论文标题
使用来自NASA Messenger Mission的中子光谱仪的数据对中子寿命的空间测量
Space-Based Measurement of the Neutron Lifetime using Data from the Neutron Spectrometer on NASA's MESSENGER Mission
论文作者
论文摘要
我们建立了通过一种替代的，基于空间的方法来测量中子寿命的可行性，该方法使用了星球表面和大气的银河宇宙射线剥落产生的中子。游离中子通过弱相互作用衰减，平均寿命约为880 s。这种生命周期限制了CKM基质的单位性，是研究大键核合成研究的关键参数。但是，使用两种独立方法的当前实验室测量差异超过4 $σ$。使用NASA的Messenger航天器在2007年和2008年获得的数据，该数据并非旨在进行这种测量，我们估计中子寿命为780美元\ pm60_ \ pm60_ \ textrm {stat} \ pm70_ pm70_ \ pm70_ \ pm70_ \ textrm {syst} $ s，在此启用了这一新方法。
We establish the feasibility of measuring the neutron lifetime via an alternative, space-based class of methods, which use neutrons generated by galactic cosmic ray spallation of planets' surfaces and atmospheres. Free neutrons decay via the weak interaction with a mean lifetime of around 880 s. This lifetime constrains the unitarity of the CKM matrix and is a key parameter for studies of Big-Bang nucleosynthesis. However, current laboratory measurements, using two independent approaches, differ by over 4$σ$. Using data acquired in 2007 and 2008 during flybys of Venus and Mercury by NASA's MESSENGER spacecraft, which was not designed to make this measurement, we estimate the neutron lifetime to be $780\pm60_\textrm{stat}\pm70_\textrm{syst}$ s, thereby demonstrating the viability of this new approach.
