Related papers: Higher twists in the pion structure function
Inspired by recent measurements with the CLAS detector at Jefferson Lab, we perform a self-consistent analysis of world data on the proton structure function g1 in the range 0.17 < Q2 < 30 (GeV/c)**2. We compute for the first time low-order…
We apply the background field method to calculate the moments of the pion two-particles twist-3 distribution amplitude (DA) $\phi_p(\xi)$ in QCD sum rules. In this paper,we do not use the equation of motion for the quarks inside the pion…
Recent precision spin structure data from Jefferson Lab have significantly advanced our knowledge of nucleon structure in the valence quark (high-$x$) region and improved our understanding of higher-twist effects, spin sum rules and…
We calculate the leading twist valence quark distribution in the pion in the framework of QCD sum rules with nonlocal condensates. Particular attention has been paid to the correct account for the bilocal power corrections.
We present a quantitative analysis of the electromagnetic pion form factor in the light-cone sum rule approach, including radiative corrections and higher-twist effects. The comparison to the existing data favors the asymptotic profile of…
We present the most accurate calculation for the pion and kaon electromagnetic form factors in the framework of perturbative QCD, where the power corrections up to twist-4 of the meson distribution amplitudes and the next-to-leading-order…
The leading chiral contributions to the quark and gluon components of the proton spin are calculated using heavy-baryon chiral perturbation theory. Similar calculations are done for the moments of the generalized parton distributions…
Quark-hadron duality is studied in a systematic way for polarized and unpolarized structure functions, by taking into account all the available data in the resonance region. In both cases, a precise perturbative QCD based analysis of the…
In this paper we calculate the power corrections to the pion transition form factor within the framework of perturbative QCD approach on the basis of $k_T$ factorization. The power suppressed contributions from higher twist pion wave…
Available analyses on moments of the spin structure function g_1 use different methods and are barely consistent with each other. We present a higher twist analysis of Gamma_1^p using a method consistent with the studies of Gamma_1^n and…
Power corrections to the Q**2 behavior of the Nachtmann moments of the proton polarized structure function g1p are investigated at large Bjorken-x by developing a phenomenological fit of both the resonance (including the photon point) and…
We study the non-forward matrix elements of twist-2 QCD light-ray operators and their representations in terms of skewed and double distributions, considering the pion as well as the nucleon. We point out the importance of explicitly…
The higher twist corrections $h^N(x)/Q^2$ to the spin dependent proton and neutron structure functions $g_1^N(x, Q^2)$ are extracted in a model independent way from experimental data on $g_1^N$ and found to be non-negligible. It is shown…
We present an analysis to extract kaon parton distribution functions (PDFs) for the first time using meson-induced Drell-Yan and quarkonium production data. Starting from the statistical model first developed for determining the partonic…
Pion transition form factor for the process $\gamma*\gamma*\to \pi^0$ at space-like values of photon momenta is calculated within the effective quark-meson model with the interaction induced by instanton exchange. The leading and…
We present an extraction of the lowest three moments of the proton longitudinal structure function F_L from world data between Q^2 = 0.75 and 45 (GeV/c)^2. The availability of new F_L data at low Bjorken x from HERA and at large x from…
The electromagnetic form factor of the pion is calculated in the "point-form" of relativistic quantum mechanics using simple, phenomenological wave functions. It is found that the squared charge radius of the pion is predicted one order of…
We map the distribution of unpolarized quarks inside a unpolarized pion as a function of the quark's transverse momentum, encoded in unpolarized Transverse Momentum Distributions (TMDs). We extract the pion TMDs from available data of…
Existing pion+nucleus Drell-Yan and electron+pion scattering data are used to develop ensembles of model-independent representations of the pion generalised parton distribution (GPD). Therewith, one arrives at a data-driven prediction for…
We describe the present status of the pion distribution amplitude as it originated from two sources: (i) a nonperturbative approach, based on QCD sum rules with nonlocal condensates and (ii) a NLO QCD analysis of the CLEO data on…