Related papers: Investigating Partons' Transverse Spin with Deep I…
The relevance of intrinsic (or primordial) transverse momentum of partons in the inclusive production of particles at high energy and moderately large p_T has been known for a long time, beginning with Drell-Yan and diphoton processes, and…
It has recently been suggested that collisions of transversely polarized protons and antiprotons at the GSI could be used to determine the nucleon's transversity densities from measurements of the double-spin asymmetry for the Drell-Yan…
We compute the one-loop contributions to spin-averaged generalized parton distributions (GPDs) in the proton from pseudoscalar mesons with intermediate octet and decuplet baryon states at nonzero skewness. Our framework is based on nonlocal…
Large-distance effects, which lead to the spin-flip part of the hadron -pomeron coupling in QCD -models, are discussed. We study spin asymmetries in exclusive reactions and in diffractive $Q \bar Q$ and vector meson production which are…
The investigation of transverse spin and transverse momentum effects in deep inelastic scattering is one of the key physics programs of the COMPASS collaboration. In the years 2002-2004 COMPASS took data scattering 160 GeV muons on a…
The helicity-dependent strange quark distribution in the proton, $\Delta s$, is calculated in a nonlocal chiral SU(3) effective field theory. The hadronic proton to meson plus octet or decuplet baryon splitting functions are derived at the…
We present the first extraction of the transversity distribution based on the global analysis of pion-pair production in deep-inelastic scattering and in proton-proton collisions with one transversely polarized proton. The extraction relies…
The cross section of the exclusive $\pi^0$ and $\eta$ electroproduction reaction $ep\to e^\prime p^\prime \pi^0/\eta$ was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections…
The chiral-odd transversity generalized parton distributions (GPDs) of the nucleon can be accessed experimentally through the exclusive photoproduction process gamma + N -> pi + rho + N', in the kinematics where the meson pair has a large…
Transversity generalized parton distributions (GPDs) appear as scalar functions in the decomposition of off-forward quark-quark and gluon-gluon correlators with a parton helicity flip. For a spin 1 hadron, we find 9 transversity GPDs for…
We present an improved determination of the strange quark and anti-quark parton distribution functions of the proton by means of a global QCD analysis that takes into account a comprehensive set of strangeness-sensitive measurements:…
We show within proton hot spot picture that the exclusive vector meson production in electron-proton deeply inelastic scattering is sensitive to the individual width of the constituent quarks of the proton. For comparison, we calculate the…
Exclusive quarkonium photo- and electro-production off the nucleon is studied in the framework of generalized parton distributions (GPDs). The short distance part of the process is treated at leading order in perturbative Quantum…
We analyze one-particle inclusive DIS in the case when a spin-1 hadron (such as a vector meson) is observed in the final state. We consider only leading order contributions in 1/Q, but we include transverse momentum of partons. Several new…
The proton spin puzzle has inspired a vast programme of experiments and theoretical work challenging our understanding of QCD and its role in the structure of hadrons.The proton's internal spin structure is connected to chiral symmetry and,…
We discuss exclusive elastic double diffractive axial-vector $\chi_c(1^+)$ and tensor $\chi_c(2^+)$ mesons production for different meson polarisations in proton-(anti)proton collisions at the Tevatron energy. The amplitude for the process…
Exclusive electro-weak processes have peculiar features which make them complementary to usually discussed deeply virtual electroproduction processes such as deep virtual Compton scattering or meson production (and the corresponding crossed…
Selected recent results from the H1 and ZEUS experiments are reviewed, illustrating some of the many facets of ``meson physics'' at the HERA ep collider. The results cover exclusive elastic and proton-dissociative diffractive vector meson…
We analyze light meson electroproduction in the intermediate energy range where the quark contributions are essential. Our calculations are carried out on the basis of the handbag approach. We study cross sections and spin asymmetries for…
We analyze the light meson leptoproduction within the handbag approach. We show that effects determined by the transversity Generalized Parton Distributions (GPDs), $H_T$ and $\bar E_T$ are essential in the description of pseudoscalar and…