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Physics of Lepton Flavor Mixing

轻子风味混合的物理原理

基本信息

批准号：
09640370
负责人：
MINAKATA Hisakazu
金额：
$ 0.7万
依托单位：
TOKYO METROPOLITAN UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640370/
关键词：
Neutrino mass Flavor mixing 3 generation leptons CP violation Dark matter long-baseline neutrino experiment Majorana neutrino Double beta decay 三世代ニュートリノシーソー機構シ-ソ-機構バリオン数非対称性

项目摘要

During the research term 1997-98 I concentrated on two topics, (1) CP Violation in the Lepton Sector, and (2) Dark Matter Neutrino Hypothesis ; experimental constraints and how to test it.(1) I, in collaboration with Hiroshi Nunokawa (Univ.de Campinas, Brazil), studied the problem of how to measure leptonic CP violation in long-baseline neutrino oscillation experiments. There exists a notorious problem in such measurement ; it is the problem of the matter effect pollusion. That is, the genuine CP violation effect due to the leptonic Kobayashi-Maskawa phase could be masked by that due to matter effect in the IEarth. We have presented a formalism based on matter effect peturbation theory by which one can obtain bird-eye view of the interplay between these two effects. It will enable us to select out the most feasible channel of the experiment searching for the genuine phase CP violation. Moreover, we have proposed a new strategy for sensitive detection of CP violation by setting up an intermediate detector in a dedicated long-baseline experimennt.(2) The neutrino dark matter hypothesis has been topics of interests as an interesting possibility of explaining structure formation in a consistent way with COBE data. I, in collaboration with Osamu Yasuda (TMU), demonstrated that there exist severe constraints on that hypothesis in the standard three-flavor mixing scheme due to the solar and the atmospheric neutrino observation as well as the reactor and accelerator data. We have shown with constraints imposed by CHOOZ reactor experiment that the dark matter neutrinos must have an almost degenerate mass spectrum. Furthermore, we have shown that if neutrinos are Majorana particles this possibility will be severely tested within 5 years by the coming new double beta decay experiment.

在1997-98年的研究期间，我专注于两个主题，(1)轻子区的CP破坏，(2)暗物质中微子假说，实验约束和如何检验它。(1)我与巴西坎皮纳斯大学的Hiroshi Nunokawa合作，研究了如何在长基线中微子振荡实验中测量轻子CP破坏的问题。在这种测量中存在一个臭名昭著的问题，那就是物质效应污染问题。也就是说，由轻子小林-Maskawa相引起的真正的CP破坏效应可以被IEarth中的物质效应所掩盖。我们提出了一种基于物质效应颤动理论的形式主义，通过它可以鸟瞰这两种效应之间的相互作用。这将使我们能够选择出寻找真正的CP破坏的实验中最可行的通道。此外，我们还提出了一种通过在专门的长基线实验中设置中间探测器来灵敏探测CP破坏的新策略。(2)中微子暗物质假说一直是人们感兴趣的话题，因为它是一种有趣的可能性，可以用COBE数据来解释结构的形成。我与Osamu Yasuda(TMU)合作，证明了由于太阳和大气中微子的观测以及反应堆和加速器的数据，在标准的三味混合方案中存在对这一假设的严格限制。我们已经证明，在Chooz反应堆实验的约束下，暗物质中微子一定有一个几乎简并的质谱图。此外，我们已经证明，如果中微子是马约拉纳粒子，这种可能性将在5年内通过即将到来的新的双β衰变实验得到严格测试。