The 5th workshop on Symmetry and Structure of the Universe (SSU 2026 Busan)

Contribution List

6. Cornering axions 
with astrophysical transients

Edoardo Vitagliano (Max Planck Institute for Physics)

While it is way too early to make a final judgement, it is noteworthy that searches at LHC and direct detection experiments reported null results, therefore boosting the ever growing interest in sub-GeV dark sector candidates. Owing to their high temperature and density, the cores of proto-neutron stars, remnant of core-collapse supernovae and neutron star mergers, can be factories of axions...

5. CSM for BSM

Chui-Fan Kong (IBS-CTPU-PTC)

Core-collapse supernovae are powerful probes of physics beyond the Standard Model (BSM). In this talk, I will show how the circumstellar medium (CSM) affects supernova-based BSM searches using dark photons as an example. The decay product of dark photon can heat up CSM and lead to extra blackbody emission. Using the early-time observations of SN 2023ixf, we derive the strongest constraint on...

3. Inclusive vs exclusive $b\to s \mu\mu$: probing nonperturbative effects

Enrico Lunghi (Indiana University)

Over the past decade, the LHCb and CMS experiments have reported persistent tensions in several branching fractions and angular observables of exclusive $b \to s \mu^+\mu^-$ decays. Taken together, these discrepancies exceed the five-standard-deviation level. However, their interpretation remains the subject of active debate, particularly regarding the size and treatment of nonperturbative QCD...

4. Isocurvature Induced Gravitational Waves at Pulsar Timing Arrays

Peizhi Du (University of Science and Technology of China)

The standard cosmological model (ΛCDM model) assumes adiabatic initial conditions for primordial density perturbations. However, many new physics scenarios can deviate from this assumption and generate isocurvature perturbations across a wide range of scales. In this talk, I will discuss how isocurvature can induce gravitational waves at second order in perturbation theory. Moreover, Pulsar...

8. On the Consistency of Dynamical Gauge Couplings

Michael Shamma (Korea Institute for Advanced Study)

We study the low-energy behavior of gauge couplings in the presence of dynamical scalar backgrounds. In weakly coupled, renormalizable four-dimensional theories, gauge invariance restricts the dependence on the scalar background to be logarithmic. The gauge coupling evolution in these scenarios can be entirely described by the renormalization-group running with dynamical mass thresholds....

2. Photon axion enhancement around PBH

Junghoon Joh (SungKyunKwan University)

Dark matter (DM) can be gravitationally captured around a massive compact object, forming a dense halo. If primordial black holes (PBHs) exist, surrounding dark matter particles can be accreted through gravitational attraction, leading to the formation of a DM halo with a steep spike profile near the PBH.

If the dark matter consists of axions or axion-like particles (ALPs), the high number...

7. Reconstructing the Dark Matter Equation of State with Compact Object Inspirals

Boris Betancourt Kamenetskaia (Institute for Basic Science CTPU-CGA)

Can gravitational waves reveal the properties of dark matter? Compact binaries embedded in extended dark matter configurations provide a unique opportunity to probe the macroscopic behavior of the dark sector. If a neutron star or black hole is surrounded by a sufficiently massive and extended dark matter envelope, an inspiraling companion experiences dynamical friction in addition to the...