Ups and downs

We applaud our colleagues at the Deutsches Electronen-Synchrotron (DESY) in Hamburg, Germany, for their successful operation of the HERMES detector (A. Watson, Research News, 21 Mar., p. 1742), which reconfirmed results on the spin structure of the neutron that had previously been measured at the European center for particle physics (CERN) and the Stanford Linear Accelerator Center (SLAC). The experiments described by Watson are of a kind called “inclusive,” where the inelastically scattered lepton (mu-meson at CERN, electron at SLAC, positron at DESY) is detected and the nucleon final state system is not analyzed. This is what has been done at CERN and SLAC for more than a decade in a wider kinematic range than is accessible in HERMES. The precision of the most recent SLAC data is far better than has been achieved at HERMES.