AI 中文总结
以橡树岭国家实验室散裂中子源为例，研究其对MeV-GeV质量范围重中性轻子的敏感性。考虑HNL在π介子和μ子衰变中产生及衰变情况，分析COHERENT探测器敏感性。发现现有探测器能设限制，未来吨级探测器可探测新区域，为新物理搜索提供互补途径。
AI 中文摘要
散裂中子源通过静止π介子和μ子衰变提供强中微子通量，能量在几十MeV范围内。像COHERENT这样的实验利用这些通量通过相干弹性中微子-原子核散射（CEνNS）探测中微子。然而，这些设施也为产生和探测轻的、隐蔽的或弱耦合粒子提供了独特机会。本文以橡树岭国家实验室的散裂中子源为例，研究其对MeV-GeV质量范围内重中性轻子（HNLs）的敏感性。考虑了静止π介子和μ子衰变中HNL的产生，以及它们在探测器体积内衰变成可见标准模型粒子的情况。分析了一系列当前和提议的COHERENT探测器，并评估了它们对HNL与μ子和电子中微子混合以及混合混合情景的敏感性。发现现有探测器能设置有意义的限制，特别是对μ子味混合，而未来吨级探测器可探测参数空间中以前未探索的区域。还讨论了其他相关散裂源设施的前景及其预计敏感性的互补性。结果表明，散裂中子源处的CEνNS实验除作为中微子探测器的主要作用外，还为新物理搜索提供了有力的互补途径。
英文摘要
Spallation neutron sources provide intense neutrino fluxes from pion and muon decay at rest, with energies in the few tens of MeV range. Experiments such as COHERENT exploit these fluxes to detect neutrinos via coherent elastic neutrino$\unicode{x2013}$nucleus scattering (CE$ν$NS). However, these facilities also offer a unique opportunity to produce and probe light, secluded, or weakly$\unicode{x2013}$coupled particles. In this work, we investigate the sensitivity of the Spallation Neutron Source at the Oak Ridge National Laboratory to heavy neutral leptons (HNLs) in the MeV$\unicode{x2013}$GeV mass range, as a case study. We consider HNL production in pion and muon decays at rest, followed by their decay into visible Standard Model particles within the detector volume. We analyze a range of current and proposed COHERENT detectors and evaluate their sensitivity to HNL mixing with muon and electron neutrinos, as well as to scenarios with mixed mixing. We find that existing detectors can set meaningful constraints, particularly for muon$\unicode{x2013}$flavor mixing, while future ton$\unicode{x2013}$scale realizations can probe previously unexplored regions of the parameter space. We further discuss prospects at other relevant spallation source facilities and comment on the complementarity of their projected sensitivities. Our results demonstrate that CE$ν$NS experiments at spallation neutron sources provide a powerful, complementary avenue for new physics searches beyond their primary role as neutrino detectors.
Comments17 pages, 7 figures
