论文标题
重新访问过渡$ξ^{+} _ {cc} \toξ^{（'）+} _ c $从LHCB了解数据
Revisiting the transition $Ξ^{+}_{cc}\toΞ^{(')+}_c$ to understand the data from LHCb
论文作者
论文摘要
LHCB的合作新近测量了双重迷人的Baryon $ξ^{++} _ {cc} \ to配给^{'+}π^+$的衰减率，其分支分数的比例与衰减$ξ^{++} _ {cc} _ {cc} \ cc}^+}^+} $ 1.41 \ pm 0.17 \ pm 0.10 $。该结果与几个小组的理论预测相抵触。在我们先前的工作中，按照早期文献的处方，$ us $ diquark in $ξ^{+} _ {c} $被假定为标量，而$ξ^{'+} _ {c} $是$} $} $} $} $} $} $的旋转结构。 $ξ^{'+} _ {c} $是$ [us] _1 c $，我们研究了$ξ^{++} _ {cc} \ to了ξ^{（'）+} $的情况。从数值上讲，我们获得了$γ（ξ^{++} _ {cc} \ to了ξ^{'+}π^+）/γ（蒜在放弃预设的同时，我们假设$ us $ $ $ $ in $中的自旋量结构可能是标量和矢量的混合物，即$之一的旋转效果，+} _ {c} _ {c} $ { sin}θ\，[us] _ {1} [c] $。替代组合$ - {\ rm sin}θ\，[us] _ {0} [C]+{\ rm cos}θ\，[us] _ {1} [c] $将对应于$之一引入混合机制$γ（ξ^{++} _ {cc} \ TOTC} \ TOTC^{'+}π^+）/γ（ξ^{++} _ {cc} _ {cc} \ top topec} \ top topec} \ top topect^{+} {+} {+} {+}π^+）$取决于混合角度$θ$。在混合方案的情况下，理论预测$ξ^{+} _ {+} _ {cc} \to葱$θ= 16.27^\ circ \ pm2.30^\ circ $或$ 85.54^\ circ \ pm2.30^\ circ $已设置。毫无疑问，在测试混合机制并进一步确定混合角度时，迫切需要更精确的测量值。
The LHCb collaboration newly measured the decay rate of doubly charmed baryon $Ξ^{++}_{cc}\toΞ^{'+}π^+$ and a ratio of its branching fraction with respect to that of the decay $Ξ^{++}_{cc}\toΞ^{+}π^+$ is reported as $1.41\pm 0.17\pm 0.10$. This result conflicts with the theoretical predictions made by several groups. In our previous work, following the prescription given in early literature where the $us$ diquark in $Ξ^{+}_{c}$ is assumed to be a scalar whereas in $Ξ^{'+}_{c}$ is a vector i.e. the spin-flavor structure of $Ξ^{+}_{c}$ is $[us]_0 c$ and that of $Ξ^{'+}_{c}$ is $[us]_1 c$, we studied the case of $Ξ^{++}_{cc}\toΞ^{(')+}$ with the light front quark model. Numerically we obtained $Γ(Ξ^{++}_{cc}\toΞ^{'+}π^+)/Γ(Ξ^{++}_{cc}\toΞ^{+}π^+)=0.56\pm0.18$ which is about half of the data. While abandoning the presupposition, we suppose the spin-flavor structure of $us$ in $Ξ^{+}_{c}$ may be a mixture of scalar and vector, namely the spin-flavor function of $Ξ^{+}_{c}$ could be ${\rm cos}θ\, [us]_{0}[c]+{\rm sin}θ\, [us]_{1}[c]$. An alternative combination $-{\rm sin}θ\,[us]_{0}[c]+{\rm cos}θ\, [us]_{1}[c]$ would correspond to $Ξ^{'+}_{c}$. Introducing the mixing mechanism the ratio $Γ(Ξ^{++}_{cc}\toΞ^{'+}π^+)/Γ(Ξ^{++}_{cc}\toΞ^{+}π^+)$ depends on the mixing angle $θ$. With the mixing scenario, the theoretical prediction on the ratio between the transition rate of $Ξ^{+}_{cc}\toΞ^{'+}_c$ and that of $Ξ^{+}_{cc}\toΞ^{+}_c$ can coincide with the data as long as $θ=16.27^\circ\pm2.30^\circ$ or $85.54^\circ\pm2.30^\circ$ is set. Definitely, more precise measurements on other decay portals of $Ξ^{+}_{cc}$ are badly needed for testing the mixing mechanism and further determining the mixing angle.
