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Antihydrogen Physics

反氢物理学

基本信息

批准号：
EP/E048951/1
负责人：
Mike Charlton
金额：
$ 83.66万
依托单位：
Swansea University
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2007
资助国家：
英国
起止时间：
2007 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FE048951%2F1
关键词：
Antihydrogen Physics

项目摘要

Antihydrogen, the bound state of a positron and an antiproton, has recently been created under controlled conditions in the laboratory. The proposal seeks to exploit this advance by facilitating a new generation of experiments on antihydrogen held in a neutral trap, a so-called magnetic gradient trap. This is an arrangement of magnetic fields that acts upon the small magnetic moment of the anti-atom to produce a trapping force. However, such traps are shallow, and are currently only capable of holding antihydrogen in its ground state with kinetic energies equivalent to a temperature below 1 Kelvin. Thus, we need form antihydrogen with these low kinetic energies, a task not yet achieved. Once trapped, we hope to be able to do experiments to manipulate the antihydrogen, using electric and laser fields. Further into the future we hope to be able to produce very cold antihydrogen to make it possible to measure the gravitational interaction of antimatter. However, all experiments with antihydrogen are difficult, so the question we address here is; why bother? We will explain this using the example of symmetry.It has been apparent for a while that fundamental asymmetries are hidden deep within nature. For example, in the 1950's it was discovered that the weak nuclear interaction violates parity conservation. However, the defective parity mirror can be mostly repaired by adding so-called charge conjugation, which, loosely speaking, means that interactions are unaffected when every particle is substituted by its antiparticle. For a while it was believed that the laws of nature would obey the combination of parity reversal and charge conjugation. But by the mid-1960's this was found to be untrue for a small class of reactions involving unusual, fleeting, particles called K-mesons. Since then it has been assumed that the small blemish in the combined charge conjugation/parity reversal mirror can be corrected by the application of time-reversal.However, this 3-way switch differs from the three discrete symmetries, or any 2-way combination of them because the charge/parity/time combination exists as a theorem that can be proved using the basic postulates of quantum field theory. Such theories are the cornerstone of our current understanding of the Universe, but are widely recognised as being incomplete. So testing this unique 3-way switch is going to the heart of our understanding of nature. Our current picture of the beginning of the Universe involves the Big Bang, which is thought to have been an energetic event that created equal amounts of matter and antimatter. Why then did they not all annihilate one another and leave a Universe devoid of matter? Searches for large amounts of remnant antimatter in the Universe have, thus far, failed to find any trace. Currently it is thought that our Universe is matter dominant; in other words asymmetric. The other fact to add to this is that the amount of asymmetry we can currently identify via numerous studies of fleeting and rare particles isn't enough to explain the existence of the material Universe.Thus, it is only by probing the most basic symmetries that we can begin to understand how the Universe we observe came to be.

反氢，一个正电子和一个反质子的结合态，最近在实验室的受控条件下被创造出来。该提案试图利用这一进展，促进新一代的实验，反氢保持在一个中性的陷阱，所谓的磁梯度陷阱。这是一种磁场排列，作用于反原子的小磁矩，产生一种捕获力。然而，这样的陷阱很浅，目前只能将反氢保持在基态，其动能相当于低于1开尔文的温度。因此，我们需要用这些低动能形成反氢，这是一个尚未实现的任务。一旦被捕获，我们希望能够做实验来操纵反氢，使用电场和激光场。在更远的未来，我们希望能够产生非常冷的反氢，以便能够测量反物质的引力相互作用。然而，所有的反氢实验都是困难的，所以我们在这里要解决的问题是：为什么要这么麻烦呢？我们将用对称性的例子来解释这一点。一段时间以来，基本的不对称性显然隐藏在自然界的深处。例如，在20世纪50年代，人们发现弱核相互作用违反了宇称守恒。然而，有缺陷的宇称镜可以通过增加所谓的电荷共轭来修复，广义地说，这意味着当每个粒子被其反粒子取代时，相互作用不受影响。有一段时间，人们相信自然定律将服从宇称反转和电荷共轭的组合。但到了20世纪60年代中期，人们发现这对于一小类涉及不寻常的、转瞬即逝的、称为K介子的粒子的反应来说是不正确的。从那时起，人们就认为电荷共轭/宇称反转镜的小缺陷可以通过时间反转来修正。然而，这种三路开关不同于三种离散对称，或者它们的任何两路组合，因为电荷/宇称/时间组合是一个定理，可以用量子场论的基本假设来证明。这些理论是我们目前对宇宙理解的基石，但被广泛认为是不完整的。因此，测试这种独特的3路开关将成为我们理解自然的核心。我们目前对宇宙起源的看法涉及到大爆炸，这被认为是一个充满活力的事件，创造了等量的物质和反物质。为什么他们不互相毁灭，留下一个没有物质的宇宙呢？迄今为止，对宇宙中大量残余反物质的研究未能找到任何痕迹。目前，人们认为我们的宇宙是物质主导的;换句话说，不对称。另一个需要补充的事实是，我们目前通过对稍纵即逝的稀有粒子的大量研究所确定的不对称性的数量不足以解释物质宇宙的存在。因此，只有通过探索最基本的对称性，我们才能开始理解我们所观察到的宇宙是如何形成的。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Alternative method for reconstruction of antihydrogen annihilation vertices

重建反氢湮没顶点的替代方法

DOI：
10.1007/s10751-012-0588-5
发表时间：
2012
期刊：
Hyperfine Interactions
影响因子：
0
作者：
Amole C
通讯作者：
Amole C

Antihydrogen accumulation for fundamental symmetry tests.

DOI：
10.1038/s41467-017-00760-9
发表时间：
2017-09-25
期刊：
Nature communications
影响因子：
16.6
作者：
Ahmadi M;Alves BXR;Baker CJ;Bertsche W;Butler E;Capra A;Carruth C;Cesar CL;Charlton M;Cohen S;Collister R;Eriksson S;Evans A;Evetts N;Fajans J;Friesen T;Fujiwara MC;Gill DR;Gutierrez A;Hangst JS;Hardy WN;Hayden ME;Isaac CA;Ishida A;Johnson MA;Jones SA;Jonsell S;Kurchaninov L;Madsen N;Mathers M;Maxwell D;McKenna JTK;Menary S;Michan JM;Momose T;Munich JJ;Nolan P;Olchanski K;Olin A;Pusa P;Rasmussen CØ;Robicheaux F;Sacramento RL;Sameed M;Sarid E;Silveira DM;Stracka S;Stutter G;So C;Tharp TD;Thompson JE;Thompson RI;van der Werf DP;Wurtele JS
通讯作者：
Wurtele JS

Antihydrogen annihilation reconstruction with the ALPHA silicon detector