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We use the meson cloud model to calculate $\bar{d}(x) - \bar{u}(x)$ and $ \bar{d}(x)/\bar{u}(x)$ in the proton. We show that a modification of the symmetric, perturbative part of the light quark sea provides better agreement with the ratio…

High Energy Physics - Phenomenology · Physics 2008-11-26 Mary Alberg , Ernest M. Henley

We explore the meson cloud contribution to nucleon electromagnetic form factors in dispersion relation approach. In our calculations, experimental data on transition amplitudes for pion-nucleon scatterings are taken directly as inputs, with…

High Energy Physics - Phenomenology · Physics 2024-09-27 Ek-ong Atthaphan , Attaphon Kaewsnod , Kai Xu , Moh Moh Aung , Warintorn Sreethawong , Ayut Limphirat , Yupeng Yan

We take into account the sigma meson cloud effect in the meson cloud model to calculate the distributions of light flavor sea quarks in the proton. Our calculation gives a better description of the data for $\bar{d}(x)/\bar{u}(x)$. We also…

High Energy Physics - Phenomenology · Physics 2009-11-10 Feng Huang , Rong-Guang Xu , Bo-Qiang Ma

The parton content of the nucleon is explored within a meson-cloud model developed to derive light-cone wave functions for the physical nucleon. The model is here applied to study electromagnetic form factors, distribution amplitudes and…

High Energy Physics - Phenomenology · Physics 2010-01-26 S. Boffi , B. Pasquini

The meson-cloud model of the nucleon consisting of a system of three valence quarks surrounded by a meson cloud is applied to study the electroweak structure of the proton and neutron. The electroweak nucleon form factors are calculated…

High Energy Physics - Phenomenology · Physics 2015-05-13 B. Pasquini , S. Boffi

The meson-cloud model of the nucleon consisting of a system of three valence quarks surrounded by a meson cloud is applied to study the electroweak structure of the proton and neutron. Light-cone wavefunctions are derived for the dressed…

High Energy Physics - Phenomenology · Physics 2008-11-26 B. Pasquini , S. Boffi

The strange and antistrange quark distributions of the nucleon are less constrained by experimental data than the non-strange quark sea. The combination of light quark sea distributions, $\Delta(x)=\dbar(x)+\ubar(x)-s(x)-\sbar(x)$,…

High Energy Physics - Phenomenology · Physics 2010-08-26 H. Chen , F. -G. Cao , A. I. Signal

We have applied the Meson Cloud Model to calculate inclusive momentum spectra of pions and kaons produced in high energy proton-proton and proton-nucleus collisions. For the first time these data are used to constrain the cloud cut-off…

High Energy Physics - Phenomenology · Physics 2009-10-31 F. Carvalho , F. O. Durães , F. S. Navarra , M. Nielsen

Flavor asymmetry is investigated in polarized light-antiquark distributions by a meson-cloud model. In particular, rho meson contributions to Delta u-bar - Delta d-bar are calculated. We point out that the g_2 part of rho contributes to the…

High Energy Physics - Phenomenology · Physics 2009-11-07 S. Kumano , M. Miyama

We apply the Meson Cloud Model to the calculation of nonsinglet parton distributions in the nucleon sea, including the octet and the decuplet cloud baryon contributions. We give special attention to the differences between nonstrange and…

High Energy Physics - Phenomenology · Physics 2014-11-17 F. Carvalho , F. O. Durães , F. S. Navarra , M. Nielsen , F. M. Steffens

We study the possible contribution of the nucleon's virtual meson cloud to the sea quark distribution as observed in deep inelastic lepton scattering. We adjust the meson-nucleon cut-offs to the large-x tails of the antiquark distributions,…

High Energy Physics - Phenomenology · Physics 2007-05-23 W. Koepf , L. L. Frankfurt , M. Strikman

We examine the space-time properties of the distribution (dbar - ubar) and dbar/ubar in the proton. The difference of the antiquark distributions shows the expected peak at the approximate pion Compton wavelength and is supportative of the…

High Energy Physics - Phenomenology · Physics 2014-11-17 Ernest M. Henley , Thorsten Renk , Wolfram Weise

We evaluate the two--pion contribution to the nucleon electromagnetic form factors by use of dispersion analysis and chiral perturbation theory. After subtraction of the rho--meson component, we calculate the distributions of charge and…

High Energy Physics - Phenomenology · Physics 2009-11-10 H. -W. Hammer , D. Drechsel , Ulf-G. Meißner

We use the meson cloud model, including the kaon and the $K^*$ contributions, to estimate the electric and magnetic strange form factors of the nucleon. We compare our results with the recent measurements of the strange quark contribution…

Nuclear Theory · Physics 2009-11-11 Fabiana Carvalho , Fernando S. Navarra , Marina Nielsen

The resonance model is used to analyze the omega- and phi-meson angular distributions in proton-proton collisions at sqrt{s} = 2.83 and 2.98 GeV. The assumption of dominant contributions from N^*(1720)3/2+ and N^*(1900)3/2+ resonances which…

Nuclear Theory · Physics 2009-11-10 Amand Faessler , C. Fuchs , M. I. Krivoruchenko , B. V. Martemyanov

We present a complete set of formulas for longitudinal momentum distribution functions (splitting functions) of mesons in the nucleon. It can be applied in the framework of convolution formalism to the deep-inelastic structure functions…

High Energy Physics - Phenomenology · Physics 2014-11-17 H. Holtmann , A. Szczurek , J. Speth

I review progress in calculating strange quark and antiquark distributions of the nucleon using the meson cloud model. This progress parallels that of the meson cloud model, which is now a useful theoretical basis for understanding symmetry…

Nuclear Theory · Physics 2015-05-18 A. I. Signal

We calculate the spin dependent structure functions g1(x) and g2(x) of the proton and neutron. Our calculation uses the meson cloud model of nucleon structure and includes the effects of kinematic terms which mix transverse and longitudinal…

High Energy Physics - Phenomenology · Physics 2015-06-25 A. I. Signal

Dispersion relations provide a powerful tool to analyse the electromagnetic form factors of the nucleon for all momentum transfers. Constraints from meson-nucleon scattering data, unitarity, and perturbative QCD can be included in a…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. A. Belushkin , H. -W. Hammer , U. -G. Meißner

Studying the possible breaking of various parton model symmetries by the parton distribution functions of the nucleon can provide important information for the non-perturbative structure of hadrons and the strong interaction. We review…

High Energy Physics - Phenomenology · Physics 2015-06-03 Fu-Guang Cao
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