Preliminary results are reported from the HERMES experiment at HERA/DESY for the spin asymmetry g 1 =F 1 and the polarised structure function g p 1 of the proton and for an extraction of polarised quark-distributions from a combination of Helium-3 and Hydrogen data The HERMES experiment at DESY uses the HERA 27.5 GeV polarised positron beam in combination with a polarised internal gas target to...

For the first time single–spin asymmetries in semi–inclusive pion production are measured by the Hermes experiment with a transversely polarised hydrogen target. Two different sine–modulations are extracted which can be related to the transversity δq(x) and Sivers f 1T (x) quark distribution functions. The extracted sine–moments still contain small sub–leading twist contributions which can be e...

COMPASS is a running fixed-target experiment at the CERN SPS with a rich physics program focused on nucleon spin structure and on hadron spectroscopy. One of the main goals of the spin program is the measurement of the transverse spin effects in semi-inclusive DIS off transversely polarised nucleons. In the years 2002, 2003 and 2004 data have been taken using a 160 GeV /c naturally polarised µ ...

Three (or four) straightforward experiments would contribute greatly to completing the spectroscopy of baryons and light mesons. In the baryon sector, data are needed on inelastic reactions from a polarised target with π andK beams up to ∼ 3 GeV/c. Similar data are needed in the light meson sector for p̄p interactions in the momentum range 0.3 to 2 GeV/c. In both cases, valuable information is t...

The HERMES experiment has measured double spin asymmetries of inclusive and semi–inclusive cross sections for the production of charged hadrons in deep– inelastic scattering of polarised positrons on polarised hydrogen and deuterium targets, in the kinematic range 0.023 < x < 0.6, and 1 GeV < Q < 15 GeV. For the data taken on the deuterium target, a RICH detector provides the complete identific...

COMPASS is a fixed-target experiment on the SPS M2 beamline at CERN. Its 6 LiD target can be polarised both longitudinally and transversally with respect to the longitudinally polarised 160GeV/c µ + beam. Approximately 20% of the beam-time in 2002, 2003 and 2004 was spent in the transverse configuration, allowing the first measurement of both the Collins and Sivers asymmetries on a deuterium ta...