Pion cloud and sea quark flavor asymmetry in the impact parameter representation
نویسندگان
چکیده
We study large–distance contributions to the nucleon parton densities in the transverse coordinate (impact parameter) representation based on generalized parton distributions (GPDs). Chiral dynamics generates a distinct component of the partonic structure, located at momentum fractions x . Mπ/MN and transverse distances b ∼ 1/Mπ . We analyze the phenomenological “pion cloud” model of the flavor asymmetry d(x)−u(x) and quantify what fraction of the calculated asymmetry results from the universal large–distance region. Our findings indicate that a two–component picture of the nucleon’s partonic structure, with a “core” antiquark distribution at b < bcore ≈ 0.55fm which vanishes at x → 0 and the universal large–distance pion cloud, could naturally account for the x–dependence of the measured asymmetry.
منابع مشابه
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