Intrinsic light and strange quark--antiquark pairs in the proton and nonperturbative strangeness suppression

Abstract

The CLAS Collaboration recently reported measured ratios of pion and kaon electroproduction cross sections from a proton target and extracted the ratios for light and strange quark--antiquark pairs, $u\bar{u}/d\bar{d}$ and $s\bar{s}/d\bar{d}$. Within an extended chiral constituent quark formalism, we investigate contributions to those ratios from the nonperturbative mechanism due to all possible intrinsic $|uudQ\bar{Q}⟩$ Fock states in the proton; with $Q\bar{Q}\equiv u\bar{u},d\bar{d},s\bar{s},c\bar{c}$. Our results are compared with the CLAS data and findings from other phenomenological approaches, offering insights into the manifestations of the genuine five--quark Fock states in the proton and its relevance to interpreting the experimental data.

Comments: To appear in Phys. Rev. D