Eur. Phys. J. C 18, 639-644
DOI: 10.1007/s100520100564

Transversity distribution and polarized fragmentation function from semi-inclusive pion electroproduction

V.A. Korotkov^{1, 2}, W.-D. Nowak² and K.A. Oganessyan<sup>2, 3, 4

1</sup>  IHEP, 142284 Protvino, Russia
²  DESY Zeuthen, 15738 Zeuthen, Germany
³  INFN, Laboratori Nazionali di Frascati, 00044 Frascati, Italy
⁴  Yerevan Physics Institute, 375036 Yerevan, Armenia

(Received: 18 June 2000 / Revised version: 20 November 2000 / Published online: 5 February 2001 -© Springer-Verlag 2001)

Abstract
A method is discussed to determine the hitherto unknown u-quark transversity distribution from a planned HERMES measurement of a single target-spin asymmetry in semi-inclusive pion electroproduction off a transversely polarized target. Assuming u-quark dominance, the measurement yields the shapes of the transversity distribution and of the ratio , of polarized and unpolarized u-quark fragmentation functions. The unknown relative normalization can be obtained by identifying the transversity distribution with the well-known helicity distribution at large x and small Q². The systematic uncertainty of the method is dominated by the assumption of u-quark dominance.

© Società Italiana di Fisica, Springer-Verlag 2001