Speaker
Christopher Braun
(Friedrich-Alexander-Univ. Erlangen (DE))
Description
The parton distribution function h1 of a transversely polarized quark inside a transversely polarized nucleon, is chiral-odd and therefore not accessible in deep inelastic scattering. It can only be observed in semi-inclusive deep inelastic scattering (SIDIS) in combination with another chiral-odd function like e.g. the two-hadron interference fragmentation function (IFF) H1. The 160 GeV/c polarized muon beam of CERN's M2 beamline allows COMPASS to investigate the production of hadrons in deep inelastic scattering using polarized solid state targets. In this contribution an overview of COMPASS results for the azimuthal asymmetries in two-hadron production on transversely polarized nucleon targets is given. This includes the results of all hadron pairs h+h- on a polarized deuteron target from the data taken in the years 2002-04, as well as the first data set on a transversely polarized proton target taken in the year 2007 and a data set taken on the same target during the year 2010 to increase precision. The COMPASS spectrometer allows a very precise particle identification, which can be used to determine the composition of the h+h- pairs in terms of pions and kaons. The results for the possible combinations, obtained very recently from the 2007 and the 2010 data, will be discussed in detail. Further the asymmetries for pion pairs will be compared to the available model predictions and the corresponding results from HERMES. These results are an important input for the extraction of h1.
Author
Christopher Braun
(Friedrich-Alexander-Univ. Erlangen (DE))
