Probing the Early Cosmological History with Dark Matter

该奖项资助新墨西哥大学Rouzbeh Allahverdi教授的研究活动。我们从观测中得知，宇宙中只有15%的物质可以用粒子物理学的标准模型来描述，而85%的物质是由暗物质组成的。然而，暗物质的性质和起源仍然是粒子物理学和宇宙学交叉领域最深奥的问题之一。一系列的暗物质探测实验，结合大型强子对撞机（LHC）的实验，将帮助我们发现暗物质并确定其粒子物理起源。这些实验提供的补充信息也将在研究如何确定当前暗物质的能量密度方面发挥关键作用。这项由该奖项资助的研究将结合暗物质的理论模型和观测特征来探索早期宇宙历史。因此，该领域的研究通过促进科学在其最基本的方向之一的进步来促进国家利益：发现和理解新的物理定律。由该奖项资助的研究也将产生重大而广泛的影响。Allahverdi教授将让研究生和本科生参与他的研究，从而为在该领域开始研究的初级物理学家提供重要的培训。此外，PI还将通过工作见习和对高中生的指导，以及访问学校和公开演讲，将他的成果传播给更广泛的受众。从技术上讲，该奖项支持的研究侧重于利用暗物质来探测宇宙年龄不到一秒时的热历史。它包括对暗物质模型和生产机制的研究，有三个目标。首先，PI希望利用粒子物理实验和宇宙学观测来重建早期宇宙的热历史。其次，PI希望通过利用它们独特的可观测特征来限制新的暗物质产生机制。第三，PI希望研究粒子物理模型，这些模型不仅可以容纳暗物质，还可以解决宇宙的物质-反物质不对称问题，并探索这些模型的新的可测试预测。为了实现这些目标，Allahverdi教授将建立新的暗物质粒子物理模型，研究暗物质在一秒之前的不同热历史中的产生，并研究可以在各种实验中测试的不同产生机制的新预测。这些调查将帮助我们确定DM的更深层次的理论起源及其在基本理论中的嵌入。它们还将使我们能够探测宇宙的热历史，这是我们目前最好的观测探测器——即宇宙微波背景和大爆炸核合成——无法探测到的。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award funds the research activities of Professor Rouzbeh Allahverdi at the University of New Mexico.We know from observations that only 15% of the matter in the universe is described by the Standard Model of particle physics, while 85% is made of dark matter. However, the nature and origin of dark matter remains one of the most profound problems at the interface of particle physics and cosmology. A whole array of dark-matter detection experiments, combined with experiments at the Large Hadron Collider (LHC), will help us discover the dark matter and establish its particle-physics origin. The complementary information provided by these experiments will also play a crucial role in examining how the present-day energy density of the dark matter was determined. The research funded by this award will combine theoretical models and observational signatures of dark matter to probe the early cosmological history. Research in this area thus advances the national interest by promoting the progress of science in one of its most fundamental directions: the discovery and understanding of new physical law. The research funded by this award will also have significant broader impacts. Professor Allahverdi will involve graduate and undergraduate students in his research, and thereby provide critical training to junior physicists beginning research in this field. The PI will additionally bring his results to a broader audience through job shadowing and mentorship of high-school students, as well as by visiting schools and giving public lectures.More technically, the research supported by this award focuses on using dark matter to probe the thermal history of the universe when it was a tiny fraction of a second old. It includes investigations of dark-matter models and production mechanisms having a three-fold goal. First, the PI wishes to use particle physics experiments along with cosmological observations to reconstruct the thermal history of the early universe. Second, the PI wishes to constrain novel dark-matter production mechanisms by employing their distinct observable signatures. Third, the PI wishes to study particle-physics models that not only accommodate dark matter but also address the matter-antimatter asymmetry of the universe, and explore the novel testable predictions of such models. To achieve these objectives, Professor Allahverdi will build new particle-physics models of dark matter, study dark-matter production in alternative thermal histories before one second, and investigate the novel predictions of different production mechanisms that can be tested in various experiments. These investigations will help us determine the deeper theoretical origin of the DM and its embedding within a fundamental theory. They will also enable us to probe the thermal history of the universe that is out of the reach of our best observational probes --- namely the cosmic microwave background and Big Bang nucleosynthesis --- at the present time.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.