论文标题
在新的精确光束不对称$σ$数据中观察$pη'$ cusp的$γp\ topη$
Observation of the $pη'$ Cusp in the New Precise Beam Asymmetry $Σ$ Data for $γp\to p η$
论文作者
论文摘要
据报道，在1130至1790 MEV的标记光子能量中，质量$η$ erson的光增生的光束不对称$σ$的数据（从$ W = $ 1748 MEV到$ W = $ 2045 MEV）。数据涵盖了完整的实体角度，可以进行精确的力矩分析。首次观察到在两极分化中的强烈尖端效应是在$pη'$阈值下的分支点奇异性的效果[$e_γ= $ 1447 meV（$ w = $ 1896 meV）]。最新的BNGA局部波分析包括新的束不对称数据，并产生了$ N（1895）\ frac {1} {1} {2}^ - $ nucleon共振的强烈指示，这表明了所有奇异性的重要性，以正确确定部分波和共振参数。
Data on the beam asymmetry $Σ$ in the photoproduction of $η$ mesons off protons are reported for tagged photon energies from 1130 to 1790 MeV (mass range from $W=$ 1748 MeV to $W=$ 2045 MeV). The data cover the full solid angle that allows for a precise moment analysis. For the first time, a strong cusp effect in a polarization observable has been observed that is an effect of a branch-point singularity at the $pη'$ threshold [$E_γ=$ 1447 MeV ($W=$ 1896 MeV)]. The latest BnGa partial wave analysis includes the new beam asymmetry data and yields a strong indication for the $N(1895)\frac{1}{2}^-$ nucleon resonance, demonstrating the importance of including all singularities for a correct determination of partial waves and resonance parameters.
