Speaker
Christian Schill
(Univ. Freiburg)
Description
An important missing piece in our understanding of the spin structure of the
nucleon is the transversity distribution function Delta_Tq(x). It is only
one of the three leading-twist quark distribution functions q(x), Delta q(x)
and Delta_Tq(x) that so-far remains unmeasured. The function Delta_Tq(x)
describes the distribution of transversely polarized quarks in a transversely
polarized nucleon. It is difficult to measure Delta_Tq(x), since it is a
chiral-odd function which can only be probed in combination with another
chiral-odd function. One suggested probe to access transversity is the
measurement of two-hadron production in semi-inclusive deep-inelastic
scattering on a transversely polarized target. In this case, transversity is
accessible via the chiral-odd two-hadron interference fragmentation function
H_1^\sphericalangle(z,M_h^2). The COMPASS experiment has measured target
single-spin asymmetries in semi-inclusive production of hadron pairs. The data
presented have been taken scattering a 160 GeV muon beam off a transversely
polarized deuterium target. The scattered hadrons have been identified as pions
and kaons using the information of a ring imaging Cherenkov detector. The
azimuthal asymmetries are presented as a function of the invariant mass of the
hadron pairs and in dependence of the kinematic variables x_{Bj} and z.
Author
Christian Schill
(Univ. Freiburg)
