Related papers: Pion Structure Function $F_{2}^{\pi}$ in the Valon…
Preliminary results on a measurement of the proton structure function F_2 are reported for momentum transfers squared Q^2 between 1.5~GeV^2 and 5000 GeV^2 and for Bjorken x between 5.10^{-5} and 0.32 using data collected by the HERA…
Using fragmentation functions for charged pions, charged kaons, and (anti)protons recently extracted from experimental data of e^+e^- annihilation at the Z-boson resonance and at centre-of-mass energy root(s) = 29 GeV, we perform a global…
The pion cloud is important in nuclear physics and in a variety of low-energy hadronic phenomena. We argue that it is natural to expect it to also be important in lepton-proton deep inelastic scattering and Drell-Yan studies of proton…
Using a holographic dual model of QCD, we compute the pion electromagnetic form factor F_pi(Q^2) in the spacelike momentum transfer region, as well as pion couplings to vector mesons g_rho^(n) pi pi. Spontaneous and explicit chiral symmetry…
In this talk, I focus on the quark-gluon structure of hadrons probed using high-energy hadron beams. I start with a brief review on recent major achievements in measuring parton distributions of the nucleon, pion, and kaon, with hadron…
Clear windows onto emergent hadron mass (EHM) and modulations thereof by Higgs boson interactions are provided by observable measures of pion and kaon structure, many of which are accessible via generalised parton distributions (GPDs).…
We calculate the off-forward structure function of the pion within a simple model where the size of the pion is accounted for using a momentum cut-off. Twist-two and twist-three generalized parton distributions are extracted. Relations…
We present new sets of fragmentation functions for charged pions and kaons, both at leading and next-to-leading order. They are fitted to TPC data taken at energy $\sqrt s=29$~GeV and describe excellently a wealth of other $e^+e^-$ data on…
In a model of hadrons in which the hadron wave function at low $Q^2$ is represented by a hadron-like Fock state expansion, we calculate the $\pi$ and $K$ parton distribution functions by comparing to experimental data. We show that the…
Low and high energy properties of the pion are reviewed in the framework of chiral quark models. Particular emphasis is put on the simplest version of the SU(2) NJL model as prototype. The role of gauge invariance in this kind of…
Structure function data provide insight into the nucleon quark distribution. They are relatively straightforward to extract from the world's vast, and growing, amount of inclusive lepto-production data. In turn, structure functions can be…
This research summarizes work done by myself (Nucl.Phys.{\bf A641} (1998)461), or in collaboration with R. M. Davidson (Phys.Lett.{\bf B348}(1995)163) and H. Weigel and L. Gamberg (Nucl.Phys.{\bf B560}(1999)xx). I will discuss several…
A coherent state of pions is introduced to the nonrelativistic quark model. The coherent pair approximation is employed for the pion field in order to maintain the spin-isospin symmetry. In this approximation the pion is localized in the…
Exploiting crossing symmetry, the hadron scale pion valence quark distribution function is used to predict the kindred elementary valence quark fragmentation function (FF). This function defines the kernel of a quark jet fragmentation…
In this talk I review studies of hadron structure functions in bosonized chiral quark models. Such models require regularization and I show that the two--fold Pauli--Villars regularization scheme not only fully regularizes the effective…
In order to illustrate the capabilities of COMPASS using a hadronic beam, I review some of the azimuthal asymmetries in hadronic collisions, that allow for the extraction of transversity, Sivers and Boer-Mulders functions, necessary to…
We extend the investigation of the Generalized Parton Distribution for a charged pion within a fully covariant constituent quark model, in two respects: (i) calculating the tensor distribution and (ii) adding the treatment of the evolution,…
Off-forward structure functions of the pion are investigated in twist-two and twist-three approximation. A simple model is used for the pion, which allows to introduce finite size effects, while preserving gauge invariance. Results for the…
New results on charm and beauty electroproduction from the H1 and ZEUS Collaborations at the ep collider HERA are presented. Differential cross sections are compared to a next-to-leading order QCD calculation. The heavy quark contributions,…
New results from the H1 and ZEUS collaborations on the measurement of cross-sections at very high Q^2 (up to 25000 GeV^2) and on the proton structure function F_2(x,Q^2) for momentum transfers squared Q^2 >= 1.5 GeV^2 and Bjorken x >= 3.5…