First Results on the Search for Neutrinoless Double Beta Decay from the SNO+ Experiment

SNO 实验中寻找无中微子双贝塔衰变的初步结果

• 批准号: 1793321
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-1793321
• 关键词: First; Results; Search; Neutrinoless; Double

Some of the most exciting physics to emerge over the last decade has been in the field of neutrino physics. One of the forefront experiments here has been the Sudbury Neutrino Observatory (SNO), based in the SNOLAB underground scientific laboratory in Sudbury, Ontario (Canada), which was a recipient of the 2015 Nobel Prize in physics. The SNO group at Oxford have played a leading role in solving the "Solar Neutrino Problem" and clearly demonstrating, for the first time, that neutrinos exists as mixed states which allow them to apparently "oscillate" from one type to another. On the heels of this tremendously successful project, a follow-on experiment, SNO+, is being pursued with a remarkably diverse and interesting range of physics objectives. The main objective of this project is to sensitively search for a very rare process called "neutrinoless double beta decay." An observation of this would both permit a determination of the absolute neutrino masses and would establish that neutrinos act as their own antiparticles, which could have significant consequences for our understanding of the matter/antimatter asymmetry in the universe. This area of study is considered to be of extremely high importance in particle physics and the Oxford group has played a fundamental role in establishing the technique that will be used for this search. In addition, other physics goals include studies of low energy solar neutrinos, oscillations of reactor antineutrinos, searches for non-standard modes of nucleon decay, study of geo-neutrinos generated from within the earth, and to act as an important detector for neutrinos from galactic supernovae. The incoming student will work closely with the Oxford SNO+ group, which currently consists of 3 academics, 1 postdoctoral researcher and 3 other PhD students and is part of a larger UK effort, which includes 5 additional institutions: University of Sussex, University of Liverpool, QMUL, University of Sheffield and University of Lancaster. The UK SNO+ collaborators comprise ~30% of the collaboration and fill many key positions within the project to which the student will also contribute. The head of the Oxford group, Steve Biller, is the UK spokesperson and leads the development effort on tellurium loading techniques in scintillator for neutrinoless double beta decay 0nbb, where Oxford has made significant contributions and the thesis project will involve an extension of this work. The UK groups jointly have responsibility for delivering one of the major calibration systems for the experiment, the Oxford portion of which focuses on in situ measurements of optical scattering within the detector, and the student's work will also involve analysis related to this system. The main physics effort for the thesis will focus on producing the first results on neutrinoless double beta decay. The detector is currently undergoing initial water fill and commissioning. Liquid scintillator will be introduced in 2017 and isotope for neutrinoless double beta decay will be introduced in early 2018. The incoming PhD student will participate in development, simulation, calibration, operation, analysis and the production of first results.

过去十年中出现的一些最令人兴奋的物理学属于中微子物理学领域。这里最前沿的实验之一是萨德伯里中微子观测站 (SNO)，位于加拿大安大略省萨德伯里的 SNOLAB 地下科学实验室，该实验室荣获 2015 年诺贝尔物理学奖。牛津大学的 SNO 小组在解决“太阳中微子问题”方面发挥了主导作用，并首次清楚地证明中微子以混合态存在，这使它们能够明显地从一种类型“振荡”到另一种类型。继这个非常成功的项目之后，后续实验 SNO+ 正在开展，其物理目标范围非常多样化和有趣。该项目的主要目标是灵敏地寻找一种非常罕见的过程，称为“无中微子双贝塔衰变”。对此的观察既可以确定中微子的绝对质量，也可以确定中微子充当它们自己的反粒子，这可能对我们理解宇宙中物质/反物质不对称性产生重大影响。这一研究领域被认为在粒子物理学中极其重要，牛津小组在建立用于该研究的技术方面发挥了基础作用。此外，其他物理目标包括研究低能太阳中微子、反应堆反中微子的振荡、寻找核子衰变的非标准模式、研究地球内部产生的地中微子，以及充当银河超新星中微子的重要探测器。即将入学的学生将与牛津 SNO+ 小组密切合作，该小组目前由 3 名学者、1 名博士后研究员和 3 名其他博士生组成，是英国更大努力的一部分，其中包括另外 5 所机构：苏塞克斯大学、利物浦大学、QMUL、谢菲尔德大学和兰卡斯特大学。英国 SNO+ 合作者占合作的约 30%，并填补了学生也将参与的项目中的许多关键职位。牛津小组的负责人 Steve Biller 是英国发言人，领导无中微子双 β 衰变 0nbb 闪烁体碲装载技术的开发工作，牛津大学在这方面做出了重大贡献，论文项目将涉及这项工作的扩展。英国小组共同负责为该实验提供主要校准系统之一，其中牛津部分重点关注探测器内光学散射的原位测量，学生的工作还将涉及与该系统相关的分析。本论文的主要物理工作将集中于产生无中微子双贝塔衰变的第一个结果。该探测器目前正在进行初始注水和调试。液体闪烁体将于 2017 年推出，无中微子双 β 衰变同位素将于 2018 年初推出。即将入学的博士生将参与开发、模拟、校准、操作、分析和第一个结果的产生。