One of the most puzzling questions in neutrino physics is the origin of the excess at 5?MeV in the reactor antineutrino spectrum. In this paper, we explore the excess via the reaction C 13 ( ν ˉ , ν ˉ ′ n ) C 12 ( * ) in organic scintillator detectors. The deexcitation of C 12 ( * ) yields a prompt 4.4?MeV photon, while the thermalization of the product neutron causes proton recoils, which in turn yield an additional prompt energy contribution with finite width. Together, these effects can mimic an inverse beta decay event with around 5?MeV energy. We consider several nonstandard neutrino interactions to produce such a process and find that the parameter space preferred by Daya Bay is disfavored by measurements of neutrino-induced deuteron disintegration and coherent elastic neutrino-nucleus scattering. While nonminimal particle physics scenarios may be viable, a nuclear physics solution to this anomaly appears more appealing.
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机译：中微子物理学中最令人困惑的问题之一是反应堆抗中微子谱中5？MeV处过量的起源。在本文中，我们通过有机闪烁体检测器中的反应C 13（νˉ，νˉ'n）C 12（*）探索了过量元素。 C 12（*）的去激励产生迅速的4.4？MeV光子，而产物中子的热化引起质子反冲，反过来又产生有限宽度的快速能量贡献。这些效应加在一起可以模拟5？MeV左右能量的反向β衰变事件。我们考虑了几种非标准的中微子相互作用来产生这样的过程，发现通过测量中微子引起的氘核崩解和相干的弹性中微子-核散射，不利于大亚湾的参数空间。虽然非最小粒子物理方案可能是可行的，但针对此异常的核物理解决方案似乎更具吸引力。
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