Spin structure of hadrons in supersymmetric quantum chromodynamics at short distances

Abstract

We study the short-distance spin structure of nucleons in supersymmetric QCD. We calculate the Altarelli-Parisi spin transition coefficients ΔP ba and corresponding anomalous Δ γ ab n fora, b=quarks, gluons, gluinos and squarks and present the supersymmetric relations between them. Further analysis is divided into two parts: the parity conserving case and parity violating case, both following from the mass mixing in the squark sector. Solving theQ 2-evolution equations we determine the quark, gluon, gluino and squark spin distribution at variousQ 2 above the threshold for production of supersymmetric partners. We also show the analytic solutions for the first moments in the nonsinglet and singlet sector. In particular the spin carried by the valence quarks turn out to vanish asymptotically except of one particular case of squark mixing.