相关论文: Possible indication to the QCD evolution of double…
We examine present data for double parton scattering at LHC and discuss their energy dependence from its earliest measurements at the ISR. Different models for the effective cross-section are considered and their behavior studied for a…
We perform a global parton analysis of deep inelastic and related hard-scattering data, including ${\cal O}(\alpha_{\rm QED})$ corrections to the parton evolution. Although the quality of the fit is essentially unchanged, there are two…
We investigate the positivity of double parton distributions with a non-trivial dependence on the parton colour. It turns out that positivity is not preserved by leading-order evolution from lower to higher scales, in contrast to the case…
Some non linear, second order QED processes in the presence of intense plane electromagnetic waves are investigated. Analytic expressions with general kinematics are derived for Compton scattering and $e^+e^-$ pair production in a…
We investigate the Q^2 evolution of parton distributions at small x values, obtained in the case of flat initial conditions. The results are in excellent agreement with deep inelastic scattering experimental data from HERA.
We present an improved determination of the proton structure functions $F_{2}$ and $xF_{3}$ from the CCFR $\nu $-Fe deep inelastic scattering (DIS) experiment. Comparisons to high-statistics charged-lepton scattering results for $F_{2}$…
Double parton distribution functions (dPDFs) represent a tool to explore the 3D partonic structure of the proton. They can be measured in high energy proton-proton and proton nucleus collisions and encode information on how partons inside a…
We present a new expansion scheme to compute the rate for parton splittings in dense and finite QCD media. In contrast to the standard opacity expansion, our expansion is performed around the harmonic oscillator whose characteristic…
A revised formula for the inclusive cross section for double parton scattering in terms of the modified collinear two-parton distributions extracted from deep inelastic scattering is suggested. The possible phenomenological issues are…
We discuss possibilities of measurement of deeply virtual Compton scattering amplitudes via different asymmetries in order to access the underlying skewed parton distributions. Perturbative one-loop coefficient functions and two-loop…
We give a description of double parton scattering with measured transverse momenta in the final state, extending the formalism for factorisation and resummation developed by Collins, Soper and Sterman for the production of colourless…
New methods have been developed for extracting the parameters of diffraction scattering amplitude, $\sigma_{tot}$ and $\rho=Re F_N/Im F_N$, from experimental data. The latter determines these parameters with less errors and without the…
The cross section for the diffractive deep-inelastic scattering process ep -> e X p is measured, with the leading final state proton detected in the H1 Forward Proton Spectrometer. The data sample covers the range x_pom<0.1 in fractional…
Double parton distribution functions (dPDFs), entering the double parton scattering (DPS) cross section, are unknown fundamental quantities encoding new interesting properties of hadrons. Here, the pion dPDFs are investigated within…
We summarize recent results on the evolution of unpolarized parton densities and deep-inelastic structure functions in massless perturbative QCD. Due to last year's extension of the integer-moment calculations of the three-loop splitting…
We re-analyze the data of the elastic electron proton scattering to look for model-independent evidence of the two-photon-exchange (TPE) effect. In contrast to previous analyses, TPE effect is parametrized in forms which are free of…
The infrared divergences of QCD scattering amplitudes can be derived from an anomalous dimension \Gamma, which is a matrix in color space and depends on the momenta and masses of the external partons. It has recently been shown that in…
We extract two-photon exchange amplitudes for the elastic electron-proton scattering at Q^2=2.5 GeV^2 from the unpolarized cross-section and recent polarization transfer measurements. There are three independent amplitudes, but only one of…
Applications of perturbative QCD to deeply virtual Compton scattering and hard exclusive meson electroproduction processes require a generalization of usual parton distributions for the case when long-distance information is accumulated in…
A measurement is made of the cross section for the process ep --> eXY in deep-inelastic scattering with the H1 detector at HERA. The cross section is presented in terms of a differential structure function F_2^D(3)(x_P,beta,Q^2) of the…