Hadron phenomenology using holographic light-front Quantum Chromodynamics

使用全息光前量子色动力学的强子现象学

• 批准号: SAPIN-2020-00051
• 负责人: Sandapen, Ruben
• 金额: $ 1.09万
• 依托单位: Acadia University
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=718913
• 关键词: Hadron; phenomenology; using; holographic; light

There are four known fundamental interactions in Nature and this proposal investigates one of the them: the strong interaction which is responsible for binding quarks together in hadrons and nucleons together in atomic nuclei. It is thus the underlying interaction for both hadronic and nuclear physics. We do have a fundamental theory for the strong interaction: Quantum Chromodynamics (QCD) and it tells us how quarks interact by exchanging gluons and also how gluons interact between themselves by exchanging other gluons. However, the equations of QCD are extremely difficult to solve exactly when the coupling between the interacting particles is strong. Experimentally, isolated quarks (or gluons) are never observed, i.e. our detectors only see hadrons. Understanding the permanent confinement of quarks and gluons inside hadrons from first principles in QCD remains to this day an open problem. Consequently, hadronic physics remain largely phenomenological. But phenomenology is what allows theory and experiment to mutually guide and reinforce each other, it is a key element to progress in science. New insights into strongly-coupled QCD comes from conjecture, proposed by Juan Maldacena (Princeton) in the late nineties, of a mathematical equivalence between special classes of quantum theory (without gravity) in 4-dimensional spacetime and a classical (not quantum) gravity theory in a higher dimensional spacetime. The usefulness of this equivalence is due to the fact that if the quantum theory is strongly-coupled, its gravity dual is weakly-coupled. Hence, one can obtain information on the hard-to-solve quantum theory by solving instead its easy-to-solve gravity dual. Unfortunately, the gravity dual to QCD is not known. But gravity duals to approximate versions of QCD are known and one of them is referred to as light-front holographic QCD. This research focuses on the phenomenology of light-front holographic QCD to understand hadronic structure and how the latter affects the physics of rare decays of the B meson. Such decays are extraordinarily sensitive probes to new physics beyond the Standard Model (SM). In the recent years, a number of discrepancies between SM predictions and experimental data have been observed at the Large Hadron Collider (LHC) in Europe. A better understanding of hadronic structure will shed light on these discrepancies. At the same time, this research will serve to interpret and guide future experiments on hadronic structure from other facilities like the Jefferson Lab in the US. This research contributes to the training of the next generation of Canadian researchers by introducing them to highly sophisticated mathematics and computational tools and giving them the opportunity to use real world data coming from particle colliders around the world. It also sustains the prominent Canadian role at the forefront of world-class research in addressing one of the most fundamental questions in contemporary particle physics.

自然界中有四种已知的基本相互作用，该提案研究了其中一个：强烈的相互作用，该相互作用负责在原子核中将夸克和核中结合在一起。因此，它是耐药物理和核物理的潜在相互作用。我们确实具有强大相互作用的基本理论：量子染色体动力学（QCD），它告诉我们夸克如何通过交换胶子交换以及胶子如何通过交换其他胶子来相互作用。但是，当相互作用粒子之间的耦合强烈时，QCD的方程非常困难。在实验上，永远不会观察到孤立的夸克（或胶子），即我们的探测器只看到黑色子。从QCD中的第一原则中了解夸克和脾气的永久性限制至今仍有一个开放的问题。因此，野药物理学在很大程度上仍然是现象学。但是现象学使理论和实验可以相互指导和加强，这是科学进展的关键要素。 对强耦合QCD的新见解来自猜想，这是由胡安·马尔达纳（Juan Maldacena）（普林斯顿）在九十年代晚期提出的，在四维时空中的特殊类别的量子理论（无重力）与较高的上限频中的量子理论的特殊类别（无重力）之间的数学等效性。这种等价的有用性是由于以下事实：如果量子理论是强耦合的，则其重力双重偶联是弱耦合的。因此，人们可以通过求解其易于解决的重力双重的求解来获取有关难以解决的量子理论的信息。 不幸的是，QCD的重力双重双重二。但是重力双重二的QCD已知，其中一个被称为轻质全息QCD。这项研究着重于轻率全息QCD的现象学，以了解望子的结构以及后者如何影响B梅森的罕见衰变物理学。除标准模型（SM）之外，这种衰减对新物理学非常敏感。 近年来，在欧洲的大型强子对撞机（LHC）上观察到了SM预测与实验数据之间的许多差异。更好地理解望子结构将阐明这些差异。同时，这项研究将有助于解释和指导从美国杰斐逊实验室（Jefferson Lab）等其他设施的HADRONIC结构进行的未来实验。 这项研究通过向加拿大研究人员介绍了高度复杂的数学和计算工具，并为他们提供了使用来自世界各地粒子煤矿的现实世界数据的机会，从而为加拿大研究人员的培训做出了贡献。它还维持了加拿大在世界一流研究的最前沿的重要角色，以解决当代粒子物理学中最基本的问题之一。