Determining the thermal history of electroweak symmetry breaking is a forefront challenge for particle physics and cosmology. The occurrence of a first order electroweak phase transition (EWPT) would have profound implications for explaining the origin of the cosmic baryon asymmetry and generation of primordial gravitational radiation. I discuss recent theoretical developments in assessing the...
The discovery of the Higgs boson marked the beginning of a new era in HEP. Precision measurement of the Higgs boson properties and exploring new physics beyond the Standard Model using Higgs as a tool become a natural next step beyond the LHC and HL-LHC. Among the proposed Higgs factories worldwide, the Circular Electron Positron Collider (CEPC) with 100km circumference was proposed by the...
Will talk about cosmic phase transition and nano-hertz gravitational waves is given. Two examples of new physics models are illustrated, which respectively predict a supercool first-order electroweak phase transition and a first-order phase transition in the dark sector at MeV scale. Both models are shown to be able to explain the reported evidences of nano-hertz gravitational waves.
We explore the fermion oscillation in a degenerate environment. The direct consequence is introducing a Pauli blocking factor 1−fi, where fi is the phase space distribution function, for each intermediate mass eigenstate during propagation. It is then much easier for a state with larger existing fraction or density to oscillate into other states with less degeneracy while the reversed process...
In this talk I will review the progress of using LIGO events to probe/constrain the parameter space of Axion-like particles (ALPs), which may be generated through the super-radiant process around rotating black holes, and/or coupling with nuclear matter around neutron stars. I will also discuss current efforts trying to understand dynamical effects induced by ALP clouds in a compact object...
I will discuss the phenomenological consequencies of phase transitions happened during inflation.
Abstract: A variety of supergravity and string-based models feature hidden sectors with U(1) gauge groups, playing significant roles in particle physics and cosmology. As constraints on dark matter tighten, exploration into these hidden sectors intensifies. These hidden sectors can engage in feeble interactions with the visible sector and vary between feeble and normal strength with each...
Phase transition gravitational waves could be a novel probe for fundamental physics in the near future. Hence, precise calculation of phase transition gravitational waves is essential for detecting the sign of new physics. I will discuss a framework that could allow us to omit some unnecessary approximations and give a relatively more accurate calculation of gravitational waves generated by...
Cosmological first-order phase transitions (FOPTs) serve as comprehensive probes into our early Universe with associated generations of stochastic gravitational waves and superhorizon curvature perturbations or even primordial black holes. In characterizing the FOPT, phenomenological parameters like transition temperatures, strength factors, bubble separations, and energy budgets can be...
Radiative symmetry breaking (classically conformal) theories are plausible solution to the hierarchy problem. Such a paradigm also induces very rich cosmological implications via first-order phase transitions in the early Universe. This talk will discuss those effects.
We present a consistent derivation of the complete Wess-Zumino-Witten interactions of axions, including the counter-term necessary to guarantee the gauge invariance of the Standard Model. By treating the derivative of the axion field as a background gauge field and incorporating auxiliary chiral rotation phases, we ensure consistency in the axion-interaction Lagrangian. This approach allows us...
The rotation effect on the QCD phase structure is still an open question: Lattice simulations favor confinement but model calculations favor deconfinement. We discuss this problem in the frame of resumed QCD.
Understanding the properties of quark matter and its phase structure is crucial for advancing our knowledge of the universe's evolution and the composition of visible matter. Over the past two decades, numerous experimental observations have provided evidence for the existence of strongly interacting quark-gluon plasma (sQGP) in relativistic heavy-ion collisions. As a result, exploring the QCD...
This talk will review the current status of the glueball relevant lattice QCD study.
Using the static and spherically symmetric metric for a black hole immersed in dark matter (DM) halos with Hernquist, Burkert, and Navarro-Frenk-White density distributions, we study the possibility of the detection of DM halos and the distinction between different DM halos with the extreme mass ratio inspiral systems (EMRIs). We also consider gravitational waves from the EMRIs consisting of...
Several pulsar timing array collaborations recently reported evidence of a stochastic gravitational wave background (SGWB) at nHz frequencies. While the SGWB could originate from the merger of supermassive black holes, it could be a signature of new physics near the 100 MeV scale. Supercooled first-order phase transitions (FOPTs) that end at the 100 MeV scale are intriguing explanations,...
We consider the intriguing possibility that the recently reported nano-Hz gravitational wave signal by Pulsar Timing Array (PTA) experiments is sourced by a strong first-order phase transition from a nearly conformal dark sector. The phase transition has to be strongly supercooled to explain the signal amplitude, while the critical temperature has to be in the ${\cal O}(GeV)$ range, as...
We calculated the gravitational waves induced by different QCD phase transitions including in a chirality imbalanced system, in pure gluon system, in PQM, QM, and Friedberg-Lee model, and the gravitational waves can be detected by LISA, Taiji and DECIGO. We find that the values of inverse duration $\beta/H$ of these QCD phase transitions are of order
$10^4$ or $10^5$, which means the phase...
We discuss a QCD-scale composite axion model arising from dark QCD coupled to QCD. The presently proposed scenario not only solves the strong CP problem, but also is compatible with the preheating setup for the QCD baryogenesis. The composite axion is phenomenologically required to mimic the QCD pion, but can generically be flavorful, which could be testable via the induced flavor changing...
In order to study the validity of analytical formulas used in the calculation of characteristic physical quantities related to vacuum bubbles, we conduct several numerical simulations of bubble kinematics in the context of cosmological first-order phase transitions to determine potentially existing systematic uncertainties. By comparing with the analytical results, we obtain the following...
Ref: https://arxiv.org/abs/2306.00641
Science Bulletin (doi:10.1016/j.scib.2024.06.003)
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...
Firstly, we discuss how the beyond the Standard Model hypothetical particle, the axion, can produce gravitational waves through several different mechanisms either in the astrophysical setting or the early universe. Then we present our recent new detection proposals for axions/gravitational waves using cryogenic quantum transport technology. The electric signal is enhanced by the high-quality...
We systematically discuss the new dark matter formation mechanism from a cosmological first-order phase transition and its associated gravitational wave signals.
暗色区是新物理模型构造中常见的一个对象，其早期的相变可能是一级相变，从而产生随机引力波信号。但研究的非微扰性是一个困难，本报告将简要介绍其相关方面及其进展。
As one of the major dark matter candidates, the ultralight Axion-Like Dark Matter (ALDM) exhibits a pronounced wave nature on astronomical scales and offers a promising solution to small-scale structure issues within local galaxies. While the linearly polarized pulsar light travels through the ALDM galactic halo, its position angle (PA) can be subject to an oscillation induced by the ALDM...
The strong CP problem and dark matter candidates are two significant challenges for the Standard Model. QCD axions are regarded as the most natural solution to the strong CP problem, making the development of a UV-complete model and the precision testing of their theoretical framework critical. As potential dark matter candidates, axion-like particles (ALPs) have garnered significant attention...
This talk plans to introduce a couple of recent new phenomenologies and cosmology related to the QCD phase transition epoch, coupled to Beyond the Standard Model, in the thermal history of the universe. Baryogenesis with a QCD-induced dynamical chemical potential (a la Higgs relaxation mechanism), strong CP problem, and gravitational wave predictions will be covered in scenarios of this class,...
Neutron stars (NS) situated in dark matter (DM)-rich environments can capture DM particles. The captured DM particles can thermalize, form a gravitationally bound core, and eventually form a black hole inside the NS. After accreting the surrounding material, the black hole can destroy the NS. In light of this, we constrain DM microphysics from the survival of the neutron star. In this talk, we...
There are two common methods to compute the bubble wall velocity for the cosmological phase transitions: the fluid method, which analyzes the macroscopic fluid system, and the local Boltzmann equations; the microscopic method, which studies the force acting on the bubble wall by the particle interactions. However, those two methods are not consistent with each other. In this study, we present...
Primordial black holes (PBHs) may form before cosmological first-order phase transitions, leading to inevitable collisions between PBHs and bubble walls. In this Letter, we have simulated for the first time the co-evolution of an expanding scalar wall passing through a black hole with full numerical relativity. This black hole-bubble wall collision yields multiple far-reaching phenomena...
Recent observations of nHz stochastic gravitational waves (GW) by Pulsar Timing Arrays (PTA), such as NANOGrav, have disfavored the existence of topologically stable cosmic strings. However, cosmic metastable strings and superstrings remain viable candidates. Gravitational waves from all classes of strings generally span a wide range of frequencies, which conflicts with LIGO’s non-observation...
The chiral phase transition in QCD can be supercooled in the thermal history of the universe to be instantaneously out-of equilibrium, if QCD is coupled to a dark QCD sector exhibiting the dark chiral phase transition of the first order. In that case the QCD sigma meson field (as the chiral order parameter, or the light quark condensate) starts to roll in a nonadiabatic way down to the true...
We argue that the axionic domain-wall with a QCD bias may be incompatible with the NANOGrav 15-year data on a stochastic gravitational wave (GW) background, when the domain wall network collapses in the hot-QCD induced local CP-odd domain. This is due to the drastic suppression of the QCD bias set by the QCD topological susceptibility in the presence of the CP-odd domain with nonzero $\theta$...
Domain wall is one of the topological defects that can be created during phase transitions. The minimal and most well-studied domain wall is from $Z_2$ symmetry breaking. In this talk, we will go beyond this minimal case in two ways: embedding the $Z_2$ symmetry into a $U(1)$ and generalising the abelian discrete symmetry to non-abelian ones. On the one hand, the $Z_2$ symmetry can result from...
Primordial black holes may be produced from cosmological first-order phase transitions. I will discuss a new mechanism for PBH formation based on an aborted heating phase transition during reheating. Here "heating" means that the phase transition occurs as the temperature increases during the earlier stage of reheating (when the Universe is still matter-dominated). "Aborted" means that there...
The prospect of detecting Gravitational waves from first order phase transitions opens up a whole new way to test particle physics models. However in order to make use of this we need to have an understanding of the uncertainties involved involved in theoretical calculations and the reliability of commonly used approximations. I will discuss various subtle issues in the prediction of...
If millicharged particles (MCPs) exist they can be created in the atmosphere when high energy cosmic rays collide with nuclei and could subsequently be detected at neutrino experiments. We extend previous work, which considered MCPs from decays of light mesons and proton bremsstrahlung, by including production from $\Upsilon$ meson decays and the Drell-Yan process. MCPs with masses below a GeV...
