Long base-line neutrino experiments analyses.

中微子是宇宙中最丰富的基本粒子，但人们对它们的了解最少。测量中微子的基本特征将有助于更好地理解恒星和星系的演化，并可能部分解释为什么宇宙是由明显缺乏反物质的物质组成的。已知的中微子有三种类型：电子中微子、介子中微子和τ中微子，它们总是与电子、μ子或τ粒子相应成对产生。中微子和它们的伙伴被称为轻子。在过去的几十年里，许多实验表明，尽管产生中微子时伴随有变化的轻子，但它们可以改变性质（振荡），从一种类型转变为另一种类型。中微子振荡被测量为一种类型的中微子过剩或/和另一种类型的亏缺。在T2K实验中，在日本东部的J-PARC加速器设施中产生了一束介子中微子（带有大约1%的电子中微子污染），并将其引导到距离源约250公里的西海岸的一个大型（50万吨纯水）远探测器上。在这个探测器中，我们计算了介子中微子中有多少转化为电子中微子，又有多少在旅行中幸存下来。该测量的主要不确定度来自于电子-中微子相互作用中产生的电子的错误识别。为了更好地了解背景，我们使用另一个探测器（ND280）放置在中微子源附近，以测量中微子束的组成。ND280是一种复杂的探测器，可以高精度地测量中微子相互作用。我们建议测量产生两个中性介子和一个中性介子以及任何改变的介子的中微子相互作用通道的截面（相互作用发生的概率）。我们将测量带电电流（带电轻子的产生）和中性电流相互作用（中微子在相互作用中幸存，但动量不同）。这些通道的精确测量将有助于我们更好地理解质子和中子结构的轴向部分，这是电子在核子上的散射所不能达到的。与其他基本粒子相比，中微子的质量非常小，但它不是零。结果表明，只有左旋中微子（其自旋的投射方向与动量方向相反）参与弱相互作用。然而，如果中微子具有磁矩，则有可能将光子（在环路水平上）与中微子交换为右手态光子。这种相互作用可以被检测为原子电子的弹性中微子相互作用的过剩。利用来自J-PARC的高强度μ子中微子束，将有可能测试低于当前最佳μ子中微子磁矩限制的中微子磁矩值。该项目的另一部分是开始为未来的长基线实验（LBNE）进行分析。实验将于2023年开始采集数据，并将于2017年底开始建设。这个实验有能力测量CP违逆（物质和反物质粒子相互作用和衰变之间的差异）。我们将参与美国芝加哥附近费米国家实验室正在建造的35吨液态氩原型探测器的数据分析。这一分析将有助于理解探测器对宇宙射线的反应。除了分析之外，我们还将建立一个测试台来测试LBNE探测器的几个元件，这些元件将放置在液态氩气中。

The neutrinos are most abound elementary particles in the Universe yet they are least understood. Measurement of basic features of neutrinos will allow better understanding of evolution of starts, galaxies and might be part of the explanation why the Universe is made of matter with apparent lack of anti-matter. There are three know types of neutrinos: electron neutrino, muon neutrino and tau neutrino and they are always produce in pair with electron, muon or tau particle correspondently. Neutrino and their partners are called leptons. For a last few decades many experiments showed that although neutrinos are produced with associated changed lepton they can change their nature (oscillate) from one type to another. Neutrino oscillations are measured as an excess of one type of neutrinos or/and a deficit of another type. In the T2K experiment a beam on muon neutrinos (with about 1% contamination of electron neutrinos) are created at J-PARC accelerator facility on the east cost of Japan and directed to a large (50kton pure water) far detector on the west coast about 250 km from the source. In this detector we count what fraction on muon neutrinos was transform to electron neutrino and what fraction survive the travel. The main uncertainties for that measurement come from the mis-identification of electron produced in the electron neutrino interaction. To better understand the background we use another detector (ND280) placed close to the source of neutrinos to measure composition of the neutrino beam. The ND280 is complex detector which can measure neutrino interactions with great precision. We propose to measure cross sections (probability that interaction occurs) for neutrino interaction channels with production of two neutral pions and one neutral pion and any changed pion. We will measure both charged current (with production of charged lepton) and neutral current interactions (with neutrino surviving the interactions but with different momentum). The precise measurement of those channels will help us better understand the axial part of the proton and neutron structure, which is not accessible by scattering of electron on nucleons. Neutrinos masses are very small when compared to other elementary particles but it is not zero. It was shown that only left-handed neutrinos (projection of their spin is opposite to the direction of their momentum) take part in the weak interactions. However if neutrinos have magnetic moment it is possible to exchange a photon (at a loop level) with change of neutrino into a right-handed one. Such interaction can be detected as an excess of elastic neutrino interactions of the atomic electrons. With a high intensity of the muon neutrino beam from the J-PARC it will be possible to test values of the neutrino magnetic moment below current best limit on muon neutrino magnetic moment. Another part of the project is to start analyses for the future Long Base-Line Experiment (LBNE). The experiment will start taking data in 2023 and the construction will start at the end of 2017. Untimely this experiment has a capability to measure CP violation (difference between how matter and anti-matter particles interact and decay). We will participate in the data analysis of the 35 ton of Liquid Argon prototype detector which is currently under construction at Fermi National Laboratory close to Chicago, US. The analysis will help to understand detector response to cosmic rays. In addition to the analysis we will build a test stand to test several elements of the LBNE detectors which will be place in the liquid Argon.