The end of WHAT nucleon-spin crisis?

TL;DR

The paper argues that the so-called nucleon-spin crisis was a misinterpretation of experimental data and that it no longer exists, criticizing recent claims of its resolution.

Contribution

It clarifies the historical misunderstanding of the nucleon-spin crisis and questions the validity of recent proposed solutions based on hadronic photon fluctuations.

Findings

The nucleon-spin crisis was a misinterpretation of deep inelastic scattering data.

Recent claims of resolving the crisis are based on dubious arguments.

The crisis no longer exists as a genuine problem.

Abstract

Povh and Walcher have written a paper entitled "The end of the nucleon-spin crisis" [arXiv:1603.05884]. But there is no such crisis. What appeared to be a spin crisis in the parton model, 28 years ago, was a consequence of a misinterpretation of the results of the famous European Muon Collaboration experiment on polarized deep inelastic scattering. It would thus seem that Povh and Walcher have invoked a somewhat dubious argument based on hadronic fluctuations of the photon in order to resolve a non-existent problem.