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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=763003
• 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，宇宙中的大部分物质都是由质子构成的。精细结构常数决定了带电粒子之间以及光子（即光）之间的耦合强度。迄今为止，它已知为九位数字，并且已通过固态物理学和原子光谱学中的多种方法确定。需要更好地了解电子-光子相互作用理论（称为量子电动力学）的测试。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，人们不断推动更精确的知识。在这种情况下，质子电荷半径之谜极其重要。五年前，原子氢光谱遇到了障碍，因为对人造氢（实验室制造）的测量（其中电子被 μ 子取代）产生了不同的半径值（0.84 飞米），而不是 0.88 fm，通过常规氢光谱测量的组合来确定。 μ子氢的测定要精确得多，因为与电子相比，更重的μ子平均更接近质子，因此更灵敏。 0.88 fm 的大半径值已成为基本常数守护者 CODATA 世界组织公认的值，因为 2010 年最精确的电子-质子散射实验（来自德国美因茨）也支持该值。 -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。我们还建议解决目前美因茨和杰斐逊实验室（美国）测定之间存在的磁荷半径值之间的争议。在相关工作中，我们正在对一些常规氢谱实验（过去和当前在约克进行的实验）进行建模，以了解为什么过去的实验倾向于大电荷半径值。在更多应用领域，我们建议继续最近的工作水分子，这在放射治疗中很重要。我们将把目前对水的强电场电离的工作扩展到强激光场电离，目的是了解水在极端条件下的性质。这项工作扩展了我们在碰撞诱导电离和碎片方面最先进的工作，与实验结果非常吻合。