Estimate of a chiral-odd contribution to single transverse-spin asymmetry in hadronic pion production

We present an estimate of a chiral-odd contribution to the single transverse spin asymmetry in the large-pT pion production in the nucleon-nucleon collision. In this contribution the transversity distribution and the chiral-odd spin-independent twist-3 distribution appear. Because of the smallness of the corresponding hard cross section, this term turned out to be negligible in all kinematic regions compared with the chiral-even contribution.