1208.5427 (M. Stolarski)

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    [PDF]

M. Stolarski

In this paper the author discusses the article by the HERMES Collaboration, Phys. Lett. B 666, 446 [arXiv:0803.2993], where several important results concerning strange quark properties in the nucleon were presented. The strange sea distribution was found to be very different from the non-strange in the Bjorken x scaling variable. In addition, the magnitude of these two distributions at low x is similar, contrary to most of the available Parton Distribution Function sets. The strange quark helicity distribution was also extracted combining inclusive and semi-inclusive kaon asymmetries. The result of the first moment of the strange quarks helicity distribution in the measured range is slightly positive, while a rather significant negative value is expected from the world polarised inclusive Deep Inelastic Scattering measurements. The author shows that a certain combination of fragmentation functions extracted from the preliminary HERMES kaon multiplicities presents a very strong Q2 dependence. Such a strong dependence is not expected from the DGLAP evolution of the fragmentation functions. If a similar dependence was present in the data used in the analyses of the discussed article, their conclusion might have to be altered.

View original: http://arxiv.org/abs/1208.5427