2026 CAU Beyond the Standard Model Focus Workshop

Feb 9, 2026, 9:00 AM → Feb 12, 2026, 6:00 PM Asia/Seoul

Chung-Ang University

The 2026 Chung-Ang University Beyond the Standard Model Focus Workshop (CAU BSM Focus) is the sixth international meeting on Physics Beyond the Standard Model (Higgs, Dark Matter, Neutrino, Axion, Inflation, Gravitational Waves) in Chung-Ang University, Korea. The aim of the BSM Workshop is to discuss interesting current topics and initiate the collaboration between experts and participants working on BSM physics in the globe. The sixth workshop will be to focus on the theoretical aspects of recent development on the connection between Cosmology and Particle Physics. 

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Invited speakers

 

Wenyuan Ai (TDL Institute)

Katsuki Aoki (Kyoto Univ)

Shuntaro Aoki (RIKEN)

Carlo Branchina (Univ of Calabria)

Eung Jin Chun (KIAS)

Minxi He (IBS-CTPU-PTC)

Alejandro Ibarra (TUM)

Sang Hui Im (IBS-CTPU-PTC)

Yongsu Jho (Yonsei Univ)

Dong Woo Kang (Jeonbuk National Univ)

Joern Kersten (Bergen/Yonsei Univ)

Seong-Sik Kim (Chungnam National Univ)

Chui-Fan Kong (IBS-CTPU-PTC)

Jong-Wan Lee (IBS-CTPU-PTC)

Sung Hak Lim (IBS-CTPU-PTC)

Adriana Menkara (DESY)

Kyohei Mukaida (KEK)

Alberto Navarro (Seoultech)

Shohei Okawa (APCTP)

Takashi Toma (Kanazawa Univ)

Bin Xu (KIAS)

Kimiko Yamashita (Ibaraki Univ)

Jong-Hyun Yoon (Chungnam National Univ)

 

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Information

The fifth series: 2025 CAU BSM Workshop

The fourth series: 2024 CAU BSM Workshop

The third series: 2023 CAU BSM Workshop

The second series: 2022 CAU BSM Workshop

The first series: 2021 CAU BSM Workshop

CAU THEP Group: https://sites.google.com/site/cautheplab

Mon, February 9

9:30 AM → 10:30 AM S1

Convener: Prof. Hyun Min Lee (CAU - Chung-Ang University (KR))

9:30 AM Neutrino signals from dark matter spikes

We summarize the status of dark matter indirect searches using neutrinos as messengers, and we point out that dark matter spikes around supermassive black holes can enhance significantly the neutrino flux from nearby galaxies, possibly even at the reach of neutrino telescopes. In particular, we propose that the measured neutrino flux from NGC1068 could be attributed to dark matter annihilations, for parameters escaping detection from the Milky Way center, due to the strong stellar heating of the spike in the latter.

Speaker: Alejandro Ibarra (Technical University of Munich)

10:00 AM Boosted Dark Matter: Theory and Detection Prospects

Speaker: Dr Takashi Toma (Kanazawa University)

10:30 AM → 11:00 AM Coffee break

11:00 AM → 12:30 PM S2

Convener: Dr Jongkuk Kim (Chung-Ang University)

11:00 AM Parity Violation in Spin-1 Dark Matter with EFT Descriptions

Speaker: Prof. Kimiko Yamashita (Ibaraki University)

11:30 AM Taming the dark photon production via a non-minimal coupling to gravity

I begin with a pedagogical introduction to cosmological particle production during and after inflation, reviewing the theoretical framework of inflaton dynamics, gravitational particle production, and numerical techniques. I discuss various production scenarios studied in different cosmological contexts, with emphasis on computational methods and challenges. I then present our recent work on massive vector dark matter with non-minimal couplings to gravity. Recent studies revealed "runaway" instability in such theories within the effective field theory (EFT) framework. We show this is an artifact of pushing the EFT beyond its validity regime. We construct explicit UV-complete models where non-minimal couplings arise from heavy scalars or Kaluza-Klein gravitons. These completions yield form-factors that automatically satisfy stringent constraints and eliminate all instabilities. We numerically reproduce the dark photon production and delineate the validity boundary, showing that the runaway instability appears only outside the EFT's regime of validity.

Speaker: Jong-Hyun Yoon

12:00 PM Fermion reheating with a quartic inflaton potential

Speaker: Adriana Menkara

12:30 PM → 2:30 PM Lunch

2:30 PM → 3:30 PM S3

Convener: Dong Woo Kang (KIAS)

2:30 PM Deep learning approaches to top FCNC couplings to photons at the LHC

Speaker: Dr Adil Jueid (Institute for Basic Science)

3:00 PM Chasing the two-Higgs-doublet model via electroweak corrections at e+ e− colliders

We present a comprehensive study of Higgs boson production associated with a neutrino pair at e+e− colliders (e+e−→hνν¯) at the next-to-leading-order accuracy in both the Standard Model and the two-Higgs-doublet model. We show that new physics effects from the extended Higgs sector can be probed through electroweak corrections, which lead to several percent deviations from the Standard Model predictions in total cross sections and differential distributions, even in the alignment limit. This highlights the potential of precision studies at future e+e− colliders for searching new physics.

Speaker: Tatsuya Banno

3:15 PM Electric Dipole Moment of Electron induced by Electroweak Multiplet at Full Three-loop

There has been remarkable progress in recent years in the electric dipole moment (EDM) measurements of electron using paramagnetic atom or molecule. In a previous study, we calculated the contribution to the electron EDM induced by the CP-violating Yukawa interaction of electroweak multiplets at the three-loop level in effective field theory. We found that this contribution might reach the sensitivity of future EDM experiments. However, this calculation involves an uncertainty relating to threshold corrections that cannot be evaluated in the effective field theory. In this study, we calculate the electron EDM induced by electroweak multiplets at full three-loop. As a result, we found that the threshold correction contributes at the same order as the result of the effective field theory and that the full result is larger than the previous study. This talk is based on JHEP02(2025)082 and a content being written in a paper.

Speaker: Kiyoto Ogawa (Nagoya.Univ)

3:30 PM → 4:00 PM Coffee break

4:00 PM → 5:00 PM S4

Convener: Dr Sang Hui Im (IBS CTPU)

4:00 PM Entanglement in Higgs Scattering and possible connection to symmetry

Speaker: Ms ROJALIN PADHAN (Institute of Physics, Bhubaneswar)

4:30 PM SUSY and non-SUSY analysis of truly confining gauge theories

We classify 4D N=1 truly confining supersymmetric gauge theories, in which no center charges can be screened. This property guarantees that Wilson loops in the fundamental representation exhibit an area law. We systematically identify all such theories for simple Lie groups and determine the allowed matter content. In each theory, we find condensing magnetic operators, which are expected to explain confinement via the dual Meissner effect. We also analyze the non-SUSY versions of truly confining gauge theories and identify stable vacua that indicate confinement via the dual Meissner effect.

Speaker: Shota Saito (Kavli IPMU)

SUSY and non-SUSY analysis of truly confining gauge theories.pdf

4:45 PM Dynamical friction for circular orbits in self-interacting ultralight dark matter and Fornax globular clusters

We investigate the impact of repulsive self-interaction in ultralight dark matter (ULDM) on dynamical friction in circular orbits in ULDM halos and its implications for the Fornax dwarf spheroidal (dSph) galaxy's globular clusters. Using the Gross-Pitaevskii-Poisson equations, we derive the dynamical friction force considering soliton density profiles for both non-interacting and strongly self-interacting ULDM. Our results show that self-interactions reduce the dynamical friction effect further than both the non-interacting ULDM and standard cold dark matter models. Furthermore, we derive the low Mach number approximation to simplify the analysis in the subsonic motion, where the tangential component of dynamical friction dominates. Applying these findings to the Fornax dSph, we calculate the infall timescales of globular clusters, demonstrating that strong self-interaction can address the timing problem more effectively. We constrain the parameter space for ULDM particle mass and self-coupling constant, which are consistent with other constraints from astronomical and cosmological observations.
This paper is published in JCAP 01 (2026) 020 [arXiv:2504.19219]

Speaker: Hyeonmo Koo

Tue, February 10

9:30 AM → 10:30 AM S5

Convener: Joern Kersten (University of Bergen)

9:30 AM Spontaneous Leptogenesis in Type I Seesaw

Speaker: Eung Jin Chun (Korea Institute for Advanced Study)

10:00 AM Quantum enhanced sensing for ultralight dark matters

Speaker: Bin Xu

10:30 AM → 11:00 AM Coffee break

11:00 AM → 12:30 PM S6

Convener: Dr Adil Jueid (Institute for Basic Science)

11:00 AM Identifying high energy sources of CP violation and PQ breaking with electric dipole moments

Speaker: Dr Sang Hui Im (IBS CTPU)

11:30 AM Rare meson decays with dark matter emission

Speaker: Shohei Okawa (APCTP)

12:00 PM Dark pion scattering and vector resonance in Sp(4) gauge theory

Speaker: Jong-Wan Lee (Institute for Basic Science (IBS))

12:30 PM → 3:00 PM Lunch and discussion

3:00 PM → 4:00 PM S7

Convener: Seongsik Kim (Chung-Ang University)

3:00 PM Testing neutrino mass origins with supernova neutrinos

Speaker: Chui-Fan Kong

3:30 PM Self-resonant dark matter with Z_4 gauged symmetry

Speaker: Lucca Radicce Justino

3:45 PM Stable dark matter from Pauli blocking in the degenerate fermion background with Quantum Field Theory

We study a mechanism to make dark matter stable based on the Pauli blocking in the fermion background. In the background where fermions occupy the states, the decay of dark matter to those final states is not allowed, as a result, DM becomes stable. We derive the evolution equations of the distribution function in the quantum field theory and compare it with the Boltzmann equation. We apply this mechanism to a realistic model of neutrino and dark matter.

Speaker: Junghoon Joh (SungKyunKwan University)

4:00 PM → 4:30 PM Coffee break

4:30 PM → 5:45 PM S8

Convener: Shohei Okawa (APCTP)

4:30 PM Aspects of Sommerfeld Enhancement in the light of Halo gamma-ray excess

Speaker: Yongsoo Jho

5:00 PM Neutrino masses and mixed dark matter from doublet and singlet scalars

We consider the extension of the SM with an inert scalar doublet,
three right-handed neutrinos, and singlet scalar fields, ϕ and S. In this model, neutrino
masses are zero in the limit of the unbroken Z4 discrete symmetry. We show that when the
singlet scalar field ϕ gets a VEV, the Z4 symmetry is broken to Z2, and neutrino masses
are generated at one-loops due to the mixings between the neutral components of the inert
scalar doublet and the singlet scalar field S. There is a dark matter candidate from the
lightest neutral scalar field, which is a mixture of the inert scalar doublet and the singlet
scalar field S, in general. The Z4 breaking mass terms are constrained by electroweak
precision data and direct detection (DD) bounds for dark matter, favoring small mixings
or almost degenerate masses for the DM scalars. As a result, we discuss the implications
of the results for small neutrino masses and DD-safe dark matter. Finally, we discuss on the possible collider signatures in our model.

Speaker: Seongsik Kim (Chung-Ang University)

Wed, February 11

9:30 AM → 10:30 AM S9

Convener: Prof. Kimiko Yamashita (Ibaraki University)

9:30 AM From Scattering Amplitudes to Black Holes

Speaker: Katsuki Aoki (YITP, Kyoto University)

10:00 AM Black holes as a probe of BSM particles

Astrophysical probes are powerful tools to search for Beyond the Standard Model (BSM) particles, complementary to terrestrial detectors. As commonly exist throughout the Universe, black holes (BH) are intriguing astrophysical objects due to their strong gravity that can help to study BSM particles. In this talk, I will show that BSM particles can interact and form structures around BHs, here called environment. Depending on the masses of BSM particles, the density profiles of dense environments show different features which can be probed by various observations, such as gravitational waves. Particularly in a binary system of a BH and a companion, if such BSM environments exist, the evolution of the binary will deviate from the predictions of general relativity, which can lead to observable signals and be detected.

Speaker: Dr Minxi He

10:30 AM → 11:00 AM Coffee break

11:00 AM → 12:30 PM S10

Convener: Adriana Menkara

11:00 AM Modular Cosmology: Implications for Inflation

Modular symmetry arises in various extensions of the Standard Model and plays an important role in particle phenomenology, particularly as a framework for flavor symmetries. In this talk, I will explore the cosmological implications of modular symmetry, with a special focus on inflationary physics. I will discuss how specific couplings between moduli and the Standard Model sector can influence inflationary dynamics and leave characteristic imprints on inflationary observables.

Speaker: Shuntaro AOKI

11:30 AM Constraining Inflation via FIMP dark matter using the β-function with collider implications

Speaker: Sarif Khan (Goettingen University)

12:00 PM Peccei Quinn genesis

Speaker: Junho Song

12:15 PM Higgs pole inflation in the light of ACT data

Speaker: Jeonghak Han

12:30 PM → 2:30 PM Lunch

2:30 PM → 3:45 PM S11

Convener: Shuntaro AOKI

2:30 PM Belle II excess and dark matter

The Belle II Collaboration recently announced the first observation of the 𝐵 → 𝐾 + 𝜈 𝜈 decay process. This decay channel provides a particularly clean signal and allows for high theoretical precision. However, their measurement shows a 2.7𝜎 deviation from the Standard Model prediction. To address this excess, we study a scalar dark matter model. Assuming a dark 𝑈 (1)𝑋≡𝑈(1)𝐿𝜇−𝐿𝜏 symmetry, this symmetry is spontaneously broken to a local discrete symmetry, which guarantees the stability of dark matter. Within this framework, we can simultaneously explain the recent excess in B r (𝐵→𝐾+ 𝜈𝜈) reported by the Belle II Collaboration and the observed relic abundance of dark matter.

Speaker: Dr Jongkuk Kim (Chung-Ang University)

3:00 PM The Seesaw Route to Neutrino Asymmetry and Baryogenesis in light of EMPRESS observation

We present a type-I seesaw scenario within the supersymmetric $U(1)_{B-L}$
extension of the Standard Model that simultaneously explains the large electron–neutrino asymmetry suggested by EMPRESS and the observed tiny baryon asymmetry. Both asymmetries originate from the decay of the $B−L$ Higgs condensate dominating the early Universe. It`s early rare decays into heavy right-handed neutrinos generate baryon asymmetry via resonant leptogenesis, while later decays produce a large lepton asymmetry. The correct magnitudes are obtained for normal neutrino mass hierarchy. The model also predicts a gravitational-wave background from cosmic strings, potentially observable by ultimate DECIGO.

Speaker: Arghyajit Datta

3:30 PM Periodic dynamics induced by wave dark matter: From neutrino to superconductor

The oscillating wave dark matter can act as a periodic driver, producing distinct modulation signatures not only in particle physics (e.g., neutrinos), but also in solid-state physics (e.g., superconductors). This talk is based on our recent papers PRD 108, 095028 (2023); JHEP 07 (2025) 269; arXiv: 2509.22892.

Speaker: Yechan Kim (KAIST)

3:45 PM → 4:15 PM Coffee break

4:15 PM → 5:15 PM S12

Convener: Ms ROJALIN PADHAN (Institute of Physics, Bhubaneswar)

4:15 PM Spin Correlation and Quantum Observables at Colliders

Speaker: Dong Woo Kang (KIAS)

4:45 PM Quantum Correlations at the LHC

Speaker: Alberto Navarro (Seoultech)

6:30 PM → 8:30 PM Banquet

Thu, February 12

9:30 AM → 10:30 AM S13

Convener: Carlo Branchina (Università della Calabria)

9:30 AM Gravitational Wave Messages from Dark Sectors and Grand Unification

Speaker: Joern Kersten (University of Bergen)

10:00 AM A new mechanism of gravitational wave production

First-order phase transitions in the early Universe are a well-motivated source of gravitational
waves (GWs). In this talk, I will discuss a previously overlooked GW production mechanism:
gravitational transition radiation, arising from graviton emission by particles whose mass changes
as they pass through expanding bubble walls. The resulting spectrum features a distinctive shape with a peak frequency redshifting to f_peak ∼ T0 ∼ 10 GHz, where T0 is the current temperature of the Universe. This mechanism is generic and is expected to operate similarly for domain walls and other relativistic interfaces.

Speaker: Wenyuan Ai

10:30 AM → 11:00 AM Coffee break

11:00 AM → 12:30 PM S14

Convener: Arghyajit Datta

11:00 AM Electroweak phase transition and bubble wall dynamics

Speaker: Carlo Branchina (Università della Calabria)

11:30 AM Magnetic Helicity, Higgs Winding, and Chiral Asymmetry

Speaker: Kyohei Mukaida (DESY)

12:00 PM Understanding Galactic Dark Matter with Generative Models and Physics-Informed Neural Networks

Mapping the Milky Way’s dark matter requires moving beyond traditional, rigid dynamical models. In this talk, generative models—specifically Normalizing Flows— are used to learn the stellar phase space distribution directly from Gaia data. This approach enables a flexible, model-independent reconstruction of the Galactic gravitational potential and local dark matter density. These data-driven techniques provide a promising avenue to handle complex observational biases and what they reveal about the dark sector's influence on our Galaxy.

Speaker: Sung Hak Lim (Rutgers University)

12:30 PM → 2:00 PM Lunch and discussion