Flavour separation of helicity distributions from deep inelastic muon-deuteron scattering

We present a LO evaluation of helicity densities of valence, Δuv+Δdv, non-strange sea, Δu¯+Δd¯, and strange quarks, Δs (assumed to be equal to Δs¯). They have been obtained from the inclusive asymmetry A1,d and the semi-inclusive asymmetries A1,dπ+, A1,dπ−, A1,dK+, A1,dK− measured in polarised deep inelastic muon-deuteron scattering. The full deuteron statistics of COMPASS (years 2002-2004 and 2006) has been used. The data cover the range Q2>1(GeV/c)2 and 0.004