论文标题
搜索$ c \!p $违反和测量分支分数和衰减不对称参数的$λ_c^+\toλh^+$和$λ_c^+\toς^+x {0} h^+$($ h^+$($ h \!= \!= \!
Search for $C\!P$ violation and measurement of branching fractions and decay asymmetry parameters for $Λ_c^+\toΛh^+$ and $Λ_c^+\toΣ^{0} h^+$ ($h\!=\!K,\,π$)
论文作者
论文摘要
我们报告了$λ_c^+\toλh^+$和$λ_c^+\toς^{0} h^+$($ h \!= \!= \! $ e^+e^ - $ collider。测量了两种cabbbo抑制的直接$ c \!p $不对称的结果(scs)诱人的bary子的衰变,$ a_ {c \!美元我们还对四种感兴趣模式的衰减不对称参数($α$)进行了最精确的测量,并通过$α$诱导的$ c \!p $ symmetry($ a_ {c \!p}^α$)搜索$ c \!p $违规。我们测量$ a_ {c \! 0.35 \ pm 0.14} $,这是第一个$ a_ {c \!p}^α$结果,用于Charmed Baryons的SCS衰变。我们在$λ_c^+\ to中搜索$λ$ -Hyperon $ c \!p $违规,to(λ,\,σ^0)π^+$,找到$ a_ {c \!这是Hyperon $ c \!P $违规第一次是通过Cabibbo最喜欢的魅力衰减来衡量的。找不到BARYON $ C \!P $违规的证据。我们还获得了两个SCS $λ_C^+$衰减的最精确的分支分数,$ \ MATHCAL {B}(λ_C^+\toλk^+)\!= \!(6.57 \ pm0.17 \ pm0.17 \ pm0.1111 \ pm0.11 \ pm0.35) $ \ MATHCAL {b}(λ_c^+\toς^0k^+)\!= \!(3.58 \ pm0.19 \ pm0.06 \ pm0.19)\ times10^{ - 4} $。第一个不确定性是统计的,是第二系统的,而第三个不确定性来自$λ_C^+\ to(λ,\,σ^0)π^+$的世界平均分支分支的不确定性。
We report a study of $Λ_c^+\toΛh^+$ and $Λ_c^+\toΣ^{0} h^+$ ($h\!=\!K,\,π$) decays based on a data sample of 980~${\rm fb}^{-1}$ collected with the Belle detector at the KEKB energy-asymmetric $e^+e^-$ collider. The first results of direct $C\!P$ asymmetry in two-body singly Cabibbo-suppressed (SCS) decays of charmed baryons are measured, $A_{C\!P}^{\rm{dir}}(Λ_c^+\toΛK^+)\!=\!+0.021\pm0.026\pm0.001$ and $A_{C\!P}^{\rm{dir}}(Λ_c^+\toΣ^0K^+)\!=\!+0.025\pm0.054\pm0.004$. We also make the most precise measurement of the decay asymmetry parameters ($α$) for the four modes of interest and search for $C\!P$ violation via the $α$-induced $C\!P$ asymmetry ($A_{C\!P}^α$). We measure $A_{C\!P}^α(Λ_c^+\toΛK^+)\!=\!{-0.023\pm0.086\pm0.071}$ and $A_{C\!P}^α(Λ_c^+\toΣ^0K^+)\!=\!{+0.08\pm 0.35\pm 0.14}$, which are the first $A_{C\!P}^α$ results for SCS decays of charmed baryons. We search for $Λ$-hyperon $C\!P$ violation in $Λ_c^+\to(Λ,\,Σ^0)π^+$ and find $A_{C\!P}^α(Λ\to pπ^{-})\!=\!{+0.013\pm0.007\pm0.011}$. This is the first time that hyperon $C\!P$ violation has been measured via Cabibbo-favored charm decays. No evidence of baryon $C\!P$ violation is found. We also obtain the most precise branching fractions for two SCS $Λ_c^+$ decays, $\mathcal{B}(Λ_c^+\toΛK^+)\!=\!(6.57\pm0.17\pm0.11\pm0.35)\times10^{-4}$ and $\mathcal{B}(Λ_c^+\toΣ^0K^+)\!=\!(3.58\pm0.19\pm0.06\pm0.19)\times10^{-4}$. The first uncertainties are statistical and the second systematic, while the third uncertainties come from the uncertainties on the world average branching fractions of $Λ_c^+\to(Λ,\,Σ^0)π^+$.