Long base-line neutrino experiments analyses.

长基线中微子实验分析。

• 批准号: ST/M000028/1
• 负责人: Jaroslaw Nowak
• 金额: $ 0.77万
• 依托单位: Lancaster University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FM000028%2F1
• 关键词: Long; base; line; neutrino; experiments

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.

中微子是宇宙中最丰富的基本粒子，但人们对它们的了解却最少。对中微子基本特征的测量将有助于更好地理解恒星、星系的演化，并可能部分解释为什么宇宙是由物质组成而明显缺乏反物质。已知中微子有三种类型：电子中微子、μ子中微子和τ中微子，它们总是相应地与电子、μ子或τ粒子成对产生。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，尽管中微子是与相关的变化的轻子一起产生的，但它们可以将其性质（振荡）从一种类型改变为另一种类型。中微子振荡被测量为一种类型的中微子的过量或/和另一种类型的中微子的不足。在 T2K 实验中，在日本东海岸的 J-PARC 加速器设施中产生了 μ 子中微子束（电子中微子污染约为 1%），并被引导至距离源头约 250 公里的西海岸的大型（50kton 纯水）探测器。在这个探测器中，我们计算μ子中微子中有多少部分转化为电子中微子，以及有多少部分在旅行中幸存下来。该测量的主要不确定性来自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，我们使用靠近中微子源放置的另一个探测器 (ND280) 来测量中微子束的成分。 ND280 是一款复杂的探测器，可以高精度测量中微子相互作用。我们建议测量中微子相互作用通道的横截面（相互作用发生的概率），其中产生两个中性介子和一个中性介子以及任何变化的介子。我们将测量带电电流（产生带电轻子）和中性电流相互作用（中微子在相互作用中幸存下来，但动量不同）。这些通道的精确测量将帮助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无法到达的。与其他基本粒子相比，中微子的质量非常小，但不为零。结果表明，只有左手中微子（其自旋投影与其动量方向相反）参与弱相互作用。然而，如果中微子具有磁矩，则可以通过将中微子变为右手中微子来交换光子（在环水平上）。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过量。利用来自 J-PARC 的高强度 μ 中微子束，将有可能测试低于当前 μ 中微子磁矩最佳极限的中微子磁矩值。该项目的另一部分是开始对未来的长基线实验（LBNE）进行分析。该实验将于 2023 年开始采集数据，建设将于 2017 年底开始。不合时宜的是，该实验具有测量 CP 破坏（物质和反物质粒子如何相互作用和衰变之间的差异）的能力。我们将参与目前正在美国芝加哥附近的费米国家实验室建造的35吨液氩原型探测器的数据分析。该分析将有助于了解探测器对宇宙射线的响应。除了分析之外，我们还将建造一个测试台来测试将放置在液态氩中的 LBNE 探测器的多个元件。

项目成果

Measurement of the neutrino-oxygen neutral-current interaction cross section by observing nuclear deexcitation ? rays

通过观察核去激发来测量中微子-氧中性流相互作用截面 ?

• DOI: 10.1103/physrevd.90.072012
• 发表时间: 2014
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Abe K

Measurement of the single p 0 production rate in neutral current neutrino interactions on water

水中中微子相互作用中单个p 0 产生率的测量

• DOI: 10.1103/physrevd.97.032002
• 发表时间: 2018
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Abe K

Upper bound on neutrino mass based on T2K neutrino timing measurements

• DOI: 10.1103/physrevd.93.012006
• 发表时间: 2015-02
• 期刊: Physical Review D
• 影响因子: 5
• 作者: T. Collaboration

First measurement of the ? µ charged-current cross section on a water target without pions in the final state

第一次测量？

• DOI: 10.1103/physrevd.97.012001
• 发表时间: 2018
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Abe K

Measurements of neutrino oscillation in appearance and disappearance channels by the T2K experiment with 6.6 × 1 0 20 protons on target

通过 T2K 实验对目标上的 6.6 × 1 0 20 质子进行的中微子振荡测量

• DOI: 10.1103/physrevd.91.072010
• 发表时间: 2015
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Abe K