Study of the isospin symmetry breaking in the light quark sea of the nucleon from the Drell-Yan process

Baldit, A.; Barrière, C.; Castor, J.; Chambon, T.; Devaux, A.; Espagnon, B.; Fargeix, J.; Force, P.; Landaud, G.; Saturnini, P.; Vazeille, F.; Sonderegger, P.; Abreu, M.C.; Bordalo, P.; Ferreira, R.; Lourenço, C.; Ramos, S.; Silva, S.; Varela, J.; Gerschel, C.; Jouan, D.; Tarrago, X.; Chaurand, B.; Kluberg, L.; Romana, A.; Gorodetzky, P.; Lazic, D.; Mazini, R.; Racca, C.; Alessandro, B.; Chiavassa, E.; Dellacasa, G.; Gallio, M.; Giubellino, P.; Guaita, P.; Marzari‐Chiesa, A.; Masera, M.; Monteno, M.; Musso, A.; Ramello, L.; Riccati, L.; Scomparin, E.; Vercellin, E.; Bedjidian, M.; Contardo, D.; Descroix, E.; Drapier, O.; Grossiord, J.‐Y.; Guichard, A.; Haroutunian, R.; Malek, F.; Mandry, R.; Pizzi, J.R.

doi:10.1016/0370-2693(94)90884-2

Cited by 342 publications

(277 citation statements)

References 12 publications

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“…We will find, surprisingly, that our simplified calculation gives the correct light flavor sea-quark asymmetry, i.e.,ū =d, which has been observed in experiments [5][6][7][8][9][10]. This implies that the number of valence quarks controls the statistical property of the proton.…”

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confidence: 81%

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Detailed balance and sea-quark flavor asymmetry of proton

Zhang

2001

Physics Letters B

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In this study, the proton is taken as an ensemble of quark-gluon Fock states.Using the principle of detailed balance, the probabilities of finding every Fock states of the proton are obtained without any parameter. A new origin of the light flavor sea quark asymmetry, i.e.,ū =d, is given as a pure statistical effect. It is found thatd −ū ≈ 0.124, which is in surprisingly agreement with the experimental observation.

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confidence: 81%

“…It is very interesting that only from the pure statistical consideration, we get an asymmetry between the light flavor u and d sea quarks, i.e.,ū =d, which has been observed in deep inelastic scattering and Drell-Yan experiments [5][6][7][8][9][10].…”

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confidence: 99%

Detailed balance and sea-quark flavor asymmetry of proton

Zhang

2001

Physics Letters B

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“…While the generation of ss pairs through perturbative gluon radiation typically produces symmetric s ands distributions (at least up to two loop corrections [16]), any significant difference between the momentum dependence of the s ands parton distribution functions (PDFs) would be a clear signal of nonperturbative effects. In fact, insights from chiral symmetry breaking in the nonstrange sector led to the prediction [17] of an excess ofd antiquarks over u in the proton, which was spectacularly confirmed in DIS [18,19] and Drell-Yan [20,21] experiments more than a decade later. A similar mechanism, which can be intuitively realized in the form of a pseudoscalar meson cloud surrounding a valence-quark nucleon core, was subsequently used [22] to demonstrate the natural emergence of a nonzero s −s asymmetry from the breaking of the chiral SU(3) symmetry of QCD.…”

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confidence: 93%

Strange-quark asymmetry in the proton in chiral effective theory

Wang

Melnitchouk

et al. 2016

Phys. Rev. D

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We perform a comprehensive analysis of the strange-antistrange parton distribution function (PDF) asymmetry in the proton in the framework of chiral effective theory, including the full set of lowest order kaon loop diagrams with off-shell and contact interactions, in addition to the usual on-shell contributions previously discussed in the literature. We identify the presence of δ-function contributions to thes PDF at x = 0, with a corresponding valence-like component of the s-quark PDF at larger x, which allows greater flexibility for the shape of s −s. Expanding the moments of the PDFs in terms of the pseudoscalar kaon mass, we compute the leading nonanalytic behavior of the number and momentum integrals of the s ands distributions, consistent with the chiral symmetry of QCD. We discuss the implications of our results for the understanding of the NuTeV anomaly and for the phenomenology of strange quark PDFs in global QCD analysis.

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“…Recent measurements [1][2][3][4] have shown a large asymmetry in the distributions of up and down antiquarks (ū andd) in the nucleon. While no known symmetry requiresū to equald, a larged/ū asymmetry was not anticipated.…”

Section: Introductionmentioning

confidence: 99%

Improved measurement of thed¯/ūasymmetry in the nucleon sea

et al. 2001

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Measurements of the ratio of Drell-Yan yields from an 800 GeV/c proton beam incident on liquid hydrogen and deuterium targets are reported. Approximately 360,000 Drell-Yan muon pairs remained after all cuts on the data. ¿From these data, the ratio of anti-down (d) to anti-up (ū) quark distributions in the proton sea is determined over a wide range in Bjorken-x. These results confirm previous measurements by E866 and extend them to lower x. From these data, (d −ū) and (d −ū)dx are evaluated for 0.015 < x < 0.35. These results are compared with parameterizations of various parton distribution functions, models and experimental results from NA51, NMC and HERMES. 13.85.Qk; 14.20.Dh; 24.85.+p; 14.65.Bt

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Study of the isospin symmetry breaking in the light quark sea of the nucleon from the Drell-Yan process

Cited by 342 publications

References 12 publications

Detailed balance and sea-quark flavor asymmetry of proton

Detailed balance and sea-quark flavor asymmetry of proton

Strange-quark asymmetry in the proton in chiral effective theory

Improved measurement of thed¯/ūasymmetry in the nucleon sea

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