Related papers: Spin-Dependent Structure Functions of Real and Vir…
The implications of the positivity constraint on the presently unknown polarized structure function of the photon, $g_1^{\gamma}(x,Q^2)$, are studied in detail. In particular the non-trivial consequences of this constraint,…
Polarized photon structure can be studied in the future polarized $e^{+}e^{-}$ colliding-beam experiments. We investigate the spin-dependent structure function of the virtual photon $g_1^{\gamma}(x,Q^2,P^2)$, in perturbative QCD for…
We study the three positivity constraints among the eight virtual photon structure functions, derived from the Cauchy-Schwarz inequality and which are hence model-independent. The photon structure functions obtained from the simple parton…
We calculate the spin dependent structure function of the polarized virtual photon $g_1^{\gamma}(x,Q^2,p^2)$, especially its hadronic part, using the OPE in the inverse powers of the target photon virtuality. Some model is accepted to…
Spin dependent structure function $g_1^{\gamma}(x,Q^2)$ of the polarised photon is analysed within the formalism based upon the unintegrated spin dependent parton distributions incorporating the LO Altarelli-Parisi evolution and the double…
The unpolarized virtual photon structure functions $F_2^\gamma(x,Q^2,P^2)$ and $F_L^\gamma(x,Q^2,P^2)$ are investigated in perturbative QCD for the kinematical region $\Lambda^2 \ll P^2 \ll Q^2$, where $-Q^2(-P^2)$ is the mass squared of…
We show that the first moment of the spin-dependent structure function $g_1^{\gamma}(x,Q^2)$ of a real photon vanishes independent of the momentum transfer $Q^2$ it is probed with. This result is non-perturbative: it holds to all orders in…
We investigate the spin structure of the virtual photon beyond the leading order in QCD. The first moment of the virtual photon spin structure function $g_1^\gamma(x,Q^2,P^2)$ with QCD effects turns out to be non-vanishing in contrast to…
We investigate the transition of the polarized photon structure function $g_1^\gamma(x,Q^2,P^2)$ when the target photon shifts from on-shell ($P^2=0$) to far off-shell ($P^2\gg \Lambda^2$) region. The analysis is performed to the…
The parton content of real (P^2=0) and virtual (P^2\neq 0) transverse photons \gamma(P^2) is expressed in terms of perturbative pointlike and nonperturbative hadronic (VMD) components, employing recently updated parton distributions of…
The virtual photon structure function $g_1^{\gamma}(x,Q^2,P^2)$, which can be obtained in polarized $e^{+}e^{-}$ colliding-beam experiments, is investigated for $\Lambda^2 \ll P^2 \ll Q^2$, where $-Q^2$ ($-P^2$) is the mass squared of the…
Spin-dependent parton distributions in the polarized virtual photon are investigated in QCD up to the next-to-leading order (NLO). In the case $\Lambda^2 \ll P^2 \ll Q^2$, where $-Q^2$ ($-P^2$) is the mass squared of the probe (target)…
A next-to-leading order (NLO) QCD analysis of the spin-dependent parton distributions $\Delta f^{\gamma}(x,Q^2)$ of the longitudinally polarized photon and of its structure function $g_1^{\gamma}(x,Q^2)$ is performed within the framework of…
Recent measurements of unpolarised and polarised nucleon structure functions and F_2(gamma) are reviewed. The implications for QCD and the gluon momentum distribution are discussed. The status of the understanding of the total…
The theoretical framework for a next-to-leading order QCD analysis of the spin-dependent parton densities Delta f^{gamma}(x,Q^2) of the longitudinally polarized photon and of its structure function g_1^{gamma}(x,Q^2) is reviewed in some…
We investigate the positivity constraints for the structure functions of both virtual and real photon. From the Cauchy-Schwarz inequality we derive three positivity conditions for the general virtual photon case, which reduce, in the real…
We discuss the perturbatively calculable virtual photon structure functions. First we present the framework for analyzing the structure functions of the virtual photon and derive a first moment of $g_1^\gamma$ of the virtual photon. We then…
We generalize the sum rules for the nucleon electric plus magnetic polarizability $\Sigma=\alpha+\beta$ and for the nucleon spin-polarizability $\gamma$, to virtual photons with $Q^2>0$. The dominant low energy cross sections are…
It is shown that in the special infinite momentum frame where photon has pure transverse components at $P\rightarrow\infty$ the spin-dependent deep inelastic structure function $ g_{2}(x)$ has a reasonable interpretation in terms of…
We discuss target mass effects in the polarized virtual photon structure functions $g_1^\gamma (x,Q^2,P^2)$, $g_2^\gamma (x,Q^2,P^2)$ for the kinematic region $\Lambda^2\ll P^2 \ll Q^2$, where $-Q^2 (-P^2)$ is the mass squared of the probe…