新物理模型中电弱相变的精确计算与相关唯象学研究

解释宇宙中正反物质不对称性的一阶电弱相变是超出标准模型新物理的一个研究热点。为了与相关实验结果进行比较，我们必须控制其理论计算的误差。微扰计算方法中，希格斯有效势中存在的诸多不确定因素，如规范参数、重整化方案、重整化能标和发散的处理方法等，每一项都会对相变强度和引力波谱的计算造成10%左右(个别情况能超过50%)的误差。同时，现有的相变数值计算方法也存在缺陷，如鞍点易误判、没有考虑多种相变路径等，有时会给出完全错误的结果。我们将以一个简单的模型(单个实标量单态场扩充模型)和一个复杂的模型(次最小超对称模型)为例，完善我们的相变数值计算方法，分析并减小理论不确定性对相变的关键温度、强度、成核温度和引力波信号的影响。进而与对撞机物理、暗物质物理和真空稳定性相结合，系统地研究这些模型的当前状态与未来探测的可能性。为新物理模型中相变精确计算提供参考方案和可靠的数值计算工具。

Strong first order electroweak phase transition for dynamically producing the matter-antimatter asymmetry in the Universe is one of the most popular topics in physics beyond the Standard Model. In order to accurately predict experimental observables, we need to reduce relevant theoretical uncertainties. In perturbative calculations, the uncertainties of Higgs effective potential include gauge fixing parameter, renormalization scheme, renormalization scale, the way of treating divergence, and so on. They can yield about 10% (sometime over 50%) relative difference in calculation of transition strength and gravitational wave spectrum. Meanwhile, there are several shortcomings in current numerical computation methods, such as easily misidentifying saddle point, omitting possibility of multiple transition paths, which may lead to totally wrong result. In this project, we will optimize our numerical computation method, analyze and try to reduce theoretical uncertainties in calculations of critical temperature, transition strength, nucleation temperature and gravitational wave spectrum, in a simple model (the Standard Model with a real singlet scalar) and a complex model (Next-to-Minimal Supersymmetric Standard Model). Finally, we want to comprehensively study these models with constraints from collider experiments, dark matter detection experiments, as well as dark matter relic density and electroweak vacuum stability which may be affected by phase transition of early universe. This project can provide a theoretical scheme of reference and a reliable numerical computation tool for precise calculation of electroweak phase transition in new physics models.