Perturbative QCD relates the single transverse-spin asymmetries (SSAs) for hard processes at large transverse-momentum of produced particle to partonic matrix elements that describe interference between scattering from a coherent quark-gluon pair and from a single quark, generated through twist-3 quark-gluon correlations inside a hadron. When the coherent gluon is soft at the gluonic poles, its...

We compute the scattering lengths of charmed mesons and charmonia scattering with light hadrons in full QCD. We use Fermilab formulation for the charm quark and domain-wall fermions for the light quarks and staggered sea quarks. Four different light-quark masses are used to extrapolate to the physical point. The charmed baryon spectrum is also presented.

We show how quark-hadron duality can emerge for valence spin averaged structure functions, and for the non-forward distributions of Deeply Virtual Compton Scattering. Novel factorisations of the non-forward amplitudes are proposed. Some implications for large angle scattering and deviations from the quark counting rules are illustrated. PACS numbers: 12.39.-x, 12.40.Nn, 13.60.Hb

s-channel helicity conservation (SHC) for Pomeron exchanging amplitude was discovered empirically for rP----"PoP reaction, 1l and was suggested to hold also in the case of nN elastic scattering_"> Later analysis on nN scattering amplitudes,3> however, showed that the ratio, IF1_1f(IF~+i.J-T/s0 ), which may be considered as a barometer of the violation of SHC for I, =0 exchanging amplitudes, was...

We consider elastic quark-quark scattering at high energy and fixed transferred momentum. Performing factorization of soft gluon exchanges into Wilson lines vacuum expectation values and studying their properties, we find that the asymptotics of the scattering amplitude is controlled by the renormalization properties of the so called cross singularities of Wilson loops. Using this fact, we eval...

The parton–parton scattering amplitude, at high squared energies s in the center of mass and small squared transferred momentum t (that is s → ∞ and |t| ≪ s, let us say |t| ≤ 1 GeV), can be described by the expectation value of two infinite Wilson lines, running along the classical trajectories of the two colliding particles [1–4]. Let us consider, for example, the case of the quark–quark scatt...

We calculate the doublet and quartet neutron-deuteron scattering lengths using a nonlocal nucleon-nucleon interaction fully derived from quark-quark interactions. We use as input the NN S0 and S1D1 partial waves. Our result for the quartet scattering length agrees well with the experimental value while the result for the doublet scattering length does not. However, if we take the result for the...

According to QED in the hard charged longitudinally polarized lepton–unpolarized quark scattering l + q → l + q lepton transfers its polarization to final quark. Within the simple parton model description of SIDIS the hadron production in the current fragmentation region is described by independent fragmentation of scattered quark. Then the (anti)quark polarization can be transferred to produce...

We use an s-channel picture of hard hadronic collisions to investigate the parton distribution function for quarks at small momentum fraction x, which corresponds to very high energy scattering. We study the renormalized quark distribution at one loop in this approach. In the high-energy picture, the quark distribution function is expressed in terms of a Wilson-line correlator that represents t...