ATMOSPHERIC NEUTRINOS AT SUPER-KAMIOKANDE AND PARAMETRIC RESONANCE IN NEUTRINO OSCILLATIONS
ATMOSPHERIC NEUTRINOS AT SUPER-KAMIOKANDE AND PARAMETRIC RESONANCE IN NEUTRINO OSCILLATIONS
复制标题
超级神冈德的大气中微子和中微子振荡中的参量共振
DOI：
10.1016/s0550-3213(98)00825-6
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
A. Smirnov
中科院分区：
文献类型：
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作者：
E. Akhmedov;Amol Dighe;P. Lipari;A. Smirnov
我们在具有 Δm2 层次结构的三中微子方案中考虑地球中大气中微子的振荡，并在以混合角 θ13 为特征的重质量本征态中添加少量电子中微子。我们发现，对于超级神冈数据和 sin22θ13⪅ 0.3 所示的 Δm2∼- (0.5−3) × 10−3eV2，多 GeV 中微子在次主导 νμ↔ θ3 模式中的振荡受到 MSW 和参量共振的增强。当中微子穿过地球核心时发生的参量共振占主导地位。对于 Δm2⋍ (1–2) × 10−3eV2，msin22θ13≲ 0.06 。即使对于较小的 θ13，共振物质效应也会导致可观察到的过量 e 类事件，并具有特定的天顶角依赖性。当 ∥ cos θe∥ > 0.2 时，多 GeV e 类事件的上下不对称性可达 15%，对于 ∥ cos θe∥ > 0.6 时，上下不对称性可达 30%，其中 θ 是电子的天顶角。共振物质效应与超级神冈数据的解释相关。
We consider the oscillations of atmospheric neutrinos in the earth in the three-neutrino scheme with a Δm2hierarchy and a small admixture of the electron neutrino in the heavy mass eigenstate characterized by the mixing angle θ13. We show that for Δm2∼- (0.5−3) × 10−3eV2indicated by the super-Kamiokande data and sin22θ13⪅ 0.3, the oscillations of multi-GeV neutrinos in the subdominant νμ↔ θ3mode are enhanced by the MSW and parametric resonances .The parametric resonance, which occurs when the neutrinos cross the core of the earth, dominates for Δm2⋍ (1–2) × 10−3eV2, msin22θ13≲ 0.06 . The resonance matter effects lead to an observable excess of the e-like events with a specifcic zenith angle dependence even for small θ13. The updown asymmetry of the multi-GeV e-like events can reach 15% for ∥ cos Θe∥ > 0.2 and up to 30% for ∥ cos Θe∥ > 0.6, where Θdis the zenith angle of the electron. The resonance matter effects are relevant for the interpretation of the super-Kamiokande data.