论文标题
电磁衰减的研究轨道激发$ξ_c$ baryons
Study of Electromagnetic Decays of Orbitally Excited $Ξ_c$ Baryons
论文作者
论文摘要
使用980 $ fb^-1 $的数据收集的数据与在Kekb非对称能源E^+E^ - 碰撞器上运行的Belle检测器，我们报告了对激发{Charmed Baryons} $ξ_c（2790）$和$ξ_c（2815）$的电磁衰变的研究。对于$ξ_c（2815）^0 \至ξ_c^0γ$，观察到明确的信号（8.6标准偏差），我们测量： $ b [ξ_c（2815）^0 \ toξ_c^0γ]/b [ξ_c（2815）^0 \ toξ_c（2645）^+π^ - \ toξ_c^0π^0π^+π^ - ] = 0.41 = 0.41 \ pm 0.05 \ pm pm 0.03 $。 我们还提供了$ξ_c（2790）^0 $的类似衰减的证据（3.8标准偏差）和测量： $ b [ξ_c（2790）^{0} \toξ_c^{0}γ]/b [ξ_c（2790）^0 \ to了ξ_c^{\ prime +}π^{ - } \ to^{ - } \ top pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm pm。 第一个引用的不确定性是统计和第二系统的。我们没有发现$ξ_c（2815）^+$和$ξ_c（2790）^+$ baryons的类似衰减的暗示，并将上限设置为90％的置信度： $ b [ξ_c（2815）^{+} \ to做大$ b [ξ_c（2790）^{+} \toξ_c^{+}γ]/b [ξ_c（2790）^+\ to了ξ_c^{\ prime 0}π^{+}π^{+} \ topeat_} \ topement} \ topement}。 提取了衰减的部分宽度的近似值，可用于区分这些激发态的基础夸克结构的模型。
Using 980 $fb^-1$ of data collected with the Belle detector operating at the KEKB asymmetric-energy e^+e^- collider, we report a study of the electromagnetic decays of excited {charmed baryons} $Ξ_c(2790)$ and $Ξ_c(2815)$. A clear signal (8.6 standard deviations) is observed for $Ξ_c(2815)^0 \to Ξ_c^0γ$, and we measure: $B[Ξ_c(2815)^0 \to Ξ_c^0γ]/B[Ξ_c(2815)^0 \to Ξ_c(2645)^+π^- \to Ξ_c^0π^+π^-] = 0.41 \pm 0.05 \pm 0.03$. We also present evidence (3.8 standard deviations) for the similar decay of the $Ξ_c(2790)^0$ and measure: $B[Ξ_c(2790)^{0}\toΞ_c^{0}γ]/B[Ξ_c(2790)^0\toΞ_c^{\prime +}π^{-}\toΞ_c^{+}γπ^-] = 0.13 \pm 0.03 \pm 0.02$. The first quoted uncertainties are statistical and the second systematic. We find no hint of the analogous decays of the $Ξ_c(2815)^+$ and $Ξ_c(2790)^+$ baryons and set upper limits at the 90% confidence level of: $B[Ξ_c(2815)^{+}\toΞ_c^{+}γ]/B[Ξ_c(2815)^+\toΞ_c(2645)^0π^+\toΞ_c^+π^-π^+] < 0.09,$ and $B[Ξ_c(2790)^{+}\toΞ_c^{+}γ]/B[Ξ_c(2790)^+\toΞ_c^{\prime 0}π^{+}\toΞ_c^{0}γπ^+] < 0.06.$ Approximate values of the partial widths of the decays are extracted, which can be used to discriminate between models of the underlying quark structure of these excited states.
