Seed Corn Funding for Braidwood Project

布雷德伍德项目玉米种子资金

• 批准号: PP/D006848/1
• 负责人: Steven Biller
• 金额: $ 4.38万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=PP%2FD006848%2F1
• 关键词: Seed; Corn; Funding; Braidwood; Project

Neutrinos are governed by the weak nuclear force and form part of that fundamental class of particles called leptons. They come in three 'flavours' which are each paired with the electron, muon and tauon particles, respectively. We now know, however, that this classification is not as simple as it seems. Neutrinos also have mass (previously thought to be zero), but these masses do not directly correspond to those of the three neutrino flavours. Instead, a neutrino of a given flavour (like the electron-neutrino) can be viewed as a mixture of different neutrino mass states. This property allows neutrinos to apparently change or 'oscillate' between different types. A similar mixing phenomenon has long been known to exist among the quarks, though, at first glance, through a somewhat different mechanism. One of the many surprises is that the mixing amongst neutrinos is much larger than amongst the quarks. Nevertheless, theorists hope that the mixings in the two classes of particles can yet be related through some 'Grand Unified Theory' that brings together quarks and leptons, though the ability to do this straightforwardly will hinge on the value of a final mixing parameter which has not yet been determined. This parameter is known as 'theta13.' The oscillation relevant to theta13 may be affected as the neutrino state passes through matter and, if this were observed, it could be used to resolve the ordering of the neutrino mass states. Furthermore, it turns out that a third mixing angle would also allow some particle and anti-particle interactions to proceed at slightly different rates giving rise to 'CP-violation,' as for quarks. If the effect for leptons is large enough, it might explain the very existence of all the matter we see today. Therefore, the measurement of this third mixing angle and any associated CP-violation is an important next step. The first priority is to make a precise measurement of theta13, independent of these other possible effects. This is of fundamental interest in itself, and would also then allow other experiments (such as the planned T2K and NOvA projects) to look for CP violation and matter effects in the most sensitive and unambiguous manner. One of the best approaches to doing this is by looking for the apparent disappearance of anti-electron-neutrinos, produced in a nuclear reactor (due to their oscillations). Based on current experimental data, the distance scale over which this theta13 oscillation should occur is just under 2 kilometres from the reactor core. The challenge is that the size of the effect is expected to be only about 1 percent of the total, detectable neutrino flux - requiring a level of detection unprecedented for neutrino experiments. It is this measurement which the Braidwood project intends to carry out.

中微子由弱核力量支配，并形成了该基本类别颗粒的一部分，称为瘦素。它们分别有三种“口味”，分别与电子，哑光和陶恩颗粒配对。但是，我们现在知道，这种分类并不像看起来那样简单。中微子也具有质量（以前认为为零），但是这些质量并不直接与三种中微子风味的质量相对应。取而代之的是，可以将给定风味的中微子（如电子中间人）视为不同中微子质量状态的混合物。该特性允许中微子在不同类型之间显然改变或“振荡”。然而，长期以来，已经知道在夸克之间存在类似的混合现象，但乍一看，通过一种不同的机制存在。众多惊喜之一是中微子之间的混合比夸克中的混合要大得多。然而，理论家希望这两类粒子中的混合可以通过一些“宏伟的统一理论”汇集在一起​​，这些理论可以将夸克和瘦素融合在一起，尽管直接做到这一点的能力将取决于尚未确定的最终混合参数的价值。该参数称为“ theta13”。随着中微子状态通过物质，与Theta13相关的振荡可能会受到影响，如果观察到这一点，则可以用来解决中微子质量状态的排序。此外，事实证明，第三个混合角还将允许某些粒子和抗粒子相互作用以略有不同的速率进行，从而导致“ CP侵略”，以至于夸克。如果对瘦素的影响足够大，它可能会解释我们今天看到的所有问题的存在。因此，测量第三个混合角度和任何相关的CP侵入是重要的下一步。首要任务是对theta13进行精确测量，而与这些可能的其他可能影响无关。这本身就是基本的兴趣，然后还将允许其他实验（例如计划的T2K和NOVA项目）以最敏感和明确的方式寻找CP违规和物质效应。做到这一点的最好方法之一是寻找在核反应堆中产生的抗电子中的明显消失（由于它们的振荡）。基于当前的实验数据，该THETA13振荡的距离尺度距离反应堆核心不到2公里。面临的挑战是，效应的大小预计仅是可检测到的中微子通量的1％，这需要用于中微子实验的前所未有的检测水平。 Braidwood项目打算进行这项测量。