy quark mass effects in the virtual photon structure functions $F_{2}^γ(x, Q^2, P^2)$ and $F_{L}^γ(x, Q^2, P^2)$ in the framework of the mass-independent renormalization group equation (RGE). We study a formalism in which the heavy quark mass effects are treated based on parton picture as well as on the operator product expansion (OPE), and perform the numerical evaluation of $F_{\rm eff}^γ(x, Q^2, P^2)$ to the next-leading order (NLO) in QCD.

hep-ph↗

arXiv2008

NNLO QCD analysis of the virtual photon structure functions

The next-to-next-to-leading order (NNLO) QCD analysis is performed for the virtual photon structure functions which can be measured in the double-tag events in two-photon processes in $e^+e^-$ collisions. We investigate the perturbative QCD evaluation of $F_2^γ(x,Q^2,P^2)$ to NNLO and $F_L^γ(x,Q^2,P^2)$ to NLO with and without taking into account the target mass effects, which are relevant for the large $x$ region. We also carry out the phenomenological analysis for the experimentally accessible effective structure function $F_{\rm eff}^γ=F_2^γ+(3/2)F_L^γ$.

hep-ph↗

arXiv2008

Target Mass Corrections for the Virtual Photon Structure Functions to the Next-to-next-to-leading Order in QCD

We investigate target mass effects in the unpolarized virtual photon structure functions $F_2^γ(x,Q^2,P^2)$ and $F_L^γ(x,Q^2,P^2)$ in perturbative QCD for the kinematical region $Λ^2 \ll P^2 \ll Q^2$, where $-Q^2(-P^2)$ is the mass squared of the probe (target) photon and $Λ$ is the QCD scale parameter. We obtain the Nachtmann moments for the structure functions and then, by inverting the moments, we get the expressions in closed form for $F_2^γ(x,Q^2,P^2)$ up to the next-to-next-to-leading order and for $F_L^γ(x,Q^2,P^2)$ up to the next-to-leading order, both of which include the target mass corrections. Numerical analysis exhibits that target mass effects appear at large $x$ and become sizable near $x_{\rm max}(=1/(1+\frac{P^2}{Q^2}))$, the maximal value of $x$, as the ratio $P^2/Q^2$ increases.

hep-ph↗