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arXiv 0810.2679hep-ph
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物质中中微子振荡的精确解析描述

An accurate analytic description of neutrino oscillations in matter

E. Kh. Akhmedov, Viviana Niro

摘要:

本文导出了任意密度分布物质中双味中微子振荡几率的一个简单的封闭形式的解析表达式。我们的公式是基于微扰展开,并允许一个简单的计算高阶修正。当密度沿中微子路径变化相对缓慢和/或中微子能量不是很接近Mikheyev-Smirnov-Wolfenstein(MSW)共振能量时,膨胀参数很小。我们的近似不等价于绝热近似,而是超越了绝热近似,我们用几个模型的密度剖面(包括地球的PREM密度剖面)证明了我们结果的正确性。它表明,通过结合从有效的MSW共振以下和以上的扩展得到的结果,可以得到一个很好的描述中微子振荡的物质在整个能量范围内,包括共振区。

英文摘要:

A simple closed-form analytic expression for the probability of two-flavour neutrino oscillations in a matter with an arbitrary density profile is derived. Our formula is based on a perturbative expansion and allows an easy calculation of higher order corrections. The expansion parameter is small when the density changes relatively slowly along the neutrino path and/or neutrino energy is not very close to the Mikheyev-Smirnov-Wolfenstein (MSW) resonance energy. Our approximation is not equivalent to the adiabatic approximation and actually goes beyond it. We demonstrate the validity of our results using a few model density profiles, including the PREM density profile of the Earth. It is shown that by combining the results obtained from the expansions valid below and above the MSW resonance one can obtain a very good description of neutrino oscillations in matter in the entire energy range, including the resonance region.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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