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在NA64h探测器中,通过Pion产生的 η 和 η^{'} 分子无形地衰变,通过黑暗部门搜索
Yu M Andreev1, A Antonov2, M A Ayala Torres3,4
1Authors affiliated with an institute covered by a cooperation agreement with CERN.
Physical review letters
|October 7, 2024
概括
NA64h实验寻找eta和eta-prime中子的无形衰变,这是黑暗部门物理学的关键探测器. 没有发现证据,为这些罕见的衰变设定了新的极限.
科学领域:
- 粒子物理学 粒子物理学
- 实验物理实验物理学
- 宇宙学的宇宙学是什么?
背景情况:
- 黑暗部门是标准模型的假设扩展.
- 伪尺度中子 (eta和eta-prime) 可能会分解成看不见的粒子,为黑暗部门的搜索提供独特的签名.
- 之前的搜索已经限制了这些看不见的衰变,但需要新的实验技术来提高灵敏度.
研究的目的:
- 介绍第一个概念验证搜索暗区的结果,使用埃塔和埃塔主要质子的隐形衰变.
- 为了在这些看不见的衰变的分支比率上建立严格的限制.
- 为了展示一个新的实验技术的潜力,用于未来的黑暗部门搜索.
主要方法:
- 在CERN超级质子同步子 (SPS) 中利用了NA64h实验.
- 采用了一种新的技术,使用50 GeV负 pion在活性目标上的电荷交换反应来产生中性乙烯和乙烯主要质子.
- 搜索了光束能量完全消失的事件,表明无形的中子衰变.
主要成果:
- 没有观察到eta或eta-prime无形衰变的证据,目标上有2.9x10^9个pions.
- 对分支比率设置一个严格的上限 Br ((beta-prime -> invisible) < 2.1x10^-4,将现有的边界提高了大约3.3的因素.
- 建立了分支比率的上限 Br ((beta -> invisible) < 1.1x10^-4,与当前的限制相比较.
结论:
- 使用看不见的质子衰变的新技术显示了黑暗部门物理学的巨大潜力.
- 这些结果为加强未来对隐形中性子衰变的搜索提供了关键指导.
- 这项实验标志着通过罕见的质子衰变通道探测暗区候选者的重要一步.
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