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。测量中微子的基本特征将有助于更好地理解恒星、星系的演化，并可能解释为什么宇宙是由物质组成的，而明显缺乏反物质。已知的中微子有三种类型：电子中微子、μ子中微子和τ中微子，它们通常与电子、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，尽管中微子是由相关的变化轻子产生的，但它们可以从一种类型转变为另一种类型（振荡）。中微子振荡被测量为一种类型的中微子过量或/和另一种类型的中微子不足。在T2 K实验中，在日本东海岸的J-PARC加速器设施中产生了一束μ子中微子（约1%的电子中微子污染），并将其引导到距离源约250 km的西海岸的大型（50 kton纯水）远探测器。在这个探测器中，我们计算了有多少μ中微子转化为电子中微子，又有多少μ中微子在旅行过程中幸存下来。测量的主要不确定性来自于对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（ND 280）放置在中微子源附近，以测量中微子束的成分。ND 280是一种复杂的探测器，可以非常精确地测量中微子相互作用。我们建议测量横截面（发生相互作用的概率）的中微子相互作用通道与生产的两个中性π介子和一个中性π介子和任何改变π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，但动量不同）。对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，只有左手中微子（其自旋的投影方向与其动量方向相反）参与弱相互作用。然而，如果中微子具有磁矩，则有可能通过将中微子变为右手中微子来交换光子（在环路水平）。这种相互作用可以被探测为原子电子的弹性中微子相互作用的过量。随着J-PARC的μ子中微子束的高强度，将有可能测试μ子中微子磁矩低于当前最佳极限的中微子磁矩值。该项目的另一部分是开始分析未来的长基线实验（LBNE）。实验将于2023年开始获取数据，建设将于2017年底开始。不合时宜的是，这个实验有能力测量CP破坏（物质和反物质粒子相互作用和衰变的差异）。我们将参与美国芝加哥附近的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。分析将有助于了解探测器对宇宙射线的反应。除了分析，我们将建立一个测试台来测试LBNE探测器的几个元件，这些元件将被放置在液态氩中。

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