Neutrino flavor ratios as diagnostic of solar WIMP annihilation
Neutrino flavor ratios as diagnostic of solar WIMP annihilation
复制标题
中微子风味比作为太阳 WIMP 湮灭的诊断
DOI：
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发表时间：
2007
期刊：
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通讯作者：
T. Weiler
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作者：
R. Lehnert;T. Weiler
我们认为中微子（和反中微子）的味道到达地球的中微子产生的湮灭弱相互作用的大质量粒子（WIMP）在太阳的核心。利用密度矩阵理论研究了太阳物质对产生的≥ GeV中微子味传播的影响。物质效应，包括质量态能级交叉，影响的味道通量相当大。这里的阐述有点教育性，因为它从太阳中心的单一味道的绝热演化开始，θ 13设置为零，并进展到从太阳核心到地球的WIMP衰变中预期的味道比率的完全现实的处理。在完全真实的计算中，包括非绝热能级交叉，θ 13和CP破坏相δ的可能非零值。由于物质的共振增强，θ 13的非零值甚至小于一度也会显著影响风味传播。正常和倒置的中微子质量层次被认为是。我们的主要结论是，测量≥ GeV太阳中微子的味比（除了能谱）可以提供WIMP模型之间的区别。特别是，我们证明了来自两种主要WIMP终态的中微子在地球上的味道差异，即W + W和95% bb + 5% τ + τ。相反，如果未来的加速器能从产生中学习到WIMP的性质，那么≥ GeV太阳中微子的味比可能有助于推断θ 13和质量等级。通过全面计算，我们发现（并证明了）一些一般特征：在太阳核心产生的一个偏味流到达地球时仍然是偏味流，对于最大θ 32但任意θ 21和θ 13，置换δ → π ― δ使ν e味谱不变，但在地球处使ν μ和ν τ谱互换;只有反中微子和反中微子对混合相δ的依赖性不被抑制到δ m221/δ m232量级。
We consider the neutrino (and antineutrino) flavors arriving at the Earth for neutrinos produced in the annihilation of weakly interacting massive particles (WIMPs) in the sun's core. Solar-matter effects on the flavor propagation of the resulting ≥ GeV neutrinos are studied analytically within a density-matrix formalism. Matter effects, including mass-state level crossings, influence the flavor fluxes considerably. The exposition herein is somewhat pedagogical, in that it starts with adiabatic evolution of single flavors from the sun's center, with θ 13 set to zero, and progresses to fully realistic processing of the flavor ratios expected in WIMP decay, from the sun's core to the Earth. In the fully realistic calculation, nonadiabatic level crossing is included, as are possible nonzero values for θ 13 and the CP-violating phase δ. Because of resonance enhancement in matter, nonzero values of θ 13 even smaller than a degree can noticeably affect flavor propagation. Both normal and inverted neutrino-mass hierarchies are considered. Our main conclusion is that measuring flavor ratios (in addition to energy spectra) of ≥ GeV solar neutrinos can provide discrimination between WIMP models. In particular, we demonstrate the flavor differences at the Earth for neutrinos from the two main classes of WIMP final states, namely W + W ― and 95% bb + 5% τ + τ ― . Conversely, if WIMP properties were to be learned from production in future accelerators, then the flavor ratios of ≥ GeV solar neutrinos might be useful for inferring θ 13 and the mass hierarchy. From the full calculations, we find (and prove) some general features: a flavor-democratic flux produced at the sun's core arrives at the Earth still flavor democratic; for maximal θ 32 but arbitrary θ 21 and θ 13 , the replacement δ → π ― δ leaves the ν e flavor spectra unaltered but interchanges ν μ and ν τ spectra at the Earth; and, only for neutrinos in the inverted hierarchy and antineutrinos in the normal hierarchy is the dependence on the mixing phase δ not suppressed to order δm 2 21 /δm 2 32 .