论文标题
Charmed-Strange Baryon的旋转和均等的首次确定,$ξ_{C}(2970)^+$
First Determination of the Spin and Parity of a Charmed-Strange Baryon, $Ξ_{c}(2970)^+$
论文作者
论文摘要
我们通过使用$ 980〜 \ Mathrm {fb^{ - 1}} $数据样本在Kekb kekb bemmetric-Energy-Energy-Energy $ e^{+e^+clider中收集的$ 980〜 \ Mathrm {fb^{ - 1}} $数据样本,从$ 980〜 \ mathrm {fb^{ - 1} $数据样本报告了$ 980〜 \ mathrm {fb^{ - 1} $数据样本的研究结果。链条$ξ_{c}(2970)^+\ toξ_c(2645)^{0}π^{+} \至ξ_c^{+}π^{ - }π^{ - }π^{+} $在分析此启发的baryon。在假设最低的部分波在衰减中占主导地位,角度分布强烈利用$ξ_{c}(2970)^+$ spin $ j = 1/2 $或$ 5/2 $,或$ 5/2 $。我们还测量了$ξ_{C}(2970)^+$衰减分支的比率$ r = {\ Mathcal {b} [ξ_{c}(2970)^+\ toξ_c(2645) ξ_{c}(2970)^+\ toξ_c^{\ prime0}π^{+}]} = 1.67 \ pm 0.29 \ pm 0.29 \ mathrm {(stat。 0.25 \ mathrm {(is)} $,其中最后一个不确定性是由于可能的isospin-ymmetry-Mebletry-Mebletry-Mebletry-Mebletry效果。这个$ r $ value有利于自由度自由度的自旋旋转$ j^p = 1/2^+$。这是诱人的爆发baryon的自旋和奇偶校验的首次确定。
We report results from a study of the spin and parity of $Ξ_{c}(2970)^+$ using a $980~\mathrm{fb^{-1}}$ data sample collected by the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. The decay angle distributions in the chain $Ξ_{c}(2970)^+ \to Ξ_c(2645)^{0}π^{+} \to Ξ_c^{+}π^{-}π^{+}$ are analyzed to determine the spin of this charmed-strange baryon. The angular distributions strongly favor the $Ξ_{c}(2970)^+$ spin $J =1/2$ over $3/2$ or $5/2$, under an assumption that the lowest partial wave dominates in the decay. We also measure the ratio of $Ξ_{c}(2970)^+$ decay branching fractions $R={\mathcal{B}[ Ξ_{c}(2970)^+ \to Ξ_c(2645)^{0}π^{+} ]} / { \mathcal{B}[ Ξ_{c}(2970)^+ \to Ξ_c^{\prime0}π^{+} ]} =1.67 \pm 0.29\mathrm{(stat.)}^{ +0.15}_{ -0.09}\mathrm{(syst.)} \pm 0.25\mathrm{(IS)}$, where the last uncertainty is due to possible isospin-symmetry-breaking effects. This $R$ value favors the spin-parity $J^P=1/2^+$ with the spin of the light-quark degrees of freedom $s_{l}=0$. This is the first determination of the spin and parity of a charmed-strange baryon.