The China Dark Matter Experiment (CDEX) pursues direct searches of light dark matter particles and neutrinoless double beta decay at the China Jinping Underground Laboratory (CJPL), which is the deepest operating laboratory for astroparticle research.
The CDEX employs germanium semi-conductor detector which has low energy threshold and excellent energy resolution. We report the latest novel...
PandaX experiment uses xenon as target to detect weak and rare physics signals, including dark matter and neutrinos. We are running a new generation detector with 4-ton xenon in the sensitive volume, PandaX-4T. The commissioning run data has pushed the constraints on WIMP-nucleon scattering cross section to a new level. In this talk, I will give an overview of PandaX-4T latest results on dark...
Pulsar timing arrays (PTAs) consisting of widely distributed and well-timed millisecond pulsars can serve as a galactic interferometer to detect gravitational waves. With the same data acquired for PTAs, we propose (https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.130.121401) to develop pulsar polarization arrays (PPAs), to explore astrophysics and fundamental physics. As in the case...
We would like to present our recent study of the four-body baryonic $B\to{\bf B_1\bar B'_1 B_2\bar B'_2}$ decay. We explain the branching fraction of $\bar B^0\to p\bar p p\bar p$ measured by LHCb as small as $2.2\times 10^{-8}$. We also predict the following branching fractions: ${\cal B}(B^-\to n\bar p p\bar p)=(8.4^{+2.1}_{-1.0}\pm 0.4^{+3.4}_{-1.9})\times 10^{-8}$, ${\cal B}(B^-\to...
In this talk, I will talk about the production of sub-GeV DM from the cosmic ray collision with the atmosphere and the prospects in direct detection. I will highlight the importance of quasi-elastic scattering in the earth-stopping effect.
The Witten effect implies interaction between axion and magnetic monopole, and the quantum electromagnetodynamics (QEMD) properly describes electric charges, magnetic charges and photons. Based on the QEMD, a generic low-energy axion-photon effective field theory can be built. This generic axion-photon Lagrangian introduces the interactions between axion and two four-potentials, and leads to...
Motivated by the collisionless cold dark matter small scale structure problem, we propose an asymmetric dark matter model where dark matter particle interact with each other via a massive dark gauge boson. This model easily avoid the strong limits from cosmic microwave background (CMB) observation, and have a large parameter space to be consistent with small scale structure data. We focus on a...
Light millicharged particles can be copiously produced from meson decays in cosmic ray collisions with the atmosphere, leading to detectable signals in large underground neutrino detectors. In this paper we study a new channel to produce millicharged particles in the atmosphere, the proton bremsstrahlung process. We find that the proton bremsstrahlung channel can produce a much larger flux of...
We present the Gel'fand-Kapranov-Zelevinsky (GKZ) hypergeometric systems of the Feynman integrals of the three-loop vacuum diagrams with arbitrary masses, basing on Mellin-Barnes representations and Miller's transformation. The codimension of derived GKZ hypergeometric systems equals the number of independent dimensionless ratios among the virtual masses squared. Through GKZ hypergeometric...
We explore the potential of precision cosmological data to study non-minimal dark sectors by updating the cosmological constraint on the mirror twin Higgs model (MTH). The MTH model addresses the Higgs little hierarchy problem by introducing dark sector particles. In the early Universe, the mirror baryon and mirror radiation behave as dark matter and dark radiation, and their presence modifies...
Inflation correlators encode ultra-high-energy physics at the inflation scale and are promising targets for future cosmological observations. Theory-wise, these objects are boundary correlators of bulk dS quantum fields, which play crucial roles in our understanding of QFT in dS. However, the analytical computation of dS correlators is notoriously difficult, and significant progress has been...
Does the updated lepton non-universality parameter, given by LHCb in December 2022, imply that new physics in b to s window has faded way? In this work, we aim to answer this question by making global fits of Wilson coefficients in four different scenarios taking into account 196 observables in leptonic and semileptonic decays of B mesons and bottom baryons. We find that new physics...
In this presentation we would first introduce the basic idea of transversal momentum dependent ($k_T$) factorization theorem and its application in B meson decays, then we would show our recent calculation of charmless $B \to PP, PV, VV$ decay with including all the known next-to-leading-order QCD corrections, the $\pi K$ puzzle would also be mentioned.
The cosmological observations of cosmic microwave background and large-scale structure indicate that our universe has a nearly scaling invariant power spectrum of the primordial perturbation. However, the exact origin for this primordial spectrum is still unclear. We present a theoretical framework and several viable models to explain cosmic inflation and dark matter simultaneously, both are...
I will briefly go over the three approaches of particle physics studies with gravitational waves: early universe phase transitions, topological and non-topological solitons and environmental effects, and highlight some recent developments on the theory side and on experimental detection that we have made in each of the fields.
The Witten effect implies the presence of electric charge of magnetic monopole and possible relationship between axion and dyon. The axion-dyon dynamics can be reliably built based on the quantum electromagnetodynamics (QEMD) which was developed by Schwinger and Zwanziger in 1960’s. A generic low-energy axion-photon effective field theory can also be realized in the language of “generalized...
The hypothetical dark photon portal connecting the visible and dark sectors of the Universe has received considerable attention in recent years, with a focus on CP-conserving kinetic mixing between the Standard Model (SM) hypercharge gauge boson and a new U(1)$_X$ gauge boson. In the effective field theory context, one may write down non-renormalizable CP-violating kinetic mixing interactions...
We study the electromagnetic (EM) decays of $X(3823)$ as the $\psi_2(1^{3}D_{2})$ state by using the relativistic Bethe-Salpeter method. Our results are $\Gamma[X(3823)\rightarrow\chi_{_{c0}}\gamma]=1.2$ keV, $\Gamma[X(3823)\rightarrow\chi_{_{c1}}\gamma]=265$ keV, $\Gamma[X(3823)\rightarrow\chi_{_{c2}}\gamma]=57$ keV and $\Gamma[X(3823)\rightarrow\eta_{_c}\gamma]=1.3$ keV. The ratio ${\cal...
Momentum distributions of quarks/gluons inside a light baryon in a hard exclusive process are encoded in the light-cone distribution amplitudes (LCDAs). In this work, we point out that the leading twist LCDAs of a light baryon can be obtained through a simulation of a quasi-distribution amplitude calculable on lattice QCD within the framework of the large-momentum effective theory. We...
Gamma-ray bursts (GRBs) are classified into long and short populations (i.e., LGRBs and SGRBs) based on the observed bimodal distribution of duration T90. Multimessenger observations indicate that most SGRBs and LGRBs should be powered by ultrarelativistic jets launched from black hole (BH) hyperaccretion in compact-object mergers and massive collapsars, respectively. However, the duration...
As known neutrino oscillation is one the most important problems beyond standard model physics. Its observations enable us to infer that neutrinos have masses, although tiny. Another crucial problem within neutrino physics is the violation of Charge and Parity conservation, or namely CP violation. Here in our proposal we examine possible sensitivity on CP violating phase through oscillation...
Light sub-GeV halo dark matter (DM) particles up-scattered by high-energy cosmic-rays (CRs) (referred to as CRDM) can be energetic and become detectable by conventional DM direct detection experiments. We perform a refined analysis on the exclusion bounds of the spin-independent DM-nucleon scattering cross section $\sigma_{\chi p}$ in this approach. For the exclusion lower bounds, we determine...
We explore the potential of precision cosmological data to study non-minimal dark sectors by updating the cosmological constraint on the mirror twin Higgs model (MTH). The MTH model addresses the Higgs little hierarchy problem by introducing dark sector particles. In this work, we perform a Bayesian global analysis that includes the latest cosmic shear measurement from the DES three-year...
The direct detection of light dark matter (DM) is a big challenge. The kinetic energy of halo light DM is so small that the energy transfer through elastic scattering with nuclei can hardly exceed the detection threshold. In addition to using electron target, one possible way of overcoming this difficulty is fermionic DM absorption. Being converted to a massless neutrino, the light DM releases...
During cosmic inflation, massive particles can be spontaneously produced due to quantum fluctuations, leaving imprints in the correlator of (nearly) massless inflaton fluctuations. Information about physics at the inflation scale is then encoded in such inflation correlators and is hopefully recovered by future cosmic observations. However, our understanding of inflation correlators is very...
Various theories predict the existence of light scalar particles. When considering the finite temperature and density corrections to the scalar potential, scalar fields can be sourced by a variety of stellar objects and mediate additional long-range scalar forces. Since the scalar field is only sourced in certain environments, this provides a complementary way to probe the parameter space...
The vacuum stability problem is usually studied assuming that at zero temperature the universe is in the electroweak-breaking vacuum. This may not be the case, however, as seen by checking the evolution history of the early universe in theories beyond the Standard Model. In such models the transition to the electroweak-breaking vacuum may not be possible and/or the universe may have evolved...
With IceCube's discovery of an extragalactic diffuse neutrino flux and first identification of compelling evidence for corresponding sources, TXS0506+056 and NGC 1068, neutrino astronomy is at the tipping point for major breakthroughs. In this talk, I will give a brief overview on the current status of the nascent field of high-energy neutrino astronomy and then discuss the progress on the...
Insight-HXMT is China’s 1st X-ray astronomy satellite launched in 2017 and still working nominally in orbit. With its broad energy band (1-250 keV) and large effective area (about 400, 1000, 5000 cm^2 in three energy bands), it has been used to make many new discoveries with its observations on accreting X-ray pulsars, such as the highest energy cyclotron absorption features above 100 keV....
After obtaining black hole solutions in the bumblebee gravity theory, we put constraints on theory parameters with Solar system observations, black hole images, and extreme mass ratio inspirals.
Modular symmetry is a promising approach to address the flavor structure of Standard model. I shall present the recent development on modular symmetry in this talk.
If the temperature of the hot thermal plasma in the Early Universe was within a few orders of magnitude of the quantum gravity scale, then the hoop conjecture predicts the formation of microscopic black holes from particle collisions in the plasma. These black holes may evaporate and produce the dark matter relic abundance observed today for a wide variety of dark matter masses. We study the...
In this talk, I will discuss the test of lepton number violation beyond the approach of effective field theories. In the UV completion, one can study LNV interactions with neutrinoless double beta decay, collider searches and low energies precision experiments complementarily.
We go beyond the state-of-the-art by combining first principal lattice results and effective field theory approaches as Polyakov Loop model to explore the nonperturbative dark deconfinement-confinement phase transition and the generation of gravitational-waves in a dark Yang-Mills theory. We further include fermions with different representations in the dark sector. Employing the...
The delayed GeV−TeV cascade emission from extragalactic TeV−PeV sources are regarded as an ideal probe of the inter-galactic magnetic fields. Recently, LHAASO has detected ~10 TeV emission of the extraordinary powerful GRB 221009A within ~2000 s after the burst. Here we report the detection of a ~400 GeV photon, without accompanying prominent low-energy emission, by Fermi-LAT in the direction...
The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid scintillator detector currently being built in an underground laboratory in South China. The construction is expected to be completed by the end of 2023. JUNO will feature a remarkable energy resolution of 3% at 1 MeV, a large detector volume, and exceptional background control. With these advantages, JUNO will become a...
QCD aspects of exclusive heavy-hadron decays will be discussed with an emphasis on the perturbative factorization properties for the resulting hadronic matrix elements in the heavy quark expansion and on the systematic discussions of the distinct dynamical mechanisms governing the flavor-changing form factors beyond the leading-power approximation. Phenomenological implications of the...
In the past few years, several indirect hints for New Physics beyond the SM arose in precision measurements, e.g., $(g-2)_\mu$ and the W-boson mass. In this work, we consider a model containing new vector-like Fermion partner gauged under a new $U(1)'$ symmetry. It is found that the latest CDF $m_W$ measurement and $(g-2)_\mu$ can be simultaneously accommodated. We have also considered several...
强一阶电弱相变为解释正反物质不对称提供了必要条件，宇宙弦和畴壁是很多大统一等新物理模型的普遍预言。它们是太极和天琴计划、 脉冲星计时阵列等的重要科学目标之一。我将在此报告中跟大家交流一下粒子物理模型与早期宇宙对称性破缺，及相应的随机引力波产出与探测方面的研究进展。
We propose a novel scenario for dark matter (DM) in which weakly interacting massive particles (WIMPs) can freeze-in due to a first-order phase transition (FOPT) in the early Universe. The FOPT dilutes the preexisting DM density to zero, and leads to a sudden change in DM mass that prevents WIMPs from re-equilibrating due to their large mass-to-temperature ratio. Following the FOPT, WIMPs are...
We explore the possibility of explaining the W boson mass with an extra gauge boson mixing with the Z boson at tree level. Extra boson mixing with the Z boson will change the expression of the Z boson mass, thus altering the W boson mass. We explore two models in this work. We find that in the derivative portal dark matter model there are parameter spaces which can give the observed W boson...
Massive scalar field around a Kerr black hole can induce superradiant instabilities, resulting in the formation of a boson cloud around the black hole. Since rotating stellar-mass black holes are ubiquitous in every galaxy, the gravitational waves (GWs) emitted by their associated boson clouds together constitute a stochastic background on the sky, if cosmological dark matter consists of...
The Standard Model of particle physics has proven incredibly successful at describing many features of nature that we observe in our experiments. The Brout-Englert-Higgs mechanism that took place in the early Universe, less than a picosecond after the Big Bang, led to the electromagnetic and the weak interactions becoming distinct in their actions. In the SM, this mechanism introduces a...
In this talk, I introduce some recent developement in the construction of symbol letters of Feynman integrals using Baikov representations and intersection theory.
Dark SHINE is a new initiative to search for Dark Photon invisible decays into light dark matter particles utilizing the high repetition rate single electron beam to be deployed at the SHINE facility. This talk will show the Dark SHINE project in general and moreover the related BSM searches for Dark Photon at selected experiments at the energy and intensity frontiers.
A number of nuclear decay anomalies have been reported in the literature, which purport to show periodic variations in the decay rates of certain radioisotopes. If these reports reflect reality, they would necessitate a seismic shift in our understanding of fundamental physics. We provide the first mechanism to explain these findings, via the misalignment mechanism of QCD axion dark matter,...
The forward-backward asymmetry data for the bottom quark at LEP is in conflict with predictions from the standard model, and has been an unresolved issue for some time. It is important to address this discrepancy in order to conduct tests of both the standard model and any proposed theories beyond it. This presentation will provide an overview of recent efforts to investigate anomalous...
The search for primordial non-Gaussianity is an important probe of the early universe and can provide valuable information about the physics of inflation. I will discuss the possibility of measuring primordial non-Gaussianity through space-borne measurements of the cosmological gravitational wave background. We focus on the scalar non-Gaussianity generated during inflation, which can leave an...
The direct discovery of gravitational waves (GWs) from the coalescence of compact binary components by the LIGO/Virgo/KAGRA Collaboration provides an unprecedented opportunity for exploring the underlying theory of gravity. The gravitational waves, after their generation, will be propagating at cosmological distances before they are detected and can provide invaluable information on the...
Machine learning methods have proved powerful in particle physics, but without interpretability there is no guarantee the outcome of a learning algorithm is correct or robust. Thus the interpretable machine learning (IML) framework become necessary in the HEP large data era. I am demonstraintg how the IML framework can be achieved with detailed analysis on a few LHC processes as example, and...
大统一理论旨在统一电磁、强和弱三种基本相互作用。其经典预言是质子衰变。目前尚未发现质子衰变的迹象，这对大统一能标带来较强的限制。在SO(10)大统一理论中，由于标准模型费米子都是安排在一个不可约表示下，夸克和轻子的质量与味混合是相互关联的。伴随着中微子实验进入精确测量时代，来自费米子味混合的实验数据对大统一的限制开始逐渐被慎重对待。此外，SO(10)大统一模型还可以产生宇宙弦并辐射出引力波，这使得我们还可以从宇宙学观测的角度去认识大统一理论。我将讨论上面提及的不同类型的实验限制，并给出目前符合所有实验数据的大统一模型。
In this work, by using machine learning methods, we study the sensitivities of heavy pseudo-Dirac neutrino $N$ in the inverse seesaw at the high-energy hadron colliders. The production process for the signal is $pp \to \ell^\pm N \to 3 \ell + E_T^{\rm miss}$, while the dominant background is $p p \to W^\pm Z \to 3 \ell + E_T^{\rm miss}$. We use either the Multi-Layer Perceptron or the Boosted...
The Galactic center gamma-ray excess (GCE) is a long-standing unsolved problem. One of candidate solutions, the dark matter (DM) annihilation, has been recently tested with other astrophysical observations, such as AMS-02 electron-positron spectra, Fermi Dwarf spheroidal galaxies gamma-ray data, and so on. By assuming that the DM particles annihilate purely into a normal charged fermion pair,...
Extreme mass ratio inspirals (EMRIs) are among the
most promising sources for space-based gravitational wave detectors. For EMRIs, the small compact object spends the last few years inspiralling deep inside the strong gravitational field around the massive BH with a highly relativistic speed. The emitted GWs from EMRI/IMRI encode rich information about the spacetime geometry around the MBH...
Due to the large excursion of the inflaton field. The parameters, such as mass and couplings of the fields coupled to the inflaton field, may change dastically during inflation. And thus phase transitions may be induced. In this talk, I am going to discuss the gravitational wave signals produced by phase transitions during inflation. For first-order phase transitions, I will show that the...
We systematically discuss the deep connection between TianQin and the fundamental problems in particles cosmology, including the gravitational wave detection of dark matter, electroweak baryogenesis and so on.
暗物质与夸克物质是两类极端物态，前者的物理本质尚不清楚，后者是否能够在中子星内部存在也是一个前沿科学问题。报告中我将介绍近几年暗物质间接探测的相关研究进展，对一些候选疑似信号进行重点讨论；我还将介绍现阶段基于多信使数据的中子星物态方程的研究，特别是关于最重的中子星内部存在夸克物质的可能性。
The $\tau$ lepton is the only known lepton massive enough to decay into hadrons. Besides serving as a clean laboratory for studying various low-energy aspects of the strong interactions, the hadronic $\tau$ decays may also allow us to explore CP-violating effects both within and beyond the SM. In this talk, I will discuss the CP asymmetries in $\tau \to K_S \pi \nu_\tau$ decays, which arise...
High-frequency gravitational waves (HFGWs) carry a wealth of information on the early Universe with a tiny comoving Hubble horizon and astronomical objects of small scale but with dense energy. We demonstrate that the nearby planets, such as Earth and Jupiter, can be utilized as a laboratory for detecting the HFGWs. These GWs are then expected to convert to signal photons in the planetary...
Hydrogen atoms in the universe emit radiation at a wavelength of 21 cm in the radio band, making the 21-cm radiation a powerful tool for exploring the cosmos. 21-cm line observations open a new window for cosmological investigations. By utilizing the 21-cm signal, we can probe the entire evolutionary history of the universe after the recombination epoch and perform a tomographic exploration...
