论文标题
在Cern SPS搜寻X17玻色子
Hunting down the X17 boson at the CERN SPS
论文作者
论文摘要
最近，Atomki实验报告了新的证据，证明了$ e^+ e^ - $ $ \ sim $ \ sim $ 17 MEV的核转换中的$^4 $ HE，他们以前在用$^8 $ BE的测量中观察到。这些观察结果可以用新的矢量$ x17 $ boson来解释。到目前为止，搜索衰减$ x17 \ rightarrow e^+ e^ - $ $ $ $ $ $在Cern SPS的Na64实验给出了负面结果。在这里，我们提出了一种可以在NA64中实施的新技术，旨在提高灵敏度并覆盖其余$ x17 $的参数空间。如果检测到信号状事件，则通过使用建议的方法重建$ x17 $衰减的不变质量来实现明确的观察。为了实现这一目标，需要优化$ x17 $的生产目标，以及对两个近距离衰减轨道的有效，准确的重建。提出了对可用实验数据使用跟踪器信息的专门分析。该方法提供了NA64已发布结果的独立确认[物理学。 Rev. D101，071101（2020）]，验证了跟踪过程。对拟议设置和背景估计的详细蒙特卡洛研究表明，拟议搜索的目标是可行的。
Recently, the ATOMKI experiment has reported new evidence for the excess of $e^+ e^-$ events with a mass $\sim$17 MeV in the nuclear transitions of $^4$He, that they previously observed in measurements with $^8$Be. These observations could be explained by the existence of a new vector $X17$ boson. So far, the search for the decay $X17 \rightarrow e^+ e^-$ with the NA64 experiment at the CERN SPS gave negative results. Here, we present a new technique that could be implemented in NA64 aiming to improve the sensitivity and to cover the remaining $X17$ parameter space. If a signal-like event is detected, an unambiguous observation is achieved by reconstructing the invariant mass of the $X17$ decay with the proposed method. To reach this goal an optimization of the $X17$ production target, as well as an efficient and accurate reconstruction of two close decay tracks, is required. A dedicated analysis of the available experimental data making use of the trackers information is presented. This method provides independent confirmation of the NA64 published results [Phys. Rev. D101, 071101 (2020)], validating the tracking procedure. The detailed Monte Carlo study of the proposed setup and the background estimate shows that the goal of the proposed search is feasible.
