Pion cloud and sea quark flavor asymmetry in the impact parameter representation
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 ~< M_pi / M_N and transverse distances b ~ 1/M_pi. We analyze the phenomenological "pion cloud" model of the flavor asymmetry dbar(x) - ubar(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 -- a "core" antiquark distribution at b < b_core ~ 0.55 fm which vanishes at x -> 0, and the universal large-distance pion cloud at b > b_core -- could naturally account for the x-dependence of the measured asymmetry.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-060R23177
- OSTI ID:
- 956120
- Report Number(s):
- JLAB-THY-08-915; DOE/OR/23177-0544; TRN: US1004886
- Resource Relation:
- Conference: Paper compiled for Lightcone 2008: Relativistic Nuclear and Particle Physics
- Country of Publication:
- United States
- Language:
- English
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