Measurement of transversity signals in two hadron production at COMPASS

The quark structure of the nucleon at the twist two level can be completely described with three quark distribution functions: the spin averaged distribution function q(x), the helicity distribution Delta q(x) and the transverse spin distribution Delta(T)q(x). This last function, referred to as transversity, is chiral-odd and can only be measured in combination with another chiral-odd function. COMPASS is a fixed target experiment at the CERN SPS M2 beamline. Its target ((6)LiD) can be both longitudinally and transversely polarized with respect to the polarized 160 GeV/c mu(+)-beam. In transverse configuration Delta(T)q(x) can be measured in semi-inclusive deep-inelastic scattering (SIDIS), requiring the detection of hadronic products. A rather new probe of the transverse spin distribution function Delta(T)q(x) is the measurement of two hadron production, introducing the chiral odd interference fragmentation function H(1)(not less than)(z, M(h)(2)). Results are presented for the years 2003-2004 including particle identification by using the information of the RICH detector. The analysis was performed using all positive/negative charged pairs andz-ordered pairs.