rad-lab seminar

by Dr Charlotte Van Hulse (University of the Basque Country)

Monday 14 May 2012, 13:00 → 14:30 Asia/Tokyo

535-537 (Main Research Building)

Charlotte Van Hulse (University of the Basque Country) "Hadronization studies at HERMES" DATE : May 14 (Mon) 13:00-14:30 PLACE : Main Research Building 535,537 (研究本館） 初田研セミナーと時間がかぶってしまい申し訳ありませんが、 ご興味のあるかたは参加いただけると幸いです。 よろしくお願いします。 abstract: The HERMES experiment at DESY, Hamburg, collected data using the 27.6 GeV HERA electron/positron beam incident on a variety of gaseous tar- gets, among others transversely polarized and unpolarized hydrogen as well as unpolarized deuterium, neon, krypton, and xenon. From the data taken with the hydrogen and deuterium targets charge-separated kaon and pion multiplicities in semi-inclusive deep-inelastic scattering were extracted. These allow the study of the spin-independent fragmentation of quarks into the identified hadrons. Hadronization in the nuclear environment studied via the analysis of multiplic- ities provides additional qualitative information on the space-time evolution of hadron formation. From the analysis of the azimuthal distribution of the pro- duced hadrons spin effects in hadronization can be studied, in particular the Collins fragmentation function, which describes the formation of a transversely polarized quark into an unpolarized hadron. The latter fragmentation function can also be accessed independently analyzing semi-inclusive deep-inelastic scat- tering events using the transversely polarized hydrogen target. The study of two-pion production from this same data sample provides access to the inter- ference fragmentation function, in which the transverse spin of the fragmenting quark is transferred to the relative orbital angular momentum of the hadron pair. An overview of the results of the mentioned analyses as well as their possible interpretations will be presented.