Single spin asymmetry measurements for $π^0$ inclusive productions in $p+p_{\uparrow} \to π^0 + X$ and $π^-+\p_{\uparrow}\to π^0+X$ reactions at 70 and 40 GeV respectively

Abstract

The inclusive $π^0$ asymmetries were measured in reactions $p+p\uparrow \to π^0+X$ and $π^-+p\uparrow \to π^0+X$ at 70 and 40 GeV/c respectively. The measurements were made at the central region (for the first reaction) and asymmetry is compatible with zero in the entire measured $p_T$ region. For the second reaction the asymmetry is zero for small $x_F$ region ($-0.4<x_F<-0.1, 0.5<p_T(GeV/c) <1.5$) and increases with growth of $\mid x_F\mid$. Averaged over the interval $-0.8<x_F<-0.4, 1<p_T(GeV/c)<2$ the asymmetry was $-(13.8\pm 3.8)%$.