Mainz 2012 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 23: Hadronenstruktur und -spektroskopie
HK 23.6: Vortrag
Mittwoch, 21. März 2012, 15:30–15:45, RW 2
COMPASS results on transverse spin asymmetries in two-hadron production in SIDIS — •Christopher Braun — Physikalisches Institut IV der Universität Erlangen-Nürnberg
At twist-two level the nucleon and its quark content can exist in three states regarding their polarizations in the collinear case: both can be unpolarized, longitudinally or transversely polarized. This refers to three independent parton distribution functions (PDF) for each quark flavour q: the quark distribution f1q(x), the helicity distribution g1q(x) and the transversity distribution h1q(x) = qq↑↑(x) − qq↑↓(x). Where ↑↑ means quark spin parallel and ↑↓ antiparallel to the spin of the nucleon. The transversity function is chiral-odd and therefore is not accessible in deep inelastic scattering (DIS). However, h1q(x) can be observed in semi-inclusive DIS in combination with another chirally odd function like the two-hadron interference fragmentation function (IFF) H1,q in two-hadron production, which is the subject of this contribution. The 160 GeV/c polarized µ+ beam of CERN’s M2 beamline allows COMPASS to investigate the spin structure of the nucleon using polarized solid state targets. After taking the first data on a transversely polarized proton target (NH3) in 2007, a full year of data taking followed in 2010 to increase precision. In this contribution the latest results from the 2010 data for the azimuthal asymmetries in two-hadron production are presented. An extraction of h1q(x) via a coupling to the two-hadron IFF H1,q has been carried out for the 2007 data.
supported by German BMBF