$A_N$ at small negative values of $\xf$ in the reaction $p+p(pol) \to   \pi^0+X$ at 70 GeV and universal threshold in inclusive pion production
  The talk continues the series of Single Spin Asymmetry (SSA) $\pi^0$ inclusive measurements carried out at Protvino 70 GeV accelerator. The asymmetry in the polarized target fragmentation region grows up in absolute value with $\xf$ decreasing and equals to $(-16 \pm 5)%$ at $-0.4<\xf<-0.25$. The result of the current experiment is in agreement with the universal threshold in pion asymmetries. 
A.M. Davidenko, A.A. Derevschikov, V.N. Grishin, V.Yu. Khodyrev, Yu.A.   Matulenko, Yu.M. Melnick, A.P. Meschanin, V.V. Moch...