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Particles and Fields


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

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

V.A. Korotkov1, 2, W.-D. Nowak2 and K.A. Oganessyan2, 3, 4

1  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 $\delta u(x)$ 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 $\delta u(x)$ and of the ratio $H_1^{\perp (1)u}(z)/D_1^u(z)$, 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