Relatore
Descrizione
Data from Belle Collaboration for associated (with a light unpolarized hadron) and single-inclusive production of transversely polarized $\Lambda$-hyperons in $e^+e^-$ annihilation processes allowed to extract, for the first time, the $\Lambda$ polarizing fragmentation function, by adopting a simplified TMD approach. Recent theoretical developments on the computation of cross sections for single-inclusive hadron production in $e^+e^-$ annihilation, within a Soft Collinear Effective Theory approach, combined with the CSS formalism for the double-hadron production case, have been used to perform a renewed analysis, adopting a proper TMD factorization scheme. A detailed a comparison with the former analysis will be discussed. Preliminary estimates for the transverse $\Lambda$ polarization at OPAL and at $\sqrt s = M_Z$ will also be presented.
