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-$p_T$ 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.