Transversity distributions from difference asymmetries in semi-inclusive DIS

In recent years information on the transversity distribution h1 has been obtained by combining the Collins asymmetry results from semi-inclusive deep inelastic scattering (SIDIS) data on transversely polarized nucleon targets with the information on the fragmentation function of a transversely polarized quark from the asymmetries measured in eþe− annihilation into hadrons. An alternative method was proposed a long time ago, which does not require the eþe− data but allows one to get ratios of the u and d quark transversity distributions from the SIDIS data alone. The method utilizes the ratio of the difference of the Collins asymmetries of positively and negatively charged hadrons produced on transversely polarized proton and deuteron targets. We have applied this method to the COMPASS proton and deuteron data and extracted the ratio hdv 1 =huv 1 . The results are compared to those obtained in a previous point-by-point extraction based both on SIDIS and eþe− data.