相关论文: Polarized strangeness in the nucleon
The OZI rule have been tested in a number of experiments in a wide interval of energies. It was found that the rule is fulfilled well, within few percent of accuracy. The results of experiments with stopped antiprotons at LEAR (CERN), where…
We have previously interpreted the various large apparent violations of the naive Okubo-Zweig-Iizuka (OZI) rule found in many channels in $\bar{p}p$ annihilation at LEAR as evidence for an intrinsic polarized $\bar{s}s$ component of the…
There are several different experimental indications, such as the pion-nucleon sigma term and polarized deep-inelastic scattering, which suggest that the nucleon wave function contains a hidden s bar s component. This is expected in chiral…
Violations of the Okubo-Zweig-Iizuka (OZI) rule in $s\bar s <-> n\bar n = 1/2 (u\bar u + d\bar d)$ mixing and $\phi$ production from nucleon-antinucleon annihilation are reviewed. Possible explanations are examined. We conclude that the…
The nucleon wave function may contain a significant component of ssbar pairs, according to several measurements including the pi-nucleon sigma term, charm production and polarization effects in deep-inelastic scattering. In addition, there…
We investigate the flavour and quark-antiquark structure of the polarized nucleon by calculating the parton distribution functions of the nucleon sea using the meson cloud model. We find that the SU(2) flavor symmetry in the light antiquark…
Extraction of the nucleon's strange form factors from experimental data requires a quantitative understanding of the unavoidable contamination from isospin violation. A number of authors have addressed this issue during the past decade, and…
We review a recent theoretical determination of the strange quark content of the electromagnetic form factors of the nucleon. These are compared with a global analysis of current experimental measurements in parity-violating electron…
Apparent channel-dependent violations of the OZI rule in nucleon-antinucleon annihilation reactions are discussed in the presence of an intrinsic strangeness component in the nucleon. Admixture of strange-antistrange quark pairs in the…
Sea quark distributions in the nucleon have naively been expected to be generated perturbatively by gluon splitting. In this case, there is no reason for the light quark and anti-quark sea distributions to be different. No asymmetries in…
The strange sea of the proton is generally assumed to have quark - antiquark symmetry. However it has been known for some time that non-perturbative processes involving the meson cloud of the proton may break this symmetry. Recently this…
The proton spin problem triggered by the EMC experiment and its present status are closely examined. Recent experimental and theoretical progresses and their implications are reviewed. It is pointed out that the sign of the sea-quark…
The data from the last seven experiments performed on polarized deep--inelastic scattering on proton and neutron (or deuteron) targets have been analyzed in search of a precise determination of the spin fraction carried by the quarks in the…
We study the polarization of the anti-Lambda particle in polarized high energy pp collisions at large transverse momenta. The anti-Lambda polarization is found to be sensitive to the polarization of the anti-strange sea of the nucleon. We…
The strange form factors of the proton are basic to an understanding of proton structure, and are presently the focus of many experiments. Before the strangeness effects can be extracted from data, it is necessary to calculate and remove…
We study the possibility to constrain the hidden strangeness content of the nucleon by means of the polarization observables in phi meson electroproduction. We consider the OZI evading direct knockout mechanism that arises from the…
There are several different experimental indications, such as the strangeness contribution to the magnetic moment of the proton, sigma_{\pi N} term, strange spin polarization, ratio of strange and non strange quark flavor distributions…
Theoretical predictions are given for the strange sea distributions in the nucleon based on the flavor SU(3) chiral quark soliton model, with emphasis upon the asymmetry of quark and antiquark distributions. We find that the quark-antiquark…
The small mass difference $m_n-m_p=1.3 MeV$ between the proton and neutron leads to an excess of $n=\pi^- p$ over $p=\pi^+ n$ fluctuations which can be calculated by using a light-cone meson-baryon fluctuation model of intrinsic…
The strange sea quarks distributions of nucleons obtained by two global analyses based on available structure function data of muon and neutrino deep inelastic scatterings are different from the strange sea quark distribution measured by…