Light-Cone Wavefunction Representations of Sivers and Boer-Mulders Distribution Functions

We find the light-cone wavefunction representations of the Sivers and Boer-Mulders distribution functions. A necessary condition for the existence of these representations is that the light-cone wavefunctions have complex phases. We induce the complex phases by incorporating the final-state interactions into the light-cone wavefunctions. For the scalar and axial-vector diquark models for nucleon, we calculate explicitly the Sivers and Boer-Mulders distribution functions from the light-cone wavefunction representations. We obtain the results that the Sivers distribution function has the opposite signs with the factor 3 difference in magnitude for the two models, whereas the Boer-Mulders distribution function has the same sign and magnitude. We can understand these results from the properties of the light-cone wavefunction representations of the Sivers and Boer-Mulders distribution functions.Comment: 11 pages, 4 figure

Spin Correlations of Lambda anti-Lambda Pairs as a Probe of Quark-Antiquark Pair Production

The polarizations of Lambda and anti-Lambda are thought to retain memories of the spins of their parent s quarks and antiquarks, and are readily measurable via the angular distributions of their daughter protons and antiprotons. Correlations between the spins of Lambda and anti-Lambda produced at low relative momenta may therefore be used to probe the spin states of s anti-s pairs produced during hadronization. We consider the possibilities that they are produced in a 3P_0 state, as might result from fluctuations in the magnitude of , a 1S_0 state, as might result from chiral fluctuations, or a 3S_1 or other spin state, as might result from production by a quark-antiquark or gluon pair. We provide templates for the p anti-p angular correlations that would be expected in each of these cases, and discuss how they might be used to distinguish s anti-s production mechanisms in pp and heavy-ion collisions.Comment: 12 pages, 3 figure

Higher Fock sectors in Wick-Cutkosky model

In the Wick-Cutkosky model we analyze nonperturbatively, in light-front dynamics, the contributions of two-body and higher Fock sectors to the total norm and electromagnetic form factor. It turns out that two- and three-body sectors always dominate. For maximal value of coupling constant $\alpha=2\pi$, corresponding to zero bound state mass M=0, they contribute 90% to the norm. With decrease of $\alpha$ the two-body contribution increases up to 100%. The form factor asymptotic is always determined by two-body sector.Comment: 4 pages, 2 figures, to appear in the proceedings of Light Cone 2004, Amsterdam, August 16-20, 200

A Method of Experimentally Probing Transeverse Momentum Dependent Distributions

We calculate the double spin asymmetry A_LL(x, y, z, P_hT) of pi^0 production with the spectator model and the model based on the factorization ansatz. We also calculate the double spin asymmetry for the integration over the range of (x,y,z) for the setups of the experiments of COMPASS, HERMES, and JLab. We find that the results are characteristically dependent on the model used. Therefore, we suggest that the measurements of the double spin asymmetry provides a method of experimentally probing the transeverse momentum dependent distributions.Comment: 10 pages, 31 figure