Electron-Positron Experimental Particle Physics

人们普遍认为，一些最常见的基本粒子的最基本成分是夸克，以及它们的反物质对应物——反夸克。通过探测这些粒子的存在和结构，有可能了解控制夸克和反夸克物质的基本原理。该项目的工作将使用日本高能加速器研究组织（KEK）实验室Belle实验收集的数据来测量由夸克-反夸克对组成的介子粒子的形成。通过研究这些介子，人们可以探索基本的物理过程，如电荷宇称（CP）破坏、罕见介子衰变和可能表明暗物质存在的外来粒子的存在。这项工作特别注重对学生的支持，从而有助于培养急需的高科技劳动力。Belle是围绕一个非对称正电子对撞机的相互作用区域建造的，电子的能量为8 GeV，正电子的能量为3.5 GeV，质心能量为10.58 GeV。Belle的主要目标是探测由夸克-反夸克对组成的介子，特别是由粲夸克（charmonium）和底夸克（bottomonium）组成的介子。日本KEK的Belle实验拥有世界上最大的底部共振数据样本：upsilon (5S), upsilon （2S）和upsilon （1S）。该项目的中心目标是在10 GeV的质能中心进行非常精确的碎片化（共振粒子如upsilon的分裂）和强子化（初始态夸克和胶子衰变成可探测粒子如介子和光子的过程）的细节测量。这将提供量子色动力学（QCD）的测试，为理论点阵QCD计算提供详细信息。upsilon（1S）共振对胶子和光子的衰减提供了QCD强耦合常数的精确测量。

It is widely believed that the most fundamental constituents of some of the most common elementary particles are quarks, and their anti-matter counterpart, anti-quarks. By probing the existence and structure of these particles, it is possible to learn about the underlying principles governing quark and anti-quark matter. The work in this project will use data collected at the Belle experiment at the High Energy Accelerator Research Organization (KEK) laboratory in Japan to measure the formation of particles known as mesons that consist of a quark-antiquark pair. By studying these mesons, one can probe fundamental physics processes such as Charge Parity (CP) violation, rare meson decays and the existence of possible exotic particles which could indicate the presence of Dark Matter. This effort has a particular focus on the support of students, thereby contributing to the development of a much-needed high tech workforce.Belle is built around the interaction region of an asymmetric electron-positron collider, with electrons having the energy of 8 GeV and positrons having the energy of 3.5 GeV, giving 10.58 GeV center-of-mass energy. The main goal of Belle is to detect mesons made of a quark-anti-quark pair, in particular those mesons made of charm quarks (charmonium) and bottom quarks (bottomonium). The Belle Experiment at KEK in Japan has the world's largest data samples recorded at the bottomonium resonances: upsilon (5S), upsilon (2S) and upsilon (1S). The central aim of this project is to perform very precise measurements of details of fragmentation (the break-up of resonant particles such as the upsilon) and hadronization (the process of initial state quarks and gluons decaying into detectable particles like pions and photons) at a center of mass energy of 10 GeV. This will provide tests of Quantum Chromo-Dynamics (QCD), providing detailed information for theoretical Lattice QCD calculations. The decays of the upsilon(1S) resonance to gluons and photons provides a precise measurement of the QCD strong coupling constant.