Meson cloud and SU(3) symmetry breaking in parton distributions

Carvalho, F.; Durães, F. O.; Navarra, F. S.; Nielsen, M.; Steffens, Fernanda

doi:10.1007/s100520000512

“…[58] and the E866 d/u ratio and d − u difference relatively well [69]. However, if antisymmetrization of the quark wavefunctions is included, the conclusion could change dramatically [75].…”

Section: Effects Of Pauli Blockingmentioning

confidence: 97%

Physics of the Nucleon Sea Quark Distributions

Vogt¹

2000

Progress in Particle and Nuclear Physics

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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 or heavy quark sea distributions are predicted in the improved parton model. However, recent experiments have called these naive expectations into question. A violation of the Gottfried sum rule has been measured in several experiments, suggesting that u < d in the proton. Additionally, other measurements, while not definitive, show that there may be an asymmetry in the strange and anti-strange quark sea distributions. These effects may require nonperturbative explanations. In this review we first discuss the perturbative aspects of the sea quark distributions. We then describe the experiments that could point to nonperturbative contributions to the nucleon sea. Current phenomenological models that could explain some of these effects are reviewed.

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“…Moreover, it is important to emphasize that in the case of the more familiar exponential (3), monopole (6) and dipole (7) forms factors, the cut-off parameters have been determined by fitting low energy data on nucleon and nuclear reactions and also data on deep inelastic scattering and structure functions [21]. In Ref.…”

Section: Exclusive Processes Associated With Leading Neutron Prodmentioning

confidence: 99%

Exclusive processes with a leading neutron inepcollisions

Gonçalves

¹

,

Navarra

²

,

Spiering

³

2016

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In this paper we extend the color dipole formalism to the study of exclusive processes associated with a leading neutron in ep collisions at high energies. The exclusive ρ, φ and J/Ψ production, as well as the Deeply Virtual Compton Scattering, are analysed assuming a diffractive interaction between the color dipole and the pion emitted by the incident proton. We compare our predictions with the HERA data on ρ production and estimate the magnitude of the absorption corrections. We show that the color dipole formalism is able to describe the current data. Finally, we present our estimate for the exclusive cross sections which can be studied at HERA and in future electron-proton colliders.

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“…11, may successfully explain the difference d − u, they usually have trouble reproducing the ratio d/u. An approach that has had relative success in obtaining agreement with both the difference and the ratio is the inclusion of a perturbative component in the meson cloud [68,69]. The analysis of Ref.…”

Section: Meson Cloud Modelsmentioning

confidence: 99%

Physic of the nucleon sea quark distributions

Vogt¹

2000

Progress in Particle and Nuclear Physics

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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 or heavy quark sea distributions are predicted in the improved parton model. However, recent experiments have called these naive expectations into question. A violation of the Gottfried sum rule has been measured in several experiments, suggesting that u < d in the proton. Additionally, other measurements, while not definitive, show that there may be an asymmetry in the strange and anti-strange quark sea distributions. These effects may require nonperturbative explanations. In this review we first discuss the perturbative aspects of the sea quark distributions. We then describe the experiments that could point to nonperturbative contributions to the nucleon sea. Current phenomenological models that could explain some of these effects are reviewed.

show abstract

Meson cloud and SU(3) symmetry breaking in parton distributions

Cited by 22 publications

References 19 publications

Physics of the Nucleon Sea Quark Distributions

Physics of the Nucleon Sea Quark Distributions

Exclusive processes with a leading neutron inepcollisions

Physic of the nucleon sea quark distributions

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