论文标题
$ b^{ - } \toλ_{c}^{+} \barλ_{c}^{ - } k^{ - } $ decay的研究
Study of the $B^{-} \to Λ_{c}^{+} \barΛ_{c}^{-} K^{-}$ decay
论文作者
论文摘要
衰减$ b^{ - } \toλ_{c}^{+} \barλ_{c}^{ - } k^{ - } $在质子 - 质子碰撞中以$ \ sqrt {s} = 13 $ tev的数据相应的数据相关的质量为中心的质量碰撞中，该质子可以使用$ \ sqrt {s} = 13 $ tev的质量中心。 $ \ mathrm {fb}^{ - 1} $由LHCB实验收集。在$λ_{c}^+ k^{ - } $系统中，$ξ_{c}（2930）（2930）^{0} $状态在Babar and Belle实验中观察到了两个较窄的状态，$ξ_{C}（C}（c}（C}（2923）（2923）^0} $和$ and $ and $和$} $}（2）和0。测量宽度为$$ m（ξ_{c}（2923）^{0}）= 2924.5 \ pm 0.4 \ pm 1.1 \，\ mathrm {mev}，\\ m（ξ_{c} \，\ Mathrm {Mev}，\\γ（ξ_{C}（2923）^{0}）= \ phantom {000} 4.8 \ pm 0.9 \ pm 1.5 \，\ \ m athrm {mev} \ phantom {00} 11.0 \ pm 1.9 \ pm 7.5 \，\ mathrm {mev}，$$，第一个不确定性是统计的，第二个系统是系统的。结果与先前使用提示的$λ_{c}^{+} k^{ - } $样本的LHCB测量一致。 Evidence of a new $Ξ_{c}(2880)^{0}$ state is found with a local significance of $3.8\,σ$, whose mass and width are measured to be $2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV}$ and $12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}$, 分别。此外，发现新的衰减模式的证据$ξ_{c}（2790）^{0} \toλ_{c}^{+} k^{ - } $的显着性为$ 3.7 \，σ$。相对于$ b^{ - } \至λ_{c}^{+barλ_{c}^{c}^{ - } k^{ - } $相对于$ b^{ - } \ to d^{+} d^{ - } d^{ - } k^{ - pm pm的pm 0. 2 p pm的pm pm pm pm pm pm 0.2 0.25 $，第一个不确定性是统计的，第二系统和第三个起源于魅力强子衰变的分支分数。
The decay $B^{-} \to Λ_{c}^{+} \barΛ_{c}^{-} K^{-}$ is studied in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV using data corresponding to an integrated luminosity of 5 $\mathrm{fb}^{-1}$ collected by the LHCb experiment. In the $Λ_{c}^+ K^{-}$ system, the $Ξ_{c}(2930)^{0}$ state observed at the BaBar and Belle experiments is resolved into two narrower states, $Ξ_{c}(2923)^{0}$ and $Ξ_{c}(2939)^{0}$, whose masses and widths are measured to be $$ m(Ξ_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(Ξ_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ Γ(Ξ_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ Γ(Ξ_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV}, $$ where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt $Λ_{c}^{+} K^{-}$ sample. Evidence of a new $Ξ_{c}(2880)^{0}$ state is found with a local significance of $3.8\,σ$, whose mass and width are measured to be $2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV}$ and $12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}$, respectively. In addition, evidence of a new decay mode $Ξ_{c}(2790)^{0} \to Λ_{c}^{+} K^{-}$ is found with a significance of $3.7\,σ$. The relative branching fraction of $B^{-} \to Λ_{c}^{+} \barΛ_{c}^{-} K^{-}$ with respect to the $B^{-} \to D^{+} D^{-} K^{-}$ decay is measured to be $2.36 \pm 0.11 \pm 0.22 \pm 0.25$, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.
