2nd Topics of Particle, Astro and Cosmo Frontiers (TOPAC 2024)

30 May 2024, 00:00 → 2 Jun 2024, 22:50 Asia/Shanghai

Southeast University (Sipailou Campus)

第二届粒子物理、天体物理和宇宙学前沿课题研讨会（2nd TOPAC: Topics of Particle, Astro and Cosmo Frontiers）将于2024年5月31日至6月2日在东南大学四牌楼校区举办。

前所未有的高能对撞数据、更高精度的粒子物理测量、不断升级的天文和宇宙学观测、迅速积累的引力波观测将我们带入了一个前所未有的境地：在粒子物理、天体物理和宇宙学的交叉领域不断涌现新的研究课题和热点，这也正逐渐加深我们对粒子物理、天文观测和早期宇宙的理解和认识。本会议将为相关领域专家提供一个相互交流的平台，深入探讨目前的研究现状和未来的可能方向，促进国内相关研究领域的发展。本次会议将涉及味物理，中微子、暗物质，天体物理、宇宙学、引力波等多个主题。

本次会议除口头报告外，还将提供海报展示的机会，欢迎大家提交口头报告和海报摘要、并积极参会。

TOPAC第一届会议于2023年在上海交通大学李政道研究所举办；本次是TOPAC会议的第二届，由东南大学主办，北京大学、上海交通大学协办。举办地在南京。

特别致谢：感谢东南大学艺术学院的尹文教授授权我们免费使用其艺术作品，用于制作本次会议的海报胸牌等物品。
 

会议有关事项：
 

会议时间：

2024年5月30日：报到

2024年5月31日至6月2日：线下报告

2024年6月3日：离会

 

会议注册：

网上注册截止日期：2024年4月15日

会议网址：https://indico-tdli.sjtu.edu.cn/e/TOPAC2024

 

会议注册费：

教师：1500元
学生和博士后：1000元

 

组织委员会（拼音顺序）：

葛韶锋（上海交通大学）

何小刚（上海交通大学）

邵立晶（北京大学）

张永超（东南大学，大会主席）
 

会务秘书：

卢月 
电话：15365073402 
邮箱：2238854008@qq.com

 

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The 2nd TOPAC (Topics of Particle, Astro and Cosmo Frontiers) will be held on May 30 – June 2, 2024 at the Sipailou Campus of Southeast University  in Nanjing.

 

Unprecedented amount of high-energy collision data, higher precision measurements of particle physics experiments, upgrading astrophysical and cosmological observations, and quickly increasing gravitational wave measurements are bringing us into a new territory to be explored. Interdisciplinary research topics and highlights keep emerging across particle physics, astrophysics, and cosmology, which is enhancing our understanding of elementary particles, astrophysical observations, and the early university. This TOPAC meeting will provide a platform for experts in different fields to interact with each other to deeply discuss the current status and possible future directions. Hopefully this would push the development of involved directions. This TOPAC meeting covers multiple topics including flavor, neutrino, dark matter, astrophysics, cosmology, and gravitational wave.

 

In addition to the oral talks, this TOPAC meeting would also provide poster presentations. Abstracts for oral talks and poster presentations are highly welcome. You are welcome to register and participate the TOPAC meeting.

 

The 1^st TOPAC meeting was held at Tsung-Dao Lee Institute, Shanghai Jiao Tong University in 2023. The 2^nd TOPAC meeting this year would be hosted by the Southeast University and assisted by Peking University and Shanghai Jiao Tong University. 

 

Conference Items:

 

1. Conference Dates:

May 30, 2024: Arrival

May 30 – June 2, 2024: Onsite talks

June 3, 2024: Departure

 

2. Registration:

Deadline: April 30, 2024

Indico: https://indico-tdli.sjtu.edu.cn/e/TOPAC2024

 

 

3. Registration fee:

Professors: CNY 1500
Students & Postdocs: CNY 1000
 

4. Organization Committee:

Shao-Feng Ge (Shanghai Jiao Tong University)

Xiao-Gang He (Shanghai Jiao Tong University)

Lijing Shao (Peking University)

Yongchao Zhang (Southeast University, Chair)

 

5. Secretary

Yue Lu

Cellphone: 15365073402 
Email: 2238854008@qq.com

 

 

certificate.pdf

meeting-notice.pdf

Thursday, 30 May

14:00 → 20:00 Registration

Friday, 31 May

08:15 → 08:30 Opening

08:30 → 10:10 Flavor

Convener: Shu Li (TDLI, SJTU)

08:30 Charm Physics at BES III

Speaker: Haibo Li

HailongMa_2024_IHEP_v2.pptx

08:55 Recent results from Belle II

Speaker: Sen Jia

Belle2.pdf

09:20 SRF Cavity Searches for Dark Photon Dark Matter

Speaker: Jing Shu

TOPAC2024.pdf

09:45 BSM physics at ATLAS

Speaker: Prof. Lei Zhang (Nanjing University (CN))

20240531Topac_NewPhysATLAS-v3.pdf

10:10 → 10:45 Break: photo and coffee

10:45 → 12:00 Astrophysics

Convener: Huan Yang (Perimeter Institute & University of Guelph)

10:45 Dynamic Universe: A FAST Perspective

Speaker: DI LI (National Astronomical Observatories, CAS)

frb24-topac.pptx

11:10 Binary Neutron Stars: Electromagnetic and Gravitational Wave Binaries, and Kilonovae

Speaker: Youjun Lu

BNSs.pptx

11:35 Detecting Elastic Coherent Neutrino Scattering with RELICS Experiment

The Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) was predicted in 1974 but wasn't experimentally confirmed until 2017 due to its extremely low energy deposit, making detection challenging due to energy threshold and background levels. Liquid Xenon Time Projection Chambers (LXeTPCs) have shown excellence in dark matter searches and may serve as an ideal technology for detecting CEvNS. The RELICS experiment aims to utilize LXeTPC to detect reactor neutrinos via CEνNS. This report will cover the latest advancements in CEvNS detection.

Speaker: Shengchao Li (西湖大学 Westlake University)

Nanjing_shengchao.pdf

12:00 → 13:30 Lunch

13:30 → 15:10 Astrophysics

Convener: Sichun Sun (Beijing Institute of Technology)

13:30 Constraining Bosonic Dark Matter-Baryon Interactions from Neutron Star Collapse

Dark matter (DM) may be captured around a neutron star (NS) through DM-nucleon interactions. We observe that the enhancement of such capturing is particularly significant when DM-nucleon scattering cross-section depends on the relative velocity and/or momentum transfer. This increment could potentially lead to the formation of a black hole within the typical lifetime of the NS. As the black hole grows through the accretion of matter from the NS, it ultimately results in the collapse of the host. Utilizing the existing pulsar data J0437-4715 and J2124-3858, we derive the stringent constraints on the DM-nucleon scattering cross-section across a broad range of DM masses.

Speaker: Dr Arvind Kumar Mishra (Nanjing Normal University, Nanjing, China)

13:55 Imprints of Dissipative Effects in Phase Transition Gravitational Waves

Speaker: Huai-Ke Guo

Huaike-Guo-TOPAC2024.pdf

14:20 Gravitational waves from the sound of first-order phase transition

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 to revealing many unresolved puzzles in our universe. 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 the sound wave mechanism. I will use a benchmark model to demonstrate the procedures of this framework and show the corresponding results.

Speaker: Dr Xiao Wang (Monash University)

14:45 Light Thermal Dark Matter Beyond p-Wave Annihilation in Minimal Higgs Portal Model

Speaker: Yue-Lin Sming Tsai (Purple Mountain Observatory)

MeV_DM_25mins.pdf

13:30 → 15:10 Higgs

Convener: Zhuoni Qian (Hangzhou Normal University)

13:30 Dark photon effects with the kinetic and mass mixing in Z boson decay processes

Motivated by the most recent measurement of tau polarization in $Z\to \tau^+\tau^-$ by CMS, we have introduced a new $U(1)_X$ gauge boson field X, which can have renormalizable kinetic mixing with the standard model $U(1)_Y$ gauge boson field Y.
In addition to the kinetic mixing of the dark photon, denoted as $\sigma$, there may also be mass mixing introduced by the additional Higgs doublet with a vacuum expectation value (vev) participating in $U(1)_X$ and electroweak symmetry breaking simultaneously.
The interaction of the Z boson with the SM leptons is modified by the introduction of the mixing ratio parameter $\epsilon$, which quantifies the magnitude of both the mass and kinetic mixing of the dark photon.
Initially, we use the tau lepton as an example to explore the Z boson phenomenology of the dark photon model with both kinetic and mass mixing. The goal is to determine the allowed parameter regions by taking into account constraints from the vector and axial-vector couplings $g_{V,A}^\tau$, the decay branching ratio $Br(Z\to \tau^- \tau^+)$ and tau lepton polarization in $Z\to \tau^-\tau^+$. We found that the mixing ratio plays important role in the Z boson features by choosing different $\epsilon$ values.
Furthermore, we aim to generalize our analysis from the tau-lepton case to include all fermions by conducting global fits. This allows us to identify viable regions by incorporating relevant fermion constraints and the W/Z mass ratio.
Correspondingly, we obtain the fit results with the kinetic mixing parameter $\sigma=0.074\pm0.021$, mixing ratio $\epsilon=-1.37\pm0.46$, and dark photon mass $m_X=275\pm39$ GeV. Our global analysis indicates a preference for a dark photon mass larger than $m_Z$.

Speaker: Jin Sun (Institute for Basic Science (IBS))

Jin Sun-DP.pdf

13:55 long-lived particle search

The ForwArd Search ExpeRiment (FASER,), is a recently installed detector at the LHC that can detect light, long lived particles. In this work we study the prospect of detecting light CP-even and CP-odd scalars at the FASER. We develop the general formalism for the scalar production and decay from mesons at LHC, given modified couplings of the scalars to the SM particles, as well as summarizing the relevant GeV-scale experiment constraints. We then analyze the reaches of light scalars in the large $\tan\beta$ region of the Type-I 2HDM, in which a light scalar with relatively long life time could be accommodated.

Speaker: Wei Su (SYSU)

2nd TOPAC -WeiSu.pdf

14:20 GKZ hypergeometric systems of four-loop vacuum Feynman integrals

We present GKZ hypergeometric systems of four-loop vacuum Feynman integrals.

Speaker: Prof. Hai-Bin Zhang (Hebei University)

4-loop vacuum.pdf

14:45 Higgs properties and new physics beyond the SM

The discovery of the Higgs boson at the Large Hadron Collider (LHC) has opened a new era in particle physics.
Precise measurements of the properties of the Higgs boson are crucial for addressing several fundamental questions
in the field. These include understanding the mechanism behind electroweak symmetry breaking,
unraveling the origin of particle masses, and exploring potential sources of CP violation
that could explain the matter-antimatter asymmetry in the universe, and so on.
In this talk, I will provide an overview of the recent advancements in Higgs physics,
both within the framework of the Standard Model (SM) and beyond.
By examining the latest research, we will gain insights into the properties and behavior of the Higgs boson,
shedding light on the fundamental workings of the universe.

Speaker: Prof. Bin Yan (IHEP)

Higgs_BY.pdf

15:10 → 15:30 Break: coffee

15:30 → 17:10 Experiments

Convener: Prof. Bin Yan (IHEP)

15:30 Recent ATLAS results of Dark Matter and Dark Photon combinations and Dark Higgs searches

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 collision data at a centre-of-mass energy $\sqrt{s}$ = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider between 2015-2018. The results from three of the most sensitive searches are combined statistically. These searches target signatures with large EmissT and a leptonically decaying Z boson; large $E^{miss}_T$ and a Higgs boson decaying to bottom quarks; and production of charged Higgs bosons in final states with top and bottom quarks, respectively. Constraints are derived for several common as well as new benchmark scenarios within the 2HDM+a.

Ref. ATLAS-CONF-2024-004
A first dedicated search is performed for dark matter particles produced in association with a resonantly produced pair of b-quarks with m(bb) < 150 GeV using 140 fb$^{-1}$ of proton-proton collisions recorded by the ATLAS detector at a center-of-mass energy of 13 TeV. This signature is expected in extensions of the Standard Model predicting the production of dark matter particles, in particular those containing dark Higgs bosons. This search uses a novel experimental method to extend the experimental reach to lower bb-pair invariant masses, considers a wider range of dark Higgs boson interpretations and excludes new regions of parameter space for this model. For dark Higgs boson masses between 30 and 150 GeV, Z′ mediator masses up to 3.4 TeV and 4.8 TeV are excluded for benchmark scenarios.

Speaker: Shu Li (TDLI, SJTU)

ATLAS-DM-TOPAC2024.pptx

15:55 New physics probed with off-Z-pole data

We fully explore the prospect of using the off $Z$-pole run at
future lepton colliders to probe the new physics (NP) beyond the Standard Model (SM) via dimension-6 four-fermion effective operators. With interference between the dimesion-6 operator and SM diagram contributions to the $e^+ e^- \rightarrow f \bar f$ scattering processes, the NP effects shows up at collision energy
off of the $Z$ pole. The $Z$ line shape scan is thus useful not just for the $Z$ mass and width measurements, but
also for NP probes. I will discuss the key observable and uncertainties involved in order to reach a realistic prospects for the reach.

Speaker: Zhuoni Qian (Hangzhou Normal University)

qian-nanjing202405.pdf

16:20 Search for T-odd mechanisms beyond the standard model in transversely polarized pe⃗ elastic scattering?

Within the standard model, transverse single spin asymmetries in electron elastic scatterings can only arise from multi-photon exchanges. The A4@MAMI collaboration has measured the beam transverse single spin asymmetry in electron-proton elastic scattering from 315 to 1508 MeV (Phys. Rev. Lett. 124, 122003 (2020)). The data are significantly different from theoretical calculations based on chiral perturbation (Phys. Rev. C 70, 054003 (2004)), unitarity (Phys. Rev. C 70, 045206 (2004)) and optical theorem (Phys. Rev. C 73, 055201 (2006)). Comparing with the unitary calculation, one may attribute the discrepancy to heavier intermediate states in two-photon exchanges (TPE) which are not included in the calculation. On the other hand, it requires the virtual photon to have large energy to excite high-energy/heavy states, one would expect contributions due to these intermediate states are small. From this point of view, the discrepancy is puzzling. Similar discrepancies were also observed at other laboratories, in both electron-proton and electron-lead scatterings, such as SAMPLE at MIT-Bates (Phys. Rev. C 63, 064001 (2001)), Qweak at JLab (Phys. Rev. Lett. 125 112502 (2020)) and PREX-II at JLab (Phys. Rev. Lett. 128, 142501 (2022)).

Another possible origin of these discrepancies could be T-odd mechanisms beyond the standard model, such as a novel T-violating interaction or an unanticipated two-boson exchange involving one virtual photon and one unknown T-conserving boson. However, the hadronic/nuclear uncertainties (such as possible intermediate states in TPE) in the theoretical calculations hamper us from investigating new physics via the transverse single spin asymmetry. In view of this, we propose to measure the transverse spin asymmetry in proton-electron (pe⃗) scattering instead of electron-proton (e⃗ p) scattering using an unpolarized proton beam and polarized electrons in a polarized hydrogen gas target, which is planned at the hadronic accelerator HIAF, currently under construction at IMP, CAS. In pe scatterings, the effective energy (or Q2) is 2∼3 orders smaller than in ep scattering, only elastic intermediate state (i.e., proton) will be involved in two-photon exchanges. As a result, theory based on unitarity can provide calculations with little theoretical uncertainties. In experiments with polarized electron beams, asymmetries are usually very small due to relativistic effects. In scatterings between an unpolarized proton beam and a polarized electron target, no such effects present, as a result, the asymmetry will be larger by 4 orders, compared with e⃗ p experiments with electron beams of 1∼2 GeV. Consequently, systematical errors in the experiment will be reduced significantly. Given the above advantages, the transversely polarized pe⃗ scattering could be an attractive approach to search for new physics.

Speaker: Boxing Gou (IMP, CAS)

TOPAC2024_Gou.pdf

15:30 → 17:10 Neutrino

Convener: Chengcheng Han (Sun Yat-sen university)

15:30 Predictions of m_ee and neutrino mass from a consistent Froggatt-Nielsen model

The seesaw mechanism is the most attractive mechanism to explain the small neutrino masses, which predicts the neutrinoless double beta decay (0νββ) of the nucleus. Thus the discovery of 0νββ is extremely important for future particle physics. However, the present data on the neutrino oscillation is not sufficient to predict the value of $m_{ee}$ as well as the neutrino mass $m^i_ν$. In this talk, by adopting a simple and consistent Froggatt-Nielsen model, which can well explain the observed masses and mixing angles of quark and lepton sectors, we calculate the distribution of $m_{ee}$ and $m^i_ν$. Interestingly, a relatively large part of the preferred parameter space can be detected in the near future.

Speaker: Prof. Jin-Wei Wang (UESTC)

FN.pdf

15:55 Joint Study of Anomalous Magnetic Moment of Muon and Mechanism of Neutrino Mass Generation

Speaker: Pei-Wen Wu

吴培文-TOPAC2024.pptx

16:20 SMEFT vs HEFT in the case of type-II seesaw

The representative effective field theories(EFTs) written in terms of Standard Model particles are Standard Model EFT(SMEFT) and Higgs EFT(HEFT). When we integrate out the heavy particles in the UV theory before electroweak symmetry breaking, it results in the SMEFT. On the other hand, if we integrate out the heavy particles taking into account the mass mixing in the symmetry-breaking phase, it results in the HEFT. Recently, the matching type-I, II, and III seesaw onto the SMEFT has been studied by the IHEP group and attracted a lot of attention. We have matched the type-II seesaw model onto the HEFT and compared our results with those of previous studies. We show quantitatively how much more accurate the HEFT description is than the SMEFT when the mass scale of the heavy particles is close to the electroweak scale.

Speaker: Yoshiki Uchida (South China Normal University)

YoshikiUchida_20240531_v2.pdf

17:30 → 20:00 Poster session and dinner

17:30 Aiming for Tops of ALPs with a Muon Collider

Future muon colliders with center-of-mass energy of $\mathcal{O}(1-10)$ TeV can provide a clean high-energy environment with advantages in searches for TeV-scale axion-like particles (ALPs), pseudo-Nambu–Goldstone bosons associated with spontaneously broken global symmetries, which are widely predicted in physics beyond the Standard Model (SM). We exploit ALP couplings to SM fermions, and guided by unitarity constraints, build a search strategy focusing on the ALP decay to top quark pairs at muon colliders. It is found that a large parameter space of TeV-scale ALPs with TeV-scale decay constants can be probed by utilizing the ALP-top quark coupling.

Speaker: Yufei Zhang

17:35 Axion star condensation around primordial black holes and microlensing limits

Dark matter is one of the biggest mysteries in physics and astronomy today. While multiple dark matter candidates have been proposed, such as the axion and primordial black holes (PBHs), the interplay between them is not well understood. In this talk, I will focus on the formation of axion minihalos around PBHs and the condensation of axion stars inside them, and reveal distinct morphological characteristics of these structures compared to isolated axion star scenarios. Furthermore, I will explore the implications of these results when applied to gravitational microlensing from extended objects, providing constraints on the fraction of these objects contributing to microlensing events from the EROS-2 survey.

Speaker: 孜文 尹 (上海交通大学物理与天文学院（李政道研究所）)

17:40 Future targets for light gauge bosons from cosmic strings

Cosmic strings, theoretical one-dimensional topological defects from the early universe, are a compelling source for studying dark matter production and gravitational wave (GW) emission. In this talk, I will focus on the production of gauge bosons and GW emission resulting from the decay of cosmic strings, discussing the constraints imposed by cosmological considerations. Specifically, I will examine the contribution of gauge bosons radiated from strings to dark matter and dark radiation respectively, which are strictly limited by the observed dark matter abundance and Cosmic Microwave Background data respectively. Moreover, I will assess the GW spectrum of this model against the forecasted capabilities of future GW observatories, with a particular emphasis on the Laser Interferometer Space Antenna. Following that, I will provide an overview of how these considerations influence the model parameters, specifically the gauge boson mass and the energy scale of U(1) symmetry breaking, offering insights into the potential for cosmic strings to inform our understanding of dark matter and GW astronomy.

Speaker: Hanyu Cheng (Tsung-Dao Lee Institute & SJTU)

17:45 Wide Binary Evaporation by Dark Solitons

We perform an analytic calculation of binary star evaporation rate under the gravitational potential from spatially extended dark solitons, and demonstrate that Milky Way’s wide binary star systems are susceptible to tidal perturbations from dark matter solitons of comparable and larger sizes. The GAIA data shows a sharp decrease of halo-like wide binaries at large separations, indicating possible disruptions by dark solitons. We further put constraints on the mass and radius of solitons, which may correspond to ultralight bosonic dark matter around $10^{-15}\,\rm eV$.

Speaker: Zihang Wang (Institute of High Energy Physics)

17:50 The SM expected branching ratio for h→γγ and an excess for h→Zγ

Combination of recent measurements for $h \to Z \gamma$ from ALTLAS and CMS shows an excess that the ratio of the observed and standard model (SM) predicted branching ratios $\mu = (\sigma\cdot{\cal B})_{\mathrm{obs}}/(\sigma\cdot{\cal B})_{\mathrm{SM}}$ is $2.2\pm 0.7$. If confirmed, it is a signal of new physics (NP) beyond SM. We study NP explanation for this excess. In general, for a given model it also affects the process $h \to \gamma \gamma$. Since measured branching ratio for this process agrees with SM prediction well, the model is constrained severely. We find that a minimally fermion singlets and doublet extended NP model can explain simultaneously the current data for $h \to Z \gamma$ and $h\to \gamma\gamma$. There are two solutions. One is the SM amplitude $c_Z^{\text{SM}}$ is enhanced by $\delta c_Z$ for $h \to Z \gamma$ to the observed value, but the $h \to \gamma \gamma$ amplitude $c_\gamma^{\text{SM}} +\delta c_\gamma$ is decreased to $-c_\gamma^{\text{SM}}$ to give the observed branching ratio. This seems to be a contrived solution that although cannot be ruled out simply using branching ratio measurements. We, however, find another solution which naturally enhances the $h \to Z \gamma$ to the measured value, but keeps the $h \to \gamma\gamma$ close to its SM prediction. We also comment on some phenomenology of these new fermions.

Speaker: Zhonglv Huang (TDLI)

17:55 The neutral scalars of 2HDM+S model under the LHC

The 2HDM+S is the singlet extension of 2HDM, which can accommodate more physics potential beyond the SM. We summarize the type II 2HDM+S model with various Higgs potential structures, and discuss several scenarios with different mass hierarchy. In this study, we concentrate on the mass eigenstate of the 2HDM+S, and test the parameter space of Higgs mixing angles and masses against the experimental constraints, including 125 GeV Higgs measurements, BSM Higgs direct searches, $STU$ and $B$-physics observables. In particular, we study the exotic channels of $h_{125}\rightarrow A_S A_S$ and $h_{125}\rightarrow h_S h_S$ decays for the light singlet-like Higgs scenarios $m_{h_S/A_S} < 62.5$ GeV, and determine the limit of Higgs mixing angles. Furthermore, we study the phenomenological distinction between 2HDM+S and 2HDM, and explore the indirect impact of the singlet admixture on the parameter space of $\cos(\beta-\alpha_1)$, $\tan\beta$ and $m_A$.

Speaker: Cheng Li (Sun-Yat-Sen University)

18:00 Detecting Quadratically Coupled Ultra-light Dark Matter with Stimulated Annihilation

Ultra-light Dark Matter (ULDM) is one of the most promising DM candidates. Due to the Bose
enhancement, we find the annihilation rate of the ULDM in the presence of background photon
radiation can be greatly enhanced and produce a distinctive reflected electromagnetic wave with an
angular frequency equal to the ULDM mass. We propose to utilize such stimulated annihilation
to probe the ULDM with the electromagnetic quadratic coupling by emitting a beam of radio into
space. With a power of 50 MW emitter, we forecast the sensitivity of quadratic coupling in different
local halo models for low-frequency radio telescopes, such as LOFAR, UTR-2 and ngLOBO.

Speaker: Yuanlin Gong (Nanjing Normal University)

Poster-Yuanlin Gong-龚远林.pdf

18:05 The revelation of the nature of the inertial force and its physical impacts

Speaker: Chiyi Chen

18:10 Prospects for testing gravity with pulsars around Sagittarius A*

Future observation with next-generation large-area radio telescopes are expected to discover radio pulsars closely orbiting around Sagittarius A (Sgr A), the supermassive black hole (SMBH) in our Galactic Center (GC). Such a system can provide a unique laboratory for testing gravity theories , as well as the astrophysics around the GC. We will introduce our recent studies about prospects for using the SMBH-pulsar system to test gravity. Including testing the no-hair theorem in General Relativity, constraining the vector charge of Sgr A, probing the small-scale dark matter distribution around Sgr A and so on.

Speaker: Zexin Hu (Peking University)

18:15 Dynamic instability analysis for bumblebee black holes: the odd parity

Spherical black-hole (BH) solutions have been found in the bumblebee gravity where a vector field nonminimally couples to the Ricci tensor. We study dynamic (in)stability associated with the gravitational and vector perturbations of odd parity against these bumblebee BHs. Under the plane-wave approximation, we find that bumblebee BHs do not suffer ghost instability, but gradient instability and tachyonic instability exist when the bumblebee charge exceeds certain values. The existence of the instabilities also depends on the nonminimal coupling constant $\xi$ that, there is a minimal value $\xi \sim 4\pi G$ with $G$ the gravitational constant for the instabilities to happen.
The theoretical consideration for bumblebee BH stability turns out to place stronger constraints on the parameter space than those from the recent observations of supermassive BH shadows by the Event Horizon Telescope Collaboration. It is also reminiscent of Penrose's cosmic censorship conjecture since the charge of bumblebee BHs cannot be too large due to the dynamic instabilities. Specifically, for $\xi(\xi-16\pi G) > 0$, we find that the charge of a bumblebee BH cannot be larger than its mass.

Speaker: ZHANFENG MAI (Kavli Institute for Astronomy and Astrophysics， Peking University)

18:20 Illuminating Black Hole Shadow with Annihilating Dark Matter

Speaker: Yuxin Liu

18:25 Weak Lensing Constraints on Dark Matter-Baryon Interactions with N-Body Simulations and Machine Learning

We investigate the elastic scattering cross section between dark matter and protons using the DES Year 3 weak lensing data. This scattering induces a dark acoustic oscillation structure in the matter power spectra. To address non-linear effects at low redshift, we utilize principal component analysis alongside a limited set of N-body simulations, improving the reliability of our matter power spectrum prediction. We further perform a robust Markov Chain Monte Carlo analysis to derive the upper bounds on the DM-proton elastic scattering cross-section, assuming different velocity dependencies. Our results, presented as the first Frequentist upper limits, are compared with the ones obtained by Bayesian approach. Compared with the upper limits derived from the Planck cosmic microwave background data, our findings from DES Year 3 data exhibit improvements of up to a factor of five. In addition, we forecast the future sensitivities of the China Space Station Telescope, the upcoming capabilities of this telescope could improve the current limits by approximately one order of magnitude.

Speaker: 弛 张 (中国科学院紫金山天文台)

18:30 Degeneracy Enhancement of Neutron-Antineutron Oscillation in Neutron Star

We explore the theoretical description of oscillations in degenerate cases, presenting the formula for oscillation probability with neutrino oscillation as an illustrative example. We then apply the degenerate oscillation theory to study neutron-antineutron oscillations, calculating the constraints of the new model on oscillation parameters, such as mixing angles, in neutron stars. Our findings provide valuable insights into the behavior of particle oscillations in extremely degenerate environments, offering strong constraints on neutron-antineutron mixing, and further restrict the choice of GUT models.

Speakers: Qiheng Wang, Xuanye Fu (Shanghai Jiao Tong University), Ziyang Guo

18:35 Searching for heavy neutral lepton and LNV through VBS at muon colliders

High-energy muon collider can play as an emitter of electroweak gauge bosons and thus leads to substantial vector boson scattering (VBS) processes. In this work, we investigate the production of heavy neutral lepton (HNL) $N$ and lepton number violation (LNV) signature through VBS at high-energy muon colliders. They provide clean and robust LNV signatures to tell the nature of Majorana HNLs and thus have more advantageous benefits than direct $\mu\mu$ annihilation. We analyze the potential of searching for Majorana HNL and obtain the exclusion limits on mixing $V_{\ell N}$ . Based on this same-sign lepton signature, we also obtain the sensitivity of muon collider to the Weinberg operator.

Speaker: Dr Man Yuan (Nankai University)

TOPAC2024-poster-袁满.pdf

18:40 Neutron star cooling with lepton-flavor-violating axions

The cores of dense stars are a powerful laboratory for studying feebly-coupled particles such as axions. Some of the strongest constraints on axionlike particles and their couplings to ordinary matter derive from considerations of stellar axion emission. In this work we study the radiation of axionlike particles from degenerate neutron star matter via a lepton-flavor-violating coupling that leads to muon-electron conversion when an axion is emitted. We calculate the axion emission rate per unit volume (emissivity) and by comparing with the rate of neutrino emission, we infer upper limits on the lepton-flavor-violating coupling $|g_{ae\mu}|$ that are at the level of $10^{-6}$. For the hotter environment of a supernova, such as SN 1987A, the axion emission rate is enhanced and the limit is stronger, at the level of $10^{-11}$, competitive with laboratory limits. Interestingly, our derivation of the axion emissivity reveals that axion emission via the lepton-flavor-violating coupling is suppressed relative to the familiar lepton-flavor-preserving channels by the square of the plasma temperature to muon mass ratio, which is responsible for the relatively weaker limits.

Speaker: Hong-Yi Zhang

18:45 A mechanism relating the fermionic mass hierarchy to the flavor mixing

Considering the hierarchical structure of fermionic masses and the fermionic flavor mixing puzzles in the Standard Model, we propose to relate them by the see-saw mechanism, i.e. only the third generation of quarks and charged leptons achieve the masses at the tree level, the first two generations achieves masses through the mixings with the third generation, and the neutrinos achieve tiny Majorana masses by the so-called Type-I see-saw mechanism. This new picture at the fermion sector can explain simultaneously the flavor mixing puzzle and mass hierarchy puzzle in the SM. In addition, a flavor-dependent model (FDM) is proposed to realize the new mechanism, and observing the top quark rare decay processes $t\to ch$, $t\to uh$ and the lepton flavor violation processes $\mu\to3e,\;\tau\to3e,\;\mu\to3\mu$ is effective to test the proposed FDM.

Speaker: jinlei yang (Hebei University)

18:50 Spontaneous CP violation in Supersymmetric QCD

Speaker: 耀铎 王

18:55 The electroweak magnetic monopole in the presence of KSVZ axion

The Witten effect implies the dynamics of axion and magnetic monopole. The Cho-Maison monopole is a realistic electroweak monopole arisen in the Weinberg-Salam theory. This monopole of TeV scale mass motivates the dedicated search for electroweak monopole at colliders. In this work we investigate the implication of KSVZ axion to the electroweak magnetic monopole. We use the spherically symmetric ansatz for the electroweak dyon and introduce the spherically symmetric function for the axion field. The effective Lagrangian is then shown in terms of the electroweak monopole part, the axion kinetic energy as well as the axion interaction term. We derive the consequent equations of motion in the presence of the axion-photon coupling and show the numerical results of the topological solutions. We then calculate the changed characteristics of the electroweak monopole such as the monopole mass and the electromagnetic charges, as well as the axion potential energy.

Speaker: Rui-jia Zhang (Nankai University)

19:00 Cosmologically Consistent Analysis of Gravitational Waves from Hidden Sectors under Synchronous Thermal Evolution

In this talk, we will discuss production of gravitational waves in the early universe within a first order phase transition involving a hidden sector feebly coupled with the visible sector. Unlike most existing studies on GWs from hidden sectors, which assume a constant temperature ratio between the hidden and visible sectors (i.e., ξ=T_h/T=const), we adopt a more precise approach using synchronous thermal evolution, denoted as ξ(T). We will discuss in detail how to obtain this ξ(T) and how it will influence our analysis on GWs from hidden sectors. As a result, we find that the two-field model predicts gravitational waves accessible at several proposed gravitational wave detectors: LISA, DECIGO, BBO, Taiji and their discovery would probe specific regions of the hidden sector parameter space and may also shed light on the nature of bubble nucleation in the early universe.

Speaker: Jinzheng Li (Northeastern University (Boston))

Saturday, 1 June

08:30 → 10:10 DM

Convener: Hong-Hao Zhang

08:30 Dark matter search results in PandaX-4T experiment

PandaX-4T experiment is a dark matter direct detection experiment that employs a dual-phase time projection chamber with a sensitive volume containing 3.7 tonnes of liquid xenon. Since 2020, the PandaX-4T experiment has finished the data taking of run0 and run1 which has been used to test several dark matter models. In this talk, we will discuss the latest dark matter search results of the PandaX-4T experiment.

Speaker: 帅杰 李 (Yalong Hydro)

南京0601_TOPAC2024_LSJ_v1.pptx

08:55 Levitodynamics with multi-stochastic forces and the simple applications on the dark matter detection

If the terrestrial environment is permeated by dark matter, the levitation experiences damping forces and fluctuations attributed to dark matter. This paper investigates levitodynamics with multiple stochastic forces, including thermal drag, photon recoil, feedback, etc., assuming that all of these forces adhere to the fluctuation-dissipation theorem. The ratio of total damping to the stochastic damping coefficient distinguishes the levitodynamics from cases involving only one single stochastic force. The heating and cooling processes are formulated to determine the limits of temperature change. All sources of stochastic forces are comprehensively examined, revealing that dark matter collisions cannot be treated analogously to fluid dynamics. Additionally, a meticulous analysis is presented, elucidating the intricate relationship between the fundamental transfer cross-section and the macroscopic transfer cross-section. While the dark damping coefficient is suppressed by the mass of the levitated particle, scattering can be coherently enhanced based on the amount of the component microscopic particle, the nucleus form factor, and the static structure factor. Hence, dark damping holds the potential to provide valuable insights into the detection of the macroscopic strength of fundamental particles. We propose experimental procedures for levitation and employ linear estimation to extract the dark damping coefficient. Utilizing current levitation results, we demonstrate that the fundamental transfer cross section of dark matter can be of the order $\sigma^{\rm D}_{T}\lsim {\cal O}(10^{-26})\rm cm^2$

Speaker: Wenyu Wang (Beijing University of Technology)

levitodynamics.pptx

09:20 Hunting for wimps and beyond

Speaker: Lei Wu

2024 TOPAC-Hunting for WIMPs and Variants.pptx

09:45 Axion-like particle triggered baryogenesis

Speaker: Wei Chao

TOPAC-20240601-ChaoW.pdf

10:10 → 10:30 Break: coffee

10:30 → 12:10 Neutrino

Convener: Zhi-Wei Wang (UESTC)

10:30 Double-Weak Decays in the PandaX-4T Experiment

The possible Majorana nature of Neutrino is crucial for addressing profound questions such as the conservation of lepton number and the origins of the matter-antimatter asymmetry in the universe. Experimentally searching for Majorana neutrinos is one of the most important fields in the forefront of fundamental physics. The PandaX-4T detector, located in the China Jinping Underground Laboratory (CJPL), provides unique opportunities and high-quality data for this type of research through the double-week decays of Xe-136, Xe-134 and Xe-124. We will report the results and the progress of the double-week decay searches.

Speaker: Prof. 少博 王 (Shanghai Jiao Tong University)

TOPAC-PandaX4T-Shaobo.pptx

10:55 Towards a systematic study of non-thermal leptogenesis from inflaton decays

We investigates non-thermal leptogenesis from inflaton decays in the minimal extension of the canonical type-I seesaw model, where a complex singlet scalar $\phi$ is introduced to generate the Majorana masses of right-handed neutrinos (RHNs) and to play the role of inflaton. We systematically study non-thermal leptogenesis with the least model dependence. We give a general classification of the parameter space and find four characteristic limits by carefully examining the interplay between inflaton decay into RHNs and the decay of RHNs into the standard-model particles. We find that the strongly non-thermal RHNs scenario occupies a large parameter space, including the oscillation-preferred $K$ range, and works well for a relatively-low reheating temperature $T^{}_{\rm RH} \geq 10^3~{\rm GeV}$, extending the lower bound on the RHN mass to $2\times 10^{7}~{\rm GeV}$.
We demonstrate that such a unified picture for inflation, neutrino masses, and baryon number asymmetry can be realized by either a Coleman-Weinberg potential or a natural inflation potential for the inflaton. We find that non-thermal leptogenesis from inflaton decay offers a testable framework for the early Universe. The model-independent investigation of non-thermal leptogenesis should be useful in exploring this direction.

Speaker: Xinyi Zhang (Hebei University)

ntlep-XYZ.pdf

11:20 Neutrinoless double beta decay in seesaw models

Speaker: Yufeng Li

Beta-beta-Seesaw-20240601.pdf

11:45 The origin of pseudo-Nabmu-Goldstone-Boson Dark Matter

Speaker: Koji Tsumura

Koji_Tsumura.pdf

12:10 → 13:30 Lunch

13:30 → 15:10 DM

Convener: Yue-Lin Sming Tsai (Purple Mountain Observatory)

13:30 Quantum Theory of Dark Matter Scattering

Dark matter self-scattering is one of key ingredients for small-scale structure of the Universe, while dark matter annihilation is important for the indirect measurements. There is a strong correlation between the velocity-dependent self-scattering cross section and the Sommerfeld enhancement factor for the dark matter annihilation cross section. In this study, we formulate a direct relation between them by the use of Watson's (initial state/final state) theorem and Omnès solution, and our formulation reproduces the Sommerfeld enhancement factor, which directly computed by solving the Schrödinger equation, from the scattering phase shift.

Speaker: Takumi Kuwahara (Peking U)

TOPAC_Kuwahara.pdf

13:55 Freeze-in Dark Matter Explanation of the Galactic 511~keV Signal

We demonstrate, for the first time, the freeze-in dark matter, constituting 100% of the relic density can completely explain the Galactic 511 keV photon signal. In the talk, I will present two simple models for illustration. In both scenarios, the freeze-in mechanism generates the entire dark matter relic density, and thus any types of additional dark matter components produced from other sources are unnecessary.

Speaker: Wan-Zhe Feng (Tianjin University)

14:20 Probe Strongly Coupled Dark Sector via Gravitational Wave

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 non-perturbative 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 Polyakov-Nambu-Jona-Lasinio (PNJL) model, we discover that the relevant gravitational wave signatures are highly dependent on the various representations. We also find a remarkable interplay between the deconfinement-confinement and chiral phase transitions. In both scenarios, the future Big Bang Observer and DECIGO experiment have a higher chance to detect the gravitational wave signals. Most recently, via Quark-Meson model, we find the phase transition and thus gravitational wave signals will be significantly enhanced when the system is near conformal. In addition, we find that this effective field theory approach can be implemented to study the glueball dark matter production mechanism and for the first time provide a solid prediction of glueball dark matter abundance. Our prediction is an order of magnitude smaller than the existing glueball abundance results in the literature.

Speaker: Zhi-Wei Wang (UESTC)

Strongly Coupled Sectors and GW_v1_TOPAC2nd.pdf

14:45 Detecting a Fifth-Force Gauge Boson via Superconducting Josephson Junctions

Speaker: Yu Cheng

TOPAC_ChengYu_2024.pdf

13:30 → 15:10 GW

Convener: Huai-Ke Guo

13:30 Revisiting the fermion-field non-topological solitons and primordial black holes

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Speaker: Prof. Ke-Pan Xie (Beihang University)

Nanjing_TOPAC2024.pdf

13:55 A new first-order QCD phase transition in the early universe and gravitational waves

We discuss possible ways of extending the Standard Model quantum chromodynamics theory (QCD) theory and realize a first-order phase transition at high temperatures above 1 GeV without running into current constraints from both heavy ion colliders and early cosmology. The phase transition is from a non-perturbative effect of the QCD and can have a great impact on the early universe, including gravitational wave signals detectable for future space interferometers.

Speaker: Sichun Sun (Beijing Institute of Technology)

14:20 Graviton-photon conversion in atomic electric fields and high frequency gravitational wave detections

We study graviton-photon conversion in potential ground-based experiments. From graviton to photon transition, we calculate the cross section of graviton-atom interaction in the presence of spherical atomic electric fields; the obtained results hold for graviton energy around 100 keV to 1 GeV, and would be enhanced along the coherent length in extremely high frequencies; thus it gives a chance to catch MeV level gravitons from the universe with current neutrino facilities. From photon to graviton transition, we propose an experiment using entangled photon pairs to count missing photons passing through transverse magnetic tunnel, which could be used to verify the energy quantization of gravitational field.

Speaker: Gui-Rong Liang (China University of Mining and Technology)

15:10 → 15:30 Break: coffee

15:30 → 17:10 DM

Convener: Pei-Wen Wu

15:30 暗SU(2)下的矢量玻色子暗物质模型的一些较为一般的讨论

本报告将讨论SU(2)矢量暗物质模型中拉矢量的一般构造方式，最终保证暗物质稳定性离散群的一般破缺方式，以及标量粒子的简并模式。

Speaker: Yi-Lei Tang (中山大学)

暗 SU(2) 下的矢量玻色子暗物质模型的一些较为一般的讨论.pdf

15:55 Multi-messenger probes on dark matter surrounding black holes

The environment around the black hole can provide us with a promising playground to study the dark matter properties because of the large dark matter density from accretion.

I will explore the multi-messenger probes on the dark matter in the vicinity of black holes. More concretely, I will discuss (1) the multi-wavelength signals covering the radio, CMB and gamma rays which can arise from the dark matter annihilation/decay (2) the gravitational wave signals from a black hole binary whose dynamics is affected by the dark matter.

Speaker: kenji kadota

kadota1.pdf

16:20 A systematic investigation on dark matter-electron scattering in effective field theories

Speaker: Jin-Han Liang

20240601-Nanjing-DMDD-Jinhan_Liang.pdf

15:30 → 17:10 axion

Convener: Zuowei Liu

15:30 Discovering axions at muon experiments

Speaker: Lorenzo Calibbi

calibbi-TOPAC24.pdf

15:55 Probing lepton flavour violating ALPs at \mu^+\mu^+ and \mu^+ e^- colliders

Speaker: Lopamudra Mukherjee

TOPAC_Lopa_v2.pdf

16:20 Exploring interference effects between two ALP effective operators at the LHC

Speaker: Dr Chih-Ting Lu (Nanjing Normal University)

TOPAC2024_卢致廷.pdf

18:00 → 20:00 Banquet

Sunday, 2 June

08:30 → 10:10 Flavor

Convener: Tianjun Li (Institute of Theoretical Physics, Chinese Academy of Sciences)

08:30 Jet origin identification at CEPC

Speaker: Manqi RUAN (Institute of High Energy Physics, Beijing, China)

Jet Origin id & Impact - TOPAC.pdf

08:55 Outlook for Muon g-2 measurement

Speaker: Prof. Liang Li (Shanghai Jiao Tong University)

Muon_g-2_TOPAC2024.pdf

09:20 QCD axion dark matter and the cosmic dipole problem

TBD

Speaker: Chengcheng Han (Sun Yat-sen university)

axion.pdf

axion.pdf

09:45 New perspective of chiral symmetry

Speaker: Han-Qing Zheng

南京2024(1).pdf

10:10 → 10:30 Break: coffee

10:30 → 12:10 Astrophysics

Convener: Fupeng Zhang

10:30 Testing ultralight scalar field dark matter in high-redshift universe

Scalar field dark matter (SFDM) comprised of ultralight (m ∼ $10^{−22}$ eV) bosonic particles has received significant attention as a viable alternative to Cold Dark Matter (CDM), as it approximates CDM on large scales (≳ 1 Mpc) while potentially resolving some of its small-scale problems via kpc-scale quantum interference. However, the basic SFDM model described by a free real field, a.k.a. fuzzy dark matter (FDM), is recently challenged by a catch-22 problem: small boson masses yield the desired cores of dwarf galaxies but underpredict structure in the Lyman-α forest, whereas large boson masses render FDM effectively identical to CDM. Therefore, we propose to study the complex SFDM model with a possible self-interaction. A complex scalar field with U(1) symmetry results in the conservation of the associated Noether current, a new degree of freedom. We examine the dynamical implications of the Noether charge for large-scale structure and the Cosmic Microwave Background. We also discuss potential tests of SFDM by the 21cm line from the Cosmic Dawn and by the gravitational-wave (GW) signal from spinning black holes. Furthermore, we demonstrate that the kination phase resulted from complex SFDM can amplify the primordial GW background and thus explain the recent pulsar timing array results.

Speaker: Bohua Li (Guangxi University)

BohuaLi_TOPAC2024.pdf

10:55 Baryon overproduction constraints on the lepton flavor asymmetry in the early Universe

Anomalous transport phenomena, such as the chiral magnetic effect, are originated from the chiral anomaly of gauge theories and recently developed in hadron and condensed matter physics. They can also cause interesting phenomena in the early Universe when the chirality is a good conserved quantity at the temperature much higher than 100 TeV. An example is the chiral plasma instability, where helical hypermagnetic fields are amplified from chiral asymmetry, which will be the source of the baryon asymmetry through the hypermagnetic helicity decay. In particular, we point out that a large lepton flavor asymmetry before the electroweak symmetry breaking with satisfying total B-L to be zero, which has been thought not to be strongly constrained, generally corresponds to a large chiral asymmetry. This causes an amplification of a strong helical magnetic field, which leads to baryon overproduction. We find that this gives a stronger constraint on the lepton flavor asymmetry than the one given weakly from the BBN. In a similar way that a large lepton asymmetry before the electroweak symmetry breaking is constrained by the SU(2) electroweak sphalerons/chiral anomaly to avoid the baryon overproduction, we conclude that a large lepton flavor asymmetry is constrained by the U(1) hypergauge chiral anomaly.

Speaker: Kohei Kamada (HIAS UCAS)

KK_0602TOPAC.pdf

11:20 Primordial black holes from slow phase transitions: a model-building perspective

We discuss the relation between the Higgs potential structure and primordial black hole (PBH) formations. Recently, it has been discussed that PBHs can be formed by first-order phase transitions at the early Universe. In this talk, we consider the PBH formation mechanism through delayed first-order phase transitions at the early Universe. If the phase transition is delayed, the large energy density fluctuation can be realized between symmetry broken and unbroken regions. If the density fluctuation can be larger than a certain criterion, the overdensity region may collapse to PBHs. We discuss the form of the Higgs potential needed to realize this PBH formation. In addition, we show that the commonly used exponential approximation of the bubble nucleation rate fails to capture such PBH formation.

Speaker: Masanori Tanaka (Peking University)

TOPAC2024_Tanaka.pdf

11:45 Cosmological phase transitions in the Holographic models for the composite Higgs boson

The composite Higgs boson scenario assumes the existence of a new strongly coupled gauge sector with a softly broken approximate hyperflavor symmetry. At low energies the corresponding dynamics may be studied with help of the holographic techniques inspired by AdS/QCD. We present the bottom-up soft-wall holographic model that admits a first-order phase transition and, using a perturbation theory near the critical point, describe the production of the gravitational wave background by bubble nucleation processes in the thin-wall approximation. We also employ the approximation of the large number of spacetime dimensions to describe inhomogeneous black hole solutions dual to the gauge sector behavior in the bubble wall.

Speaker: Oleg Novikov (Saint-Petersburg University)

10:30 → 12:10 Flavor

Convener: Lorenzo Calibbi

10:30 Recent progress of Dark SHINE R&D

Dark SHINE is a newly proposed fixed-target experiment at SHINE (Shanghai high repetition rate XFEL and extreme light facility, being the 1st hard X-ray FEL in China) under construction targeting completion in 2026. Dark SHINE aims to search for the new mediator, Dark Photon, bridging the Dark sector and the ordinary matter. In this work and presentation, we present the idea of this new project and 1st prospective study in search for Dark Photon decaying into light dark matter. It also provides the opportunity to incorporate broader scope of BSM search ideas such as ALP, utilizing the fixed-target experiment of this type.

Speaker: Kun Liu (TDLI / SJTU)

DarkSHINETOPAC2024.pdf

DarkSHINETOPAC2024.pptx

10:55 Recent $B^+ \to K^+ \nu \bar\nu$ excess at Belle II, (dark) SMEFT, and flavour structure

Recently, the Belle II collaboration announced the first measurement of $\mathcal B(B^+\to K^+\nu\bar\nu)$, which is found to be about $2.7\sigma$ higher than the SM prediction. We decipher the data with two new physics scenarios: the underlying $b\to s \nu\bar\nu$ transition is, besides the SM contribution, further affected by heavy new mediators that are much heavier than the EW scale, or amended by an additional decay channel with undetected light final states like dark matter or axion-like particles. These two scenarios can be most conveniently analyzed in the SMEFT and the dark SMEFT (DSMEFT) framework, respectively. We consider the flavour structures of the resulting effective operators to be either generic or satisfy the minimal flavour violation (MFV) hypothesis, both for the quark and lepton sectors.

Speaker: 袁 兴博

11:20 On the SM quark/lepton masses in an SU(8) theory

We describe the SM quark/lepton masses in an SU(8) theory, where three-generational SM fermions are non-trivially embedded. A set of d=5 operators that break the emergent global symmetries in the chiral fermion sector due to the Planck scale effects are sufficient to generate the light SM quark/lepton masses as well as the CKM mixing pattern, with one single SM Higgs doublet in the spectrum.

Speaker: ning chen (Nankai University)

SU8_talk.pdf

11:45 $B$ meson anomalies and large $B^{+}\to K^{+}\nu\bar{\nu}$ in non-universal $U(1)^\prime$ models

In view of both the latest LHCb measurement of $R_{K^{(*)}}$ and the new $2.7\sigma$ deviation reported by Belle II on $B^{+}\to K^{+}\nu\bar{\nu}$ decays, we present a fit to the $B$ meson anomalies for various one and two dimensional hypothesis including complex Wilson coefficients. We show in a model-independent way that the generic non-universal $U(1)^{\prime}$ extensions of the SM, without flavour violation, fail to simultaneously fit those observables and corroborate that they can modify $\mathrm{BR}(B^{+}\to K^{+}\nu\bar{\nu})$ up to only a $10\%$. In view of this deficit, we propose a new way in which those models can accommodate the data at tree level by introducing lepton flavour violating couplings and non-diagonal elements of the charged lepton mixing matrix, with implications in future charged lepton flavour violation searches.

Speaker: CRISTIAN FELIPE SIERRA FONSECA (Nanjing Normal University)

NNU_TOPAC_talk.pdf

12:10 → 13:30 Lunch

13:30 → 14:45 Astrophysics

Convener: Lijing Shao (Peking University)

13:30 Extreme mass ratio inspirals in evolving nuclear star clusters

Recently we have build a Monte-Carlo method that can obtain self-consistent solutions of an evolving nuclear star cluster that contains a central massive black hole. Our method evolves the orbits of stellar objects by solving two-dimensional (energy and angular momentum) Fokker-Planck equations given multiple mass components. In this study we apply our method to investigate the evolution of the rates of extreme mass ratio inspirals over cosmic time.

Speaker: Fupeng Zhang

Emris in Evolving nuclear star cluster.pdf

13:55 12m kHz GW detector prototype at Beijing Normal University

Speaker: Mengyao Wang

TOPAC2024_Wang_Mengyao_v3.pdf

14:20 Probing ultralight particles with gravitational waves

Speaker: Huan Yang

Talk_Yang_Huan.pdf

14:45 → 15:15 Break: coffee

15:15 → 16:30 Astrophysics

Convener: Xiao-Gang He

15:15 CPTA current status and future expectation

Speaker: Heng Xu

20240602-TOPAC_HengXu.pdf

15:40 Searching for Ultralight New Particles with Spin-Polarized Systems

Speaker: Wei Ji

Talk_Nanjing_2405_TOPAC_Ji_Wei.pdf

16:05 Recent Status and Results of the Dark Matter Particle Explorer

DAMPE是一颗空间宇宙线探测器，于2015年12月成功发射，并在轨运行多年，已经取得多项科学成果。DAMPE主要的科学目标有暗物质间接探测、宇宙线物理和高能伽马射线天文学。本报告重点介绍DAMPE的探测器研制，合作组组成和在轨运行情况。并介绍DAMPE已取得的科学成果，以及数据的物理解读。

Speaker: Lei Feng (中国科学院紫金山天文台)

Recent Status and Results of the Dark Matter Particle Explorer.pptx

16:30 → 16:45 Closing