1,400 research outputs found
On the NuTeV anomaly and the asymmetry of the strange sea in the nucleon
Our recent theoretical analysis based on the flavor SU(3) chiral quark
soliton model predicts fairly large particle-antiparticle asymmetry of the
strange sea in the nucleon. We point out that the predicted magnitude of
asymmetry is large enough to solely resolve the so-called NuTeV anomaly on the
fundamental parameter in the standard model.Comment: 9 pages, 1 figure, revised final version to appear in Phys. Rev.
On the new COMPASS measurement of the deuteron spin-dependent structure function
Very recently, a new measurement of the deuteron spin-dependent structure
function was reported by the COMPASS group. A main change from the
old SMC measurement is a considerable improvement of the statistical accuracy
in the low region . We point out that the new COMPASS
data for as well as their QCD fits for and are all remarkably close to our theoretical predictions
given several years ago based on the chiral quark soliton model.Comment: Errors in Fig.4 were corrected. Version accepted for publication in
Physics Letters
Do we expect light flavor sea-quark asymmetry also for the spin-dependent distribution functions of the nucleon?
After taking account of the scale dependence by means of the standard DGLAP
evolution equation, the theoretical predictions of the chiral quark soliton
model for the unpolarized and longitudinally polarized structure functions of
the nucleon are compared with the recent high energy data. The theory is shown
to explain all the qualitative features of the experiments, including the NMC
data for , , the Hermes and NuSea
data for , the EMC and SMC data for ,
and . Among others, flavor asymmetry of the longitudinally
polarized sea-quark distributions is a remarkable prediction of this model,
i.e., it predicts that with a sizable negative coefficient
(and ) in qualitative consistency with the recent
semi-phenomenological analysis by Morii and Yamanishi.Comment: 14pages, including 5 eps_figures with epsbox.sty, late
The nonperturbative origin of delta-function singularity in the chirally-odd twist-3 distribution function e(x)
We analytically prove that the existence of the delta-function singularity in
the chirally-odd twist-3 distribution of the nucleon is inseparably
connected with the nonvanishing quark condensate as a signal of the spontaneous
chiral symmetry breaking of the QCD vacuum. This singularity in , which
would be observed as a sizable violation of the 1st moment sum rule, is then
interpreted as giving a very rare case that the nontrivial vacuum structure of
QCD manifests in an observable of a localized QCD excitation, i.e. the nucleon.Comment: 9 pages, 1 eps-figur
On the D-term of the nucleon generalized parton distributions
It is known that some of the deeply-virtual-Compton-scattering observables,
for instance, the beam-charge asymmetry in the hard electroproduction of real
photons on the nucleon, are extremely sensitive to the magnitude of D-term
appearing in the parameterization of the generalized parton distributions. We
report a theoretical analysis of both the isoscalar and isovector parts of the
nucleon D-term within the framework of the chiral quark soliton model, without
recourse to the derivative expansion type approximation used in previous works.Comment: 10 pages, 2 eps-figures, small improvements, version to appear in
Phys. Lett.
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