arXiv 1302.67732013-02hep-phhep-ex

$θ_{13}$大尺度中微子振荡物质效应的解析近似

Analytical Approximation of the Neutrino Oscillation Matter Effects at large $θ_{13}$

Sanjib Kumar Agarwalla, Yee Kao, Tatsu Takeuchi

备注：: 43 pages, 51 pdf figures. Uses jheppub.sty. Revised figs 5, 6, and 7
发表信息：: Journal of High Energy Physics 04 (2014) 047
DOI：: 10.1007/JHEP04(2014)047

摘要：

我们认为，中微子振荡的概率在物质中最好的理解，允许混合角和质量平方差的标准参数化“运行”的物质效应参数$a=2\sqrt{2}G_F N_e E$，其中$N_e$是物质中的电子密度和$E$是中微子的能量。我们提出了简单的分析近似这些“运行”参数。我们表明，对于中等大的值的$θ_{13}$，发现由反应堆实验，运行的混合角$θ_{23}$和CP违反阶段$δ$可以忽略不计。它大大简化了对所得振荡概率表达式的分析。试图直接提供物质中振荡概率的近似解析表达式的方法由于其依赖于$θ_{13}$中的展开而在准确性上受到影响，或者当包括$θ_{13}$中的高阶项时在简单性上受到影响。我们证明了我们的方法的准确性，通过比较它的精确数值结果，以及直接近似的Cervera等人，Akhmedov等人，浅野、水俣和弗罗因德。我们还讨论了我们的方法在计算出所需的基线长度和中微子能量的振荡概率表现出某些理想的功能的实用程序。

英文摘要：

We argue that the neutrino oscillation probabilities in matter are best understood by allowing the mixing angles and mass-squared differences in the standard parametrization to `run' with the matter effect parameter $a=2\sqrt{2}G_F N_e E$, where $N_e$ is the electron density in matter and $E$ is the neutrino energy. We present simple analytical approximations to these `running' parameters. We show that for the moderately large value of $θ_{13}$, as discovered by the reactor experiments, the running of the mixing angle $θ_{23}$ and the CP violating phase $δ$ can be neglected. It simplifies the analysis of the resulting expressions for the oscillation probabilities considerably. Approaches which attempt to directly provide approximate analytical expressions for the oscillation probabilities in matter suffer in accuracy due to their reliance on expansion in $θ_{13}$, or in simplicity when higher order terms in $θ_{13}$ are included. We demonstrate the accuracy of our method by comparing it to the exact numerical result, as well as the direct approximations of Cervera et al., Akhmedov et al., Asano and Minakata, and Freund. We also discuss the utility of our approach in figuring out the required baseline lengths and neutrino energies for the oscillation probabilities to exhibit certain desirable features.

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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