Title: Implications of partially degenerate neutrinos at a high scale in the light of KamLAND and WMAP Show Chinese title

Title: 部分简并中微子在高能标下的含义：基于KamLAND和WMAP的视角

Abstract: Electroweak radiative corrections can generate the neutrino (mass)$^2$ difference required for the large mixing angle solution (LMA) to the solar neutrino problem if two of the neutrinos are assumed degenerate at high energy. We test this possibility with the existing experimental knowledge of the low energy neutrino mass and mixing parameters. We derive restrictions on ranges of the high scale mixing matrix elements and obtain predictions for the low energy parameters required in order to get the LMA solution of the solar neutrino problem picked out by KamLAND. We find that in the case of standard model this is achieved only when the (degenerate) neutrino masses lie in the range $(0.7-2) \eV$ which is at odds with the cosmological limit $m_{\nu}<0.23 \eV$ (at $95 % C.L$) established recently using WMAP results. Thus SM radiative corrections cannot easily generate the LMA solution in this scenario. However, the LMA solution is possible in case of the MSSM electroweak corrections with (almost) degenerate spectrum or with inverted mass hierarchy for limited ranges in the high scale parameters. Show Chinese abstract

Abstract: 电弱辐射修正可以在高能下假设两个中微子简并的情况下，产生解决太阳中微子问题的大混合角解（LMA）所需的中微子（质量）$^2$差异。 我们利用现有的低能中微子质量和混合参数的实验知识来检验这种可能性。 我们推导出高能尺度混合矩阵元素的范围限制，并得到为了通过KamLAND选出太阳中微子问题的LMA解所需的低能参数预测。 我们发现，在标准模型的情况下，只有当中微子质量位于范围$(0.7-2) \eV$时才能实现这一点，这与最近利用WMAP结果建立的宇宙学限制$m_{\nu}<0.23 \eV$（在$95 % C.L$处）相矛盾。 因此，在这种情况下，标准模型的辐射修正无法轻易生成LMA解。 然而，在MSSM电弱修正的情况下，对于高能参数的有限范围内，如果具有（几乎）简并谱或倒置质量层次，则LMA解是可能的。