Atoms and small molecules interacting with strong external fields.

原子和小分子与强外部场相互作用。

• 批准号: RGPIN-2017-05655
• 负责人: Horbatsch, Marko
• 金额: $ 1.53万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=653839
• 关键词: Atoms; small; molecules; interacting; strong

The fundamental-physics part of the proposal aims for a more accurate determination of a fundamental constant and of properties of the proton, which most of the matter in the universe is made of. The fine-structure constant determines the strength of the coupling between charged particles, and also to photons, i.e., to light. It is known to nine digits to date, and has been determined by a number of methods in solid-state physics and in atomic spectroscopy. It needs to be known better for tests of the theory of electron-photon interactions, called quantum electrodynamics. While this is the most precisely known part of the standard model, there is a continuing push for more precise knowledge due to progress in atomic spectroscopy. ******The proton charge radius puzzle is of extreme importance in this context. Atomic hydrogen spectroscopy has hit a roadblock five years ago, since measurements on an artificial form of hydrogen (made in the laboratory), where the electron is replaced by a muon, has yielded a different radius value (0.84 femtometer), as opposed to 0.88 fm, as determined by a combination of regular hydrogen spectroscopic measurements. The muonic hydrogen determination is much more precise, since the heavier muon, as compared to the electron, is much closer to the proton on average, and therefore more sensitive. The large radius value of 0.88 fm had become the accepted value by the CODATA world group that is the caretaker of fundamental constants, since the most precise electron-proton scattering experiments of 2010 (from Mainz, Germany) also supported this value.******We have re-analyzed the Mainz data on e-p scattering, and found that they were not inconsistent with the small proton radius. Our re-analysis of the Mainz data relies on support from particle theory provided by a group in Spain. We also propose to also resolve a controversy between the magnetic charge radius value that currently exists between the Mainz and Jefferson Lab (USA) determinations. In related work we are modelling some of the regular hydrogen spectroscopy experiments (both past and a current one under way at York) to understand why the past one favoured a large charge radius value.******In the more applied area we are proposing to continue recent work on the water molecule, which is important in the context of radiation therapy. We will extend current work on strong-electric field ionization of H2O to intense laser field ionization with the aim to understand the properties of water under extreme conditions. This work extends our state-of-the-art work on collision-induced ionization and fragmentation which agrees well with experimental results.

该提案的基础物理部分旨在更准确地确定质子的基本常数和性质，宇宙中大多数物质都是由质子组成的。精细结构常数决定了带电粒子之间以及与光子之间的耦合强度，即，光。到目前为止，已知它是九位数，并且已经通过固态物理学和原子光谱学中的许多方法确定。为了检验电子-光子相互作用的理论，也就是量子电动力学，我们需要更好地了解它。虽然这是标准模型中已知最精确的部分，但由于原子光谱学的进步，人们一直在不断地推动更精确的知识。* *原子氢光谱在五年前遇到了障碍，因为对人工形式的氢（在实验室中制造）的测量，其中电子被μ子取代，产生了不同的半径值（0.84 femmeter），而不是0.88 fm，这是由常规氢光谱测量的组合确定的。μ介子氢的测定要精确得多，因为与电子相比，较重的μ介子平均更接近质子，因此更灵敏。0.88 fm的大半径值已经成为CODATA世界组的接受值，该世界组是基本常数的管理者，因为2010年最精确的电子-质子散射实验（来自德国美因茨）也支持这个值。我们重新分析了美因茨的e-p散射数据，发现它们与小质子半径并不矛盾。我们对美因茨数据的重新分析依赖于西班牙一个小组提供的粒子理论的支持。我们还建议解决美因茨和杰斐逊实验室（美国）测定之间目前存在的磁荷半径值之间的争议。在相关的工作中，我们正在模拟一些常规的氢光谱实验（包括过去和约克正在进行的实验），以理解为什么过去的实验倾向于大的电荷半径值。在更多的应用领域，我们建议继续最近的工作，水分子，这是重要的背景下，放射治疗。我们将把目前对H2O的强电场电离的工作扩展到强激光场电离，目的是了解极端条件下水的性质。这项工作扩展了我们在碰撞诱导电离和碎裂方面的最新工作，与实验结果吻合得很好。