Seoul National University, Seoul 151-742.
Phys Rev Lett. 2013 May 31;110(22):222002. doi: 10.1103/PhysRevLett.110.222002.
We report the results of a high-statistics search for H dibaryon production in inclusive Υ(1S) and Υ(2S) decays. No indication of an H dibaryon with a mass near the M(H)=2m(Λ) threshold is seen in either the H→Λpπ(-) or ΛΛ decay channels and 90% confidence level branching-fraction upper limits are set that are between one and two orders of magnitude below the measured branching fractions for inclusive Υ(1S) and Υ(2S) decays to antideuterons. Since Υ(1S,2S) decays produce flavor-SU(3)-symmetric final states, these results put stringent constraints on H dibaryon properties. The results are based on analyses of 102 million Υ(1S) and 158 million Υ(2S) events collected with the Belle detector at the KEKB e(+)e(-) collider.
我们报告了在 Υ(1S) 和 Υ(2S) 衰变中寻找 H 双介子产生的高统计搜索结果。在 H→Λpπ(-) 或 ΛΛ 衰变道中都没有观察到质量接近 M(H)=2m(Λ) 阈值的 H 双介子的迹象，并且设定了 90%置信水平的分支比上限，它们比测量到的 Υ(1S) 和 Υ(2S) 衰变到反氘核的分支比上限低一个到两个数量级。由于 Υ(1S,2S) 衰变产生 flavor-SU(3)-对称的末态，这些结果对 H 双介子的性质施加了严格的限制。这些结果是基于 Belle 探测器在 KEKB e(+)e(-) 对撞机上收集的 1020 万 Υ(1S) 和 1580 万 Υ(2S) 事件的分析得出的。
