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arXiv 1504.06283hep-ph
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中微子振荡参数简并性的新认识及其T2K、NO $ν$ A和ICAL的分辨

New look at the degeneracies in the neutrino oscillation parameters, and their resolution by T2K, NO$ν$A and ICAL

Monojit Ghosh, Pomita Ghoshal, Srubabati Goswami, Newton Nath, Sushant K. Raut

摘要:

目前,中微子振荡参数的三个主要未知数是质量等级、$θ_{23}$的八分圆和CP相$δ_{CP}$。众所周知,层级$-δ_{CP}$和八分体简并的存在影响这些参数的明确测定。在本文中,我们表明,一个全面的方法来研究剩余的参数退化的形式是一个广义的层次- $θ_{23}$ - $δ_{CP}$退化。我们发现,错误的层次结构和/或错误的八分体的解决方案可以进一步分为八个不同的解决方案,这取决于它们是否发生错误或正确的值的$δ_{CP}$。这八个解不同于原来的八重退化解,并且原则上即使已知$θ_{13}$也可以存在。这些多个解除了影响真实层次和八分圆的确定之外,还影响$δ_{CP}$的准确估计。我们确定这八个不同的简并解决方案可以发生在测试($θ_{23} - δ_{CP}$)参数空间,以长基线实验NO $ν$ A运行在中微子模式为例。包含NO $ν$ A antineutrino运行消除了出现正确和错误层次结构的错误八分体解决方案。向其中添加T2 K数据可以在很大程度上解决错误的层次结构--正确的八分圆解决方案。通过结合NO $ν$ A + T2 K和大气中微子数据,可以消除剩余的错误的层次解决方案。我们使用ICAL@INO作为原型大气中微子探测器来证明这一点。我们发现,退化可以解决在$2σ$水平的组合数据集,在研究中考虑的真正的参数空间。

英文摘要:

At present the three major unknowns in neutrino oscillation parameters are the mass hierarchy, the octant of $θ_{23}$ and the CP phase $δ_{CP}$. It is well known that the presence of hierarchy$-δ_{CP}$ and octant degeneracies affects the unambiguous determination of these parameters. In this paper we show that a comprehensive way to study the remaining parameter degeneracies is in the form of a generalized hierarchy-$θ_{23}$ - $δ_{CP}$ degeneracy. We show that the wrong-hierarchy and/or wrong-octant solutions can be further classified into eight different solutions depending on whether they occur with the wrong or right value of $δ_{CP}$. These eight solutions are different from the original eightfold degenerate solutions and can exist, in principle, even if $θ_{13}$ is known. These multiple solutions, apart from affecting the determination of the true hierarchy and octant, also affect the accurate estimation of $δ_{CP}$. We identify which of these eight different degenerate solutions can occur in the test ($θ_{23} - δ_{CP}$) parameter space, taking the long-baseline experiment NO$ν$A running in the neutrino mode as an example. The inclusion of the NO$ν$A antineutrino run removes the wrong-octant solutions appearing with both right and wrong hierarchy. Adding T2K data to this resolves the wrong hierarchy -- right octant solutions to a large extent. The remaining wrong hierarchy solutions can be removed by combining NO$ν$A + T2K with atmospheric neutrino data. We demonstrate this using ICAL@INO as the prototype atmospheric neutrino detector. We find that the degeneracies can be resolved at the $2σ$ level by the combined data set, for the true parameter space considered in the study.

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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