通过 $e^+e^-\to J/\psi\to\Lambda\overline\Lambda$ 测量非弹性散射 $\Lambda(\overline\Lambda)+p\to\Sigma^{0}(\overline\Sigma^{0})+p$
Measurement of inelastic scattering $Λ(\overlineΛ)+p\toΣ^{0}(\overlineΣ^{0})+p$ via $e^+e^-\to J/ψ\toΛ\overlineΛ$
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中文总结 AI 辅助
本研究利用BESIII的$J/\psi$数据，以衰变超子为束流、束流管材料为靶，测量了$\Lambda$和$\overline\Lambda$与质子的非弹性散射截面，首次观测到反超子重子末态非弹性散射，为超子-核子相互作用提供新约束。
中文摘要 AI 辅助
利用BESIII探测器收集的$(10087\pm44)\times10^{6}$个$J/\psi$事件样本，我们将$J/\psi\to\Lambda\overline\Lambda$衰变产生的超子作为有效束流，以束流管材料为靶，研究了$\Lambda+p\to\Sigma^{0}+p$和$\overline\Lambda+p\to\overline\Sigma^{0}+p$非弹性散射过程。在超子动量为$1.074~\mathrm{GeV}/c$的条件下，测量得到$\Lambda+{}^{9}\mathrm{Be}\to\Sigma^{0}+p+{}^{8}\mathrm{Li}$和$\overline\Lambda+{}^{9}\mathrm{Be}\to\overline\Sigma^{0}+p+{}^{8}\mathrm{Li}$过程的截面分别为$(10.1\pm1.4_{\rm stat}\pm0.7_{\rm syst})$ mb和$(1.7\pm0.6_{\rm stat}\pm0.4_{\rm syst})$ mb。在超子-原子核散射以表面贡献为主的假设下，这些测量结果被用于提取对应的质子靶截面。此外，利用束流管油中的氢成分直接测量得到$\Lambda+p\to\Sigma^{0}+p$的截面为$(3.2\pm1.1_{\rm stat}\pm0.5_{\rm syst})$ mb，$\overline\Lambda+p\to\overline\Sigma^{0}+p$的截面为$(1.5\pm0.5_{\rm stat}\pm0.1_{\rm syst})$ mb，与间接测定结果一致。两者的组合截面分别为$(4.7\pm0.7)$ mb和$(1.1\pm0.3)$ mb。$\overline\Lambda+p\to\overline\Sigma^{0}+p$信号的显著性为$3.1\sigma$，是反超子与重子末态非弹性散射的首个证据。$\Lambda p$与$\overline\Lambda p$非弹性散射截面的显著差异为超子-核子和反超子-核子相互作用提供了新的实验约束。
英文摘要
Using a sample of $(10087\pm44)\times10^{6}$ $J/ψ$ events collected with the BESIII detector, we investigate the inelastic scattering processes $Λ+p\toΣ^{0}+p$ and $\overlineΛ+p\to\overlineΣ^{0}+p$, exploiting hyperons from $J/ψ\toΛ\overlineΛ$ decays as an effective beam and the beam-pipe materials as targets. The processes $Λ+{}^{9}\mathrm{Be}\toΣ^{0}+p+{}^{8}\mathrm{Li}$ and $\overlineΛ+{}^{9}\mathrm{Be}\to\overlineΣ^{0}+p+{}^{8}\mathrm{Li}$ are measured at a hyperon momentum of $1.074~\mathrm{GeV}/c$, with cross sections of $(10.1\pm1.4_{\rm stat}\pm0.7_{\rm syst})$ mb and $(1.7\pm0.6_{\rm stat}\pm0.4_{\rm syst})$ mb, respectively. Under the assumption of surface-dominated hyperon-nucleus scattering, these measurements are used to extract the corresponding proton-target cross sections. Independently, direct measurements using the hydrogen component of the beam-pipe oil yield $(3.2\pm1.1_{\rm stat}\pm0.5_{\rm syst})$ mb for $Λ+p\toΣ^{0}+p$ and $(1.5\pm0.5_{\rm stat}\pm0.1_{\rm syst})$ mb for $\overlineΛ+p\to\overlineΣ^{0}+p$, consistent with the indirect determinations. The combined cross sections are $(4.7\pm0.7)$ mb and $(1.1\pm0.3)$ mb, respectively. The $\overlineΛ+p\to\overlineΣ^{0}+p$ signal constitutes the first evidence for anti-hyperon inelastic scattering with baryonic final states, with a significance of $3.1σ$. The pronounced difference between the $Λp$ and $\overlineΛp$ inelastic scattering cross sections provides new experimental constraints on hyperon-nucleon and anti-hyperon-nucleon interactions.
