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arXiv 0704.0630hep-ex
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用初态辐射测量的$e^+ e^-\to K^+ K^- π^+π^-$、$K^+ K^- π^0π^0$和$K^+ K^- K^+ K^-$截面

The $e^+ e^-\to K^+ K^- π^+π^-$, $K^+ K^- π^0π^0$ and $K^+ K^- K^+ K^-$ Cross Sections Measured with Initial-State Radiation

The BABAR Collaboration, B. Aubert

摘要:

研究了光子从初态辐射的过程$e^+ e^-\to K^+ K^- π^+π^-γ$、$K^+K^-π^0π^0γ$和$K^+ K^- K^+ K^-γ$。从\babar数据的232个\invfb中分别选出约34600个、4400个和2300个完全重建事件。强子末态的不变质量定义了有效的\epem质心能量,因此$K^+ K^- π^+π^-γ$数据可以与$e^+ e^-\to K^+K^- \pipi$反应的直接测量进行比较;对于$e^+ e^-\to K^+ K^- π^0π^0$或$\epem\to K^+ K^- K^+ K^-$反应,没有直接测量。通过研究这些事件的结构,我们发现了许多中间态的贡献,并在可能的情况下提取了它们的截面。特别是,我们隔离的贡献,从$e^+ e^-\toϕ(1020) f_{0}(980)$和研究其结构附近的阈值。在charmonium区域,我们观察到的$J/ψ$在所有三个最终状态和几个中间状态,以及$ψ(2S)$在某些模式,并测量相应的分支分数。我们没有看到Y(4260)的信号,并在90% C. L处获得了$\BR_{Y(4260)\toϕπ^+π^-}\cdotΓ^{Y}_{ee}<0.4 \ev$的上限。

英文摘要:

We study the processes $e^+ e^-\to K^+ K^- π^+π^-γ$, $K^+K^-π^0π^0γ$ and $K^+ K^- K^+ K^-γ$, where the photon is radiated from the initial state. About 34600, 4400 and 2300 fully reconstructed events, respectively, are selected from 232 \invfb of \babar data. The invariant mass of the hadronic final state defines the effective \epem center-of-mass energy, so that the $K^+ K^- π^+π^-γ$ data can be compared with direct measurements of the $e^+ e^-\to K^+K^- \pipi$ reaction; no direct measurements exist for the $e^+ e^-\to K^+ K^- π^0π^0$ or $\epem\to K^+ K^- K^+ K^-$ reactions. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from $e^+ e^-\toϕ(1020) f_{0}(980)$ and study its structure near threshold. In the charmonium region, we observe the $J/ψ$ in all three final states and several intermediate states, as well as the $ψ(2S)$ in some modes, and measure the corresponding branching fractions. We see no signal for the Y(4260) and obtain an upper limit of $\BR_{Y(4260)\toϕπ^+π^-}\cdotΓ^{Y}_{ee}<0.4 \ev$ at 90% C.L.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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