Transverse spin asymmetries in p ↑ p → π± + X and lp ↑ → l′ + π± + X

✍ Scribed by Alessandro Bravar

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 208 KB
• Volume: 666-667
• Category: Article
• ISSN: 0375-9474
• DOI: 10.1016/s0375-9474(00)00044-0

✦ Synopsis

While transverse spin effects have been studied in hadronic interactions since a few decades, investigations with leptonic probes have started very recently. Azimuthal distributions of hadrons (mainly rr + and rr-) produced in DIS off transversely polarized targets (proton and deuteron) are studied for the first time in SMC. According to Collins ('Collins effect'), the azimuthal distribution of the leading hadron might exhibit an asymmetry which originates from the transverse polarization of the final quark. Large left-right spin asymmetries exist in inclusive pion production by transversely polarized proton beams: rr + (Tr-) are produced preferentially to the beam-left (beamright), when the proton spin points upwards. The pion asymmetries show an almost mirror symmetric dependence in ZF, where AN increases whith increasing XF to large values in excess of 30 % above a threshold in PT of about 0.5 GeV/c for rc + and decreases to large negative values for rr (fig. 1). For an antiproton beam, the pion asymmetries exhibit similar behaviors and magnitudes, but with reflected signs. [1]. For a recent review see [2].