Position space interpretation for generalized parton distributions

For an unpolarized target, the generalized parton distribution $H_q(x,0,t)$ is related to the distribution of partons in impact parameter space. The transverse distortion of this distribution for a transversely polarized target is described by $E_q(x,0,t)$.Comment: 6 pages, espcrc1.sty, invited talk, QCDN'02, Ferrara, April 200

Light Front Ensemble Projector Mont Carlo

A new method to perform numerical simulations of light-front Hamiltonians formulated on transverse lattices is introduced. The method is based on a DLCQ formulation for the (continuous) longitudinal directions. The hopping term in the transverse direction introduces couplings between fields defined on neighboring $1+1$-dimensional sheets. Within each sheet, the light-cone imaginary time evolution operator is calculated numerically with high precision using DLCQ. The coupling between neighboring sheets is taken into account using an initial value random walk algorithm based on the ensemble projector Monte Carlo technique and a checkerboard decomposition for the time evolution operator. The structure functions of $\lambda \phi^4$ theory in $2+1$ dimensions are studied as a trial application. The calculations are performed with up to 64 transverse lattice sites. No Tamm-Dancoff truncations are necessary

GPD's and Ssa's

Generalized parton distributions involving transverse polarization are transversely deformed. The deformation of chirally odd GPDs is related to a transversity decomposition of the quark angular momentum. Potential consequences for T-odd single-spin asymmetries (Sivers and Boer-Mulders effects) are discussed.Comment: 8 pages, invited talk presented at "Workshop on Transverse Polarisation Phenomena in Hard Processes" (Transversity 2005), Villa Olmo (Como), 7-10th September 200

Generalized Parton Distributions and Distribution of Partons in the Transverse Plane

I discuss the physical interpretation of GPDs in the limit $\xi=0$, where the $t$ dependence contains information about the distribution of partons in the transverse plane. GPDs thus allow a simultaneous determination of the longitudinal momentum and transverse position of partons in the infinite momentum frame, which also provides a physical interpretation for Ji's angular momentum sum rule.Comment: invited talk at `Workshop on Lepton Scattering, Hadrons and QCD', Adelaide, March 26 - April 6, 2001, 8 pages, sprocl.st

Spin-Orbit Correlations and Single-Spin Asymmetries

Several examples for the role of orbital angular momentum and spin-orbit correlations in hadron structure are discussed.Comment: sign for $h_{1T}^\perp$ correcte