Comments on: "Measurement of Parton Distributions of Strange Quarks in the Nucleon from Charged-Kaon Production in Deep-Inelastic Scattering on the Deuteron" by the HERMES Collaboration

Abstract

In this paper a discussion is made of the article by the HERMES Collaboration, Phys.Lett. B666,446, where several important results concerning strange quark properties in the nucleon were presented. By analysing the sum of K+- multiplicities it was found that the strange sea distribution is very different from the non-strange one as a function of the Bjorken x scaling variable. In addition, the magnitude of these two distributions at low x is similar, contrary to the behaviour in most of the available parton distribution function sets. It is shown that the obtained distribution of the unpolarised strange quark influences our understanding of the "strange quark polarisation puzzle". It is argued that the sole analysis of the sum of K+- multiplicities, as done in the HERMES paper, might not be sufficient to draw solid conclusions about the strange sector. A simultaneous analysis of the difference of K+- multiplicities should be done in general. To show that this is not simply an academic case, the author presents an analysis based on the HERMES preliminary data, where the sum and the difference of the K+- multiplicities are considered.