40 research outputs found
Determination of flavor asymmetry for by the Drell-Yan process
Flavor asymmetries for the valence and sea quarks of the can
be obtained from Drell-Yan experiments using charged hyperon beams on proton
and deuteron targets. A large, measurable difference in sea quark asymmetries
is predicted between SU(3) and pseudoscalar meson models. The latter predict
that in , , whereas the former predict
. Estimates of valence quark asymmetries based on
quark models also show large deviations from SU(3) predictions, which should be
measurable.Comment: 15 pages, latex. Figures available from [email protected].
To be published in Phys. Lett.
Omega Meson Cloud and the Proton's Light Anti-Quark Distribution
We use the meson cloud model of the nucleon to calculate distribution
functions for and in the proton.
Including the effect of the omega meson cloud, with a coupling constant
, allows a reasonably good description of the data.Comment: 6 pages, 2 figures, LaTe
The Quark Distributions in the \Sigma^+ Hyperon
We use the meson cloud model and the Sullivan mechanism to estimate the sea
flavor asymmetry in the \Sigma^+ baryon and calculate the distribution
functions of both sea and valence quarks. We find large deviations from SU(3).Comment: 13 pages, 11 figure
Taming the Pion Cloud of the Nucleon
We present a light-front determination of the pionic contribution to the
nucleon self-energy, , to second-order in pion-baryon coupling
constants that allows the pion-nucleon vertex function to be treated in a
model-independent manner constrained by experiment. The pion mass
dependence of is consistent with chiral perturbation theory
results for small values of and is also linearly dependent on for
larger values, in accord with the results of lattice QCD calculations. The
derivative of with respect to yields the dominant
contribution to the pion content, which is consistent with the
difference observed experimentally in the violation of the
Gottfried sum rule.Comment: 11 pages, 3 figure
Light quark distributions in the proton sea
We use the meson cloud model to calculate and in the proton. We show that a modification of the
symmetric, perturbative part of the light quark sea provides better agreement
with the ratio $ \bar{d}(x)/\bar{u}(x).Comment: 4 pages, 2 figures, LaTeX. Talk presented at PANIC 9