1999/08/30 by W. Schäfer, Wolfgang Schäfer, Schäfer, W. +2
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.48550/arxiv.hep-ph/9908503
8 pages, 5 eps-figures. Talk given at the 6th INT / JLAB Workshop on Exclusive and Semiexclusive Processes at High Momentum Transfer, Newport News, VA, 19-23 May 1999
arxiv created 1999/08/30 · openalex publication_date 1999/08/30 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We revisit the evaluation of the pionic mechanism of the u-d-asymmetry in the proton structure function. Our analysis is based on the unitarity relation between contributions of different mechanisms to the inclusive particle production and the total photoabsorption cross-section (i.e. the proton structure function). We reanalyze the role of isovector reggeons in inclusive production of nucleons and Delta isobars in hadronic reactions. A rather large contribution of reggeon-exchange induced production of Delta isobars is found. This leaves much less room for the pion-exchange induced mechanism of Δ production and provides a constraint on the πN Δ form factor. The production of leading pions in proton-proton collisions puts additional constraints on the πNN vertex form factors. All these constraints are used then to estimate the pion content of the nucleon and allow to calculate parameter-free the x-dependence of d - u. We discuss the violation of the Gottfried Sum Rule and d- u asymmetry and compare to the one obtained from the E866 experiment at Fermilab.