arXiv subjects
Publications and source records attributed to N. S. Borisov.
We present recent results of single-spin asymmetry $A_N$ measurements in $π^0$ inclusive production. Asymmetry was measured in $π^-p$ and $pp$ interactions at 40 and 70 GeV correspondingly. Significant asymmetry was observed in the polarized target fragmentation region. The results are in agreement with "universal threshold" of single-spin asymmetry.
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 $-(13.8\pm 3.8)%$.
The talk continues the series of Single Spin Asymmetry (SSA) $π^0$ 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 new measurement of $Δσ_T$ for polarized neutrons transmitted through a polarized proton target at 16.2 MeV has been made. A polarized neutron beam was obtained from the $^{3}\rm{H}(d,\vec n)^{4}\rm{He}$ reaction; proton polarization over 90\% was achieved in a frozen spin target of 20 cm$^3$ volume. The measurement yielded the value $Δσ_T=(-126\pm21\pm14)$ mb. The result of a simple phase shift analysis for the $^3S_1-^3D_1$ mixing parameter $ε_1$ is presented and compared with the theoretical potential model predictions.