The correlation functions of large-scale fluctuations are crucial observables in modern cosmology. There have been considerable efforts in the analytical study of cosmological correlators in recent years. In this talk, I will introduce the basic structure of cosmological correlators and several analytical methods we recently proposed for computing them. In particular, I will describe the...
近期脉冲星计时阵列合作组发现了纳赫兹引力波背景的关键证据。学术界掀起有关引力波源的诸多讨论，除超大质量黑洞外，宇宙学源也受到强烈关注。本报告将着重介绍次级引力波的研究进展。我们将探讨原初非高斯性对次级引力波的重要贡献，并在此基础上分析纳赫兹引力波探测数据，进而尝试解决原初黑洞的过量产生问题。进一步地，我们提出表征次级引力波各向异性的角功率谱可作为原初非高斯性的有力探针。我们预期引力波探针将在原初黑洞暗物质和宇宙起源研究中扮演重要角色。
宇宙一阶相变引力波提供了粒子物理研究的新手段，在国内和国际上得到了广泛的研究。
在这一报告中，我将介绍此前很少被考虑的相变中的耗散效应，并讨论强耗散效应下相
变图像及引力波发生的改变。
The recently released data by pulsar timing array collaborations present strong evidence for a stochastic signal consistent with a gravitational-wave background. In this talk, I will discuss some implications for scalar-induced gravitational waves with pulsar timing arrays.
Ref: https://arxiv.org/abs/2306.00641
Results from a wide range of searches targeting different experimental signatures with and without missing transverse momentum ($E^{miss}_T$) are used to constrain a Two-Higgs-Doublet Model (2HDM) with an additional pseudo-scalar mediating the interaction between ordinary and dark matter (2HDM+a). The analyses use up to 139 fb$^{−1}$ of proton-proton...
The Witten effect implies the electromagnetic interactions between axions and magnetic monopoles. Based on the quantum electromagnetodynamics, a generic low-energy axion-photon effective field theory was built by introducing two four-potentials ($A^\mu$ and $B^\mu$) to describe a photon. More anomalous axion-photon interactions and couplings ($g_{aAA}$, $g_{aBB}$ and $g_{aAB}$) arise in...
We investigate the first-order phase transition catalyzed by primordial black holes~(PBHs) in the early Universe. We find that super-horizon curvature perturbations generated in this scenario lead to the production of gravitational waves when the scalar modes re-enter the horizon. If PBHs with masses about $10^{-13}M_{\odot}$ constitute all dark matter, the first-order electroweak phase...
In this talk, I will review indirect searches for new physics at LHCb.
We thoroughly explore the cosmic gravitational focusing of cosmic neutrino fluid (CνF) by dark matter (DM) halo using both general relativity for a point source of gravitational potential and Boltzmann equations for continuous overdensities. Derived in the most general way for both relativistic and non-relativistic neutrinos, our results show that the effect has fourth power dependence on the...
Ultralight bosonic fields (ULBFs) are predicted by various theories beyond the standard model of particle physics and are viable candidates of cold dark matter. There have been increasing interests to search for the ULBFs in physical and astronomical experiments. In this paper, we investigate the sensitivity of several planned space-based gravitational-wave interferometers to ultralight scalar...
We evaluate Feynman integrals by hypergeometric function method.
Multiple EW vector boson amplitudes are known to have bad energy behavior for individual Feynman diagrams, which causes many problems for numerical and theoretical analysis. Based on Goldstone equivalence theorem(GET), we introduce a new representation of Feynman rules that makes GET manifest, while reproduces the exact results of the amplitudes. The new helicity has no subtle gauge...
通常文献中对于Z'粒子的探测都假定Z'与Z玻色子的共振峰相距甚远。当Z'与Z粒子近简并且可能有强烈混合时，文献中缺乏详细的讨论。在这种情况下，Z'和Z的共振峰可能很难分开，过去对撞机上的探测结论都失效了。针对这种情况，我们模拟了一种类似LEP的探测器，通过探测Z'-Z重叠共振峰的形状，讨论了这种探测器对于Z'粒子探测的敏感度。我们进一步以CEPC为例，讨论了有关探测器的敏感度。
The study of polarimetric features during the prompt phase of Gamma-ray Bursts (GRBs) has been essential for elucidating the debated emission mechanisms and gaining insight into the inner structure of GRBs. However, the potential impact of photon-Axion-Like-Particles (ALPs) mixing in extragalactic magnetic fields, leading to significant modifications in the initial polarization, has been...
In our galaxy, the white dwarfs (WDs) will inevitably capture the dark matter (DM) particles streaming through them, if there exist interactions between DM particles and nuclei/electrons. At the same time, these DM particles can also be evaporated by the nuclei/electrons in a WD if they have proper mass and the WD is not too cold. The evaporation of DM particles will lead to a faster cooling...
The XENONnT experiment, located in Laboratori Nazionali del Gran Sasso (LNGS), is a direct detection experiment designed to search for Weakly Interacting Massive Particles (WIMPs) using a dual-phase time projection chamber with 8.5 tonnes of xenon. The experiment began collecting science data in 2021 and is currently in operation. In its first science run (SR0), the experiment achieved an...
We present an improved analysis of the top-quark pair production via the process $ e^{+}e^{-} \to \gamma^{*} \to t\bar{t}$ near the threshold region up to next-to-next-to-next-to-leading order (N$^{3}$LO) QCD corrections. Near the threshold region, the top-quark velocity $v$ tends to zero, leading to Coulomb singularity. To achieve a reasonable prediction in the threshold region, we...
Traditionally a cosmic first-order phase transition proceeds by nucleating handful of bubbles through quantum tunneling. However, the presence of domain walls during the transition may greatly enrich the way phase transitions are completed. In this talk we develop the bubble-free mechanism, which constitutes a competing means of accomplishing the phase transition where bubble nucleation is...
There is growing evidence that the early Universe experienced inflationary expansion, yet no consensus has been drawn on the details. Meanwhile, neutrino physics is entering a precision era, making more information on masses and mixings available. We consider a neutrino path to the early Universe confronting the situation above. With right-handed neutrinos (RHNs) coupling to the inflaton, the...
