Pentaquarks with a hidden flavour and the hypothesis of the intrinsic charm of the proton

Abstract

Using the experimental data on pentaquarks with a hidden charm, new upper limits on the intrinsic charm in the proton are obtained, possible shapes of heavy quark distributions inside the proton are discussed.

Comments: 9 pages, 2 figures new version: several references added, text improved according referee's recommendation, quark distribution for pentaquark with hidden strangeness obtained, accepted by Physics of Atomic Nuclei