Electron-beam energy reconstruction for neutrino oscillation measurements.
Electron-beam energy reconstruction for neutrino oscillation measurements.
复制标题
用于中微子振荡测量的电子束能量重建。
DOI：
10.1038/s41586-021-04046-5
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发表时间：
2021
期刊：
影响因子：
64.8
通讯作者：
Khachatryan M
中科院分区：
文献类型：
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作者：
Khachatryan M
中微子存在于三种类型或“味道”中的一种电子中微子、μ子中微子和τ中微子，当它们在空间中传播时，会从一种味道振荡到另一种味道。这种现象是为数不多的不能用粒子物理学标准模型描述的现象之一，因此它的实验研究可以为我们的宇宙性质提供新的见解。中微子的振荡是它们的传播距离（L）除以它们的能量（E）的函数。因此，实验通过测量它们在不同位置处的能量分布来提取振荡参数。由于基于加速器的振荡实验不能直接测量E，这些实验的解释在很大程度上依赖于中微子-核相互作用的唯象模型来推断E。在这里，我们利用电子与原子核和中微子与原子核相互作用的相似性，并使用已知束能量的电子散射数据来测试能量重建方法和相互作用模型。我们发现，即使在简单的相互作用，没有π介子被检测到，只有一小部分的事件重建到正确的入射能量。更重要的是，广泛使用的相互作用模型再现重建的能量分布，只有定性和再现的质量变化强烈的光束能量。这表明了改进当前模型的必要性和途径，以满足下一代高精度实验的要求，如Hyper-Kamiokande（日本）和DUNE（美国）。
Neutrinos exist in one of three types or ‘flavours’—electron, muon and tau neutrinos—and oscillate from one flavour to another when propagating through space. This phenomena is one of the few that cannot be described using the standard model of particle physics (reviewed in ref. ), and so its experimental study can provide new insight into the nature of our Universe (reviewed in ref. ). Neutrinos oscillate as a function of their propagation distance (L) divided by their energy (E). Therefore, experiments extract oscillation parameters by measuring their energy distribution at different locations. As accelerator-based oscillation experiments cannot directly measureE, the interpretation of these experiments relies heavily on phenomenological models of neutrino–nucleus interactions to inferE. Here we exploit the similarity of electron–nucleus and neutrino–nucleus interactions, and use electron scattering data with known beam energies to test energy reconstruction methods and interaction models. We find that even in simple interactions where no pions are detected, only a small fraction of events reconstruct to the correct incident energy. More importantly, widely used interaction models reproduce the reconstructed energy distribution only qualitatively and the quality of the reproduction varies strongly with beam energy. This shows both the need and the pathway to improve current models to meet the requirements of next-generation, high-precision experiments such as Hyper-Kamiokande (Japan) and DUNE (USA).