The ZEPLIN-III Galactic Dark Matter Search

另请参阅PPARC关于暗物质的宣传和单张。从最早的时候起，人们就对宇宙进行了观测。自1933年和弗里茨·兹维基的测量以来，很明显，恒星、行星、气体和我们所知的其他一切太空中的物质，只占宇宙总含量的百分之几。现在压倒性的证据表明，宇宙中约有四分之一是所谓的暗物质，约有三分之二至四分之三是暗能量。暗物质和暗能量是什么，已经成为科学界最重要的问题之一。最好的候选人来自粒子物理学。在这里，我们对自然界基本构成要素的基本理解表明，我们所见过的所有粒子，如电子、夸克和中微子，实际上只是“存在”的所有粒子的一半。此外，还有超对称粒子，据预测，其中最轻的一个粒子正好具有解释暗物质所需的性质。因此，我们的预测是，当我们抬头看夜空时，我们看到的恒星实际上只是银河系的一小部分，其内容实际上是由被称为WIMP的非常弱相互作用的粒子组成的扩散光环所主导的，太阳和地球都在通过它。ZEPLIN-III合作的目标是实现世界上第一次直接探测暗物质和这些新粒子。ZEPLIN-III探测器包括一个8公斤的活性目标体积的氙气，保持足够低的温度，使其成为液体。偶尔，地球正在运行的暗物质的WIMP粒子中的一个会散射出氙核，当它发生散射时，它会产生一小束光，并释放出少量电荷。Zeplin-III被设计成能够看到这些微小的信号，揭示暗物质的存在。太空的自然辐射(宇宙射线)也可以做到这一点，因此探测器必须深埋在矿井下。提出ZEPLIN-III项目的合作伙伴在这一领域拥有丰富的经验。他们已经完成了ZEPLIN-I项目，目前正在分析ZEPLIN-II探测器的数据，并将ZEPLIN-III设计为有史以来最灵敏的暗物质实验。探测器本身已经建造和测试，由PPARC以前的赠款提供资金。这项赠款申请是为了提供资金，以完成所需的地下基础设施、屏蔽和否决系统，并允许在Boulby矿部署和在30个月内进行开采。

Please also see the PPARC publicity and leaflets on dark matter. From the earliest times, observations have been made of the Universe. Since 1933 and the measurements of Fritz Zwicky, it has become apparent that the stars, planets, gas and everything else we know of in space, is only a few percent of the total content of the Universe. The overwhelming evidence now suggests that about 1/4 of the Universe is in the form of so called dark matter, and about 2/3-3/4 is dark energy. What the dark matter and dark energy are has become one of the most important questions in science. The best candidate comes from particle physics. Here, our fundamental understanding of the basic building blocks of Nature suggests that all the particles we have ever seen, such as electrons, quarks and neutrinos, are in fact only half of all the particles that are 'out there'. In addition, there are 'supersymmetric' particles, and one of these, the lightest, is predicted to have precisely the properties needed to explain the dark matter. Hence, the prediction is that the stars we see when we look up at the night sky are in fact only a small component of the Galaxy, the content in fact being dominated by a diffuse halo of very weakly interacting particles, known as WIMPs, through which the Sun and Earth are moving. It is the goal of the ZEPLIN-III collaboration to make the World's first direct detection of dark matter and these new particles. The ZEPLIN-III detector comprises an active target volume of 8 kg of xenon, kept cold enough to be a liquid. Occasionally, one of the WIMP particles of the dark matter through which the Earth is moving will scatter off a nucleus of the xenon, and when it does it will generate a small flash of light and the liberation of a small amount of electrical charge. ZEPLIN-III is designed to be able to see these small signals, revealing the presence of the dark matter. The natural radiation of space (cosmic rays) could also do this, and so the detector has to be buried deep underground in a mine. The collaboration proposing the ZEPLIN-III project have great experience in this field. They have already completed the ZEPLIN-I project, are presently analysing data from the ZEPLIN-II detector, and have designed ZEPLIN-III to be the most sensitive dark matter experiment ever. The detector itself has already been built and tested, having been funded through previous PPARC grants. This grant application is to provide funds to complete the required underground infrastructure, shielding and veto systems, and to allow deployment in the Boulby mine and exploitation over a period of 30 months.