Beyond the Standard Model Scenarios: Dark Matter and Collider Signals

粒子物理标准模型是历史上最成功的科学理论之一。它可以用几个对称性原理和几个自然常数来解释大范围的亚原子现象。然而，我们有很好的理由相信，标准模型并不是关于物质基本结构问题的最终答案。一方面，存在关于模型中的参数的调整的理论关注。另一方面，实验证据，例如中微子味振荡和暗物质（对星系的形成至关重要）的存在，在标准模型中仍然无法解释。人们普遍认为，这些谜题的解决方案需要新粒子和/或新相互作用的存在。不幸的是，尽管有许多超越标准模型的物理预测，但没有确凿的证据证明存在新的粒子或相互作用。关于为什么新粒子到目前为止没有被探测到，有两种可能的解释。首先，它们可能太重，无法在目前的实验中生产。到目前为止，我的大部分研究都集中在这个想法上，在我的新研究项目中，我想重新审视这种可能性，并对所涉及的假设进行仔细研究（使用新开发的软件），目的是扩大新粒子和新相互作用的参数空间。第二种可能是新粒子被隐藏起来了，因为它们与普通物质的耦合非常微弱。这可能是因为它们产生的速率太小，或者它们形成了一个压缩的光谱，也就是说，一个不容易产生观测信号的光谱。在这种情况下，最有希望的策略是进行更精确的测量，并增加实验中的事件数量（强度边界）以找到它们。我建议设计一些搜索在大型强子对撞机通过选择观测与小干扰的背景，并补充搜索质子-质子碰撞，寻找这些粒子在重离子碰撞。

The Standard Model of Particle Physics is one of the most successful scientific theories in history. It can explain a wide range of subatomic phenomena in terms of a few symmetry principles and a handful of constants of nature. There are however, very good reasons to believe that the Standard Model is not the final answer to questions about the fundamental structure of matter. On one hand, there are theoretical concerns about the tuning of the parameters in the model. On the other hand, experimental evidence such as the neutrino flavour oscillations and the existence of dark matter (crucial for the formation of galaxies) remains unexplained in the Standard Model. It is widely believed that the solution to these puzzles requires the existence of new particles and/or new interactions. Unfortunately, although many predictions of beyond the Standard Model physics are available, no conclusive proof of new particles or interactions exists. There are two possible explanations as to why new particles may have escaped detection so far. First, they could be too heavy to be produced in current experiments. Most of my research has been concentrated so far on this idea, and in part of my new research project, I would like to revisit this possibility, and perform a careful study of the assumptions involved (using newly developed software), with the purpose of widening the parameter space still available for new particles and new interactions. A second possibility is that the new particles are hidden, because they couple so feebly to ordinary matter. It may be that the rate at which they are produced is too small, or alternatively, that they form a compressed spectrum, that is, one which does not easily yield observed signals. In this case, the most promising strategy would be to make more precise measurements, and to increase the number of events in experiments (intensity frontier) to find them. I propose to devise some searches at the LHC by choosing observables with little interference from the background, and complimentary to searching in proton-proton collisions, to look for these particles in heavy ion collisions.