Solar neutrinos can be efficiently upscattered to MeV-scale heavy neutral leptons (HNLs) within the Earth’s mantle. HNLs can then decay to electron-positron pairs leading to energy deposition inside large volume detectors. In this paper, we consider mass-portal upscattering of solar neutrinos to HNLs of mass $20\mathrm{MeV}\ge m_N\ge 2m_e$. The large volume of the Earth compensates for the long decay length of the HNLs leading to observable rates of $N\to {\nu }_{\alpha }{e}^{+}{e}^{-}$ in large volume detectors. We find that searches for mantle-upscattered HNLs can set novel limits on mixing with third-generation leptons, $|U_{\tau N}|$ for masses in the MeV regime; sensitivity to mixing with first- and second-generation leptons is not competitive with existing search strategies.

中文翻译：

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发光的太阳中微子。二、大规模混合门户

太阳中微子可以有效地向上散射到地幔内的 MeV 级重中性轻子 (HNL)。然后 HNL 可以衰变成正负电子对，从而导致大体积探测器内的能量沉积。在本文中，我们考虑了太阳中微子的质量入口向上散射到质量为$20\mathrm{电动汽车}\ge {米}_N\ge 2{米}_{\mathrm{电子}}$. 地球的大体积补偿了 HNL 的长衰减长度，导致可观察到的速率$N\to {\nu }_{\alpha }{\mathrm{电子}}^{+}{\mathrm{电子}}^{-}$在大容量探测器中。我们发现寻找地幔上散射的 HNL 可以为与第三代轻子的混合设置新的限制，$|{你}_{\tau N}|$对于 MeV 体制中的群众；与第一代和第二代轻子混合的敏感性与现有的搜索策略没有竞争力。