  We present an updated extraction of the transversity parton distribution
based on the analysis of pion-pair production in deep-inelastic scattering off
transversely polarized targets in collinear factorization. Data for proton and
deuteron targets make it possible to perform a flavor separation of the valence
components of the transversity distribution, using di-hadron fragmentation
functions taken from the semi-inclusive production of two pion pairs in
back-to-back jets in e+e- annihilation. The e+e- data from Belle have been
reanalyzed using the replica method and a more realistic estimate of the
uncertainties on the chiral-odd interference fragmentation function has been
obtained. Then, the transversity distribution has been extracted by using the
most recent and more precise COMPASS data for deep-inelastic scattering off
proton targets. Our results represent the most accurate estimate of the
uncertainties on the valence components of the transversity distribution
currently available.
