ar X iv : h ep - p h / 01 06 26 0 v 1 2 3 Ju n 20 01 SINGLE - SPIN ASYMMETRIES AND SOFT - GLUON POLES
نویسنده
چکیده
The interest in the single transverse spin asymmety AN in the pion production, N(P, S⊥)+N(P ) → π(lT )+X , and the hyperon (typically Λ) polarization PΛ in the unpolarized NN collision, N(P ) +N(P ) → Λ(lT , S⊥) +X , resides in the fact that they probe quark-gluon correlation in the hadrons (higher twist effect) which is not included in the parton model. Without it, the partonic cross sections are strongly suppressed by mq/Q (mq is a quark mass and Q is a hard scale involved) and gives negligible asymmetries. In this talk, I will discuss AN and PΛ in the framework of the collinear factorization. According to the generalized QCD factorization theorem, the cross section for AN typically consists of three kinds of twist-3 cross sections,
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تاریخ انتشار 2001