946 research outputs found
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 ,
corresponding to zero bound state mass M=0, they contribute 90% to the norm.
With decrease of 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
- …