We explore the relationship between exclusive and inclusive electromagnetic scattering from the pion, focusing on the transition region at intermediate Q2. Combining Drell-Yan data on the leading twist quark distribution in the pion with a model for the resonance region at large x, we calculate QCD moments of the pion structure function over a range of Q2, and quantify the role of higher twist ...

We present a phenomenological approach to the description of single transverse spin asymmetries (STSA) in inclusive hadron production. It generalizes the pQCD formalism for high energies and large pT inclusive hadron production processes, AB → C X, by incorporating quark intrinsic motion in the spin dependent quark distribution and fragmentation functions. We concentrate here on spin and k⊥ eff...

We calculate the Drell-Yan cross section, resolving the full kinematics of the lepton pair, at high transverse momentum for hadron nucleus collisions. We use the general framework of Luo, Qiu and Sterman to calculate double scattering contributions that are of twist-4 and demonstrate their nuclear enhancement. By comparing single and double scattering at RHIC energies we find that double scatte...

These lectures give a pedagogical introduction to real and virtual Compton scattering at low energies. We will first discuss real Compton scattering off a point particle as well as a composite system in the framework of nonrela-tivistic quantum mechanics. The concept of electromagnetic polarizabilities is introduced. We then address a description of the Compton-scattering ten-sor within quantum...

An outline is explained for hadron-physics projects at J-PARC, which is considered to be one of the flagship facilities in hadron physics from 2008. The facility provides an intensity frontier with 50 GeV proton beam for nuclear and particle physics. It could cover a wide range of hadron physics from strongly interacting many-body systems with an extended hadronic degree of freedom, strangeness...

We propose to study quark-hadron duality in meson electroproduction. While duality between inclusive electron-hadron scattering in the resonance and deep inelastic regimes (Bloom-Gilman or quark-baryon duality) is well established, the existence of a similar duality in meson electroproduction has not yet been tested. In the inclusive case, duality implies that single-quark scattering governs th...

We perform a comprehensive new Monte Carlo analysis of high-energy lepton-lepton, lepton-hadron and hadron-hadron scattering data to simultaneously determine parton distribution functions (PDFs) in the proton hadron fragmentation (FFs). The includes all available semi-inclusive deep-inelastic single-inclusive ${e}^{+}{e}^{\ensuremath{-}}$ annihilation for pions, kaons unidentified charged hadro...

It is shown that the azimuthal dependence of the distribution of hadrons in a quark jet is a probe of the transverse spin of the quark initiating the jet. This results in a new spin-dependent fragmentation function that acts at the twist-2 level. One example of a process where it contributes is semi-inclusive deeply inelastic scattering with a transversely polarized nucleon target but with an u...

The light-front representation of quantum chromodynamics provides a frame-independent, quantum-mechanical representation of hadrons at the amplitude level, capable of encoding their multi-quark, hidden-color and gluon momentum, helicity, and flavor correlations in the form of universal process-independent hadron wavefunctions. The universality and frame-independence of the LCWF’s thus allow a p...

QCD at the classical level possesses scale invariance which is broken by quantum effects. This “dimensional transmutation” phenomenon can be mathematically described by formulating classical gluodynamics in a curved, conformally flat, space–time with non–vanishing cosmological constant. We study QCD high–energy scattering in this theory. We find that the properties of the scattering amplitude a...