论文标题
$ nd $散射长度从$λ_b\rightarrowπ^-pd^0 $ decay和$σ_c（2800）^+$的属性提取。
Extraction of $ND$ scattering lengths from the $Λ_b\rightarrowπ^-pD^0$ decay and properties of the $Σ_c(2800)^+$
论文作者
论文摘要
Isovector和Isoscalar $ nd $ $ s $ s-波散射长度是通过拟合$ pd^0 $ nd $不变质量分布的decay $λ_b\rightArrowπ^-pd^0 $中的$ pd^0 $不变质量分布来提取的，从而将cusp效应以$ nd^+$ $ $ threshold进行使用。该分析基于耦合通道非依次的有效场理论。我们发现，由于存在一个接近阈值的状态，质量约为2.8 GEV，因此等值器$ nd $散射长度的实际部分是不自然的。该状态与在Belle观察到的$σ_C（2800）^+$共振一致。我们的结果表明，它与$ s $波的$ nd $通道很强烈，其量子数为$ j^p = 1/2^ - $。可以使用更新的LHCB数据来验证$ ND^+$阈值的强尖缘行为。
The isovector and isoscalar $ND$ $s$-wave scattering lengths are extracted by fitting to the LHCb data of the $pD^0$ invariant-mass distribution in the decay $Λ_b\rightarrowπ^-pD^0$, making use of the cusp effect at the $nD^+$ threshold. The analysis is based on a coupled-channel nonrelativistic effective field theory. We find that the real part of the isovector $ND$ scattering length is unnaturally large due to the existence of a near-threshold state with a mass around 2.8 GeV. The state is consistent with the $Σ_c(2800)^+$ resonance observed at Belle. Our results suggest that it couples strongly to the $ND$ channel in an $s$-wave, and that its quantum numbers are $J^P=1/2^-$. The strong cusp behavior at the $nD^+$ threshold can be verified using updated LHCb data.
