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arXiv 1012.3781nucl-thhep-ph
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对$Θ^+$五夸克态的批判性看法

Critical view of the claimed $Θ^+$ pentaquark

E. Oset, A. Martinez Torres

摘要:

我们使用的$γ~d \to ~K^+ K^- ~n ~p $反应的理论模型,适用于在LEPS进行的实验,在那里观察到一个峰,并与$Θ^{+}(1540)$五夸克。该研究表明,在实验中使用的方法,关联动量的未检测到的质子和中子,连同所选择的削减,必然会创建一个人工宽峰在该地区的要求$Θ^{+}(1540)$在假定的$K^+ n$不变质量。它表明,LEPS适合的数据,用于使索赔的$Θ^{+}(1540)$,严重扭曲的背景。另一种拟合,假设背景加波动,返回的背景实际上等于理论值,波动与2 $σ$显著性的实验$K^- p$光谱中观察到的波动相同。

英文摘要:

We use a theoretical model of the $γ~d \to ~K^+ K^- ~n ~p $ reaction adapted to the experiment done at LEPS where a peak was observed and associated to the $Θ^{+}(1540)$ pentaquark. The study shows that the method used in the experiment to associate momenta to the undetected proton and neutron, together with the chosen cuts, necessarily creates an artificial broad peak in the assumed $K^+ n$ invariant mass in the region of the claimed $Θ^{+}(1540)$. It is shown that the LEPS fit to the data, used to make the claim of the $Θ^{+}(1540)$, grossly distorts the background. An alternative fit, assuming a background plus a fluctuation, returns a background practically equal to the theoretical one and a fluctuation identical to the one seen in the experimental $K^- p$ spectrum of 2$σ$ significance.

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