We review the theory and phenomenology of isosinglet vector-like quarks (VLQs). In recent years, interest in VLQs has been increasing, due to their contributions to new physics effects that can be tested in experiments at LHC and High-Luminosity LHC. The similarities of models with isosinglet VLQs and the seesaw framework in the leptonic sector are pointed out. The existence of VLQs leads to flavour-changing neutral currents at tree level and deviations from unitarity of the CKM matrix, introducing rich phenomenological implications. These new effects are naturally suppressed by the masses of the new quarks, that are constrained to be above the electroweak scale. In addition, striking new effects can be achieved with the inclusion of an extra complex scalar singlet. Such a minimal extension of the SM can give rise to new sources of CP violation with profound theoretical implications, allowing for a solution to the strong CP problem and a possible explanation for the baryon asymmetry of the Universe. We list and explain strong motivations to consider this class of models. We also briefly review how models with VLQs can be matched to the SM effective field theory (SMEFT). A detailed analysis of flavour observables that can be affected by the presence of VLQs is presented. Current bounds from collider searches of VLQs are summarized. We point out that the discovery of VLQs can be within the reach of present or future colliders being planned.

我们回顾了等单向量类夸克（VLQ）的理论和现象学。近年来，人们对 VLQ 的兴趣不断增加，因为它们对新物理效应的贡献可以在大型强子对撞机和高光度大型强子对撞机的实验中进行测试。指出了等单线 VLQ 模型和轻子扇区中跷跷板框架的相似之处。VLQ 的存在导致树级别的中性电流发生变化，并偏离 CKM 矩阵的幺正性，从而引入丰富的现象学含义。这些新效应自然会受到新夸克质量的抑制，这些新夸克的质量被限制在电弱尺度之上。此外，通过包含额外复杂的标量单态可以实现惊人的新效果。SM 的这种最小扩展可以产生具有深远理论意义的 CP 破坏的新来源，从而可以解决强 CP 问题并可能解释宇宙的重子不对称性。我们列出并解释了考虑此类模型的强烈动机。我们还简要回顾了如何将 VLQ 模型与 SM 有效场理论 (SMEFT) 相匹配。详细分析了可能受 VLQ 存在影响的可观察风味。总结了 VLQ 对撞机搜索的当前范围。我们指出，VLQ 的发现可以在当前或未来计划的对撞机的范围内实现。