### Conveners

#### Evening Session

- Kiyoharu Kawana (KIAS)
- TaeHun Kim (KIAS)

#### Evening Session

- Jaehoon Jeong (KIAS)
- Dibyendu Nanda (Indian Association for the Cultivation of Science)

#### Evening Session

- Xing-Yu Yang
- Raymundo Ramos (KIAS)

We study the phenomenological signatures associated with a light fermiophobic Higgs boson within the type-I two-Higgs-doublet model at the HL-LHC. Our exhaustive parameter scan revealed a captivating mass range between 1 GeV and 10 GeV. This range retains a substantial number of viable parameter points, primarily due to the current experimental difficulties in probing soft decay products of...

A singlet majoron can arise from the seesaw framework as a pseudo-Goldstone boson when the heavy Majorana neutrinos acquire masses via the spontaneous breaking of global U(1)_L symmetry. The resulting cosmological impacts are usually derived from the effective majoron-neutrino interaction, and the majoron abundance is accumulated through the freeze-in neutrino coalescence. However, a...

We discuss a possibility to solve fine-tuning problems based on micro-canonical formulation of quantum field theory.

Scattering Amplitudes are crucial to understanding the range of validity of effective field theories. In this talk I will talk about the unitarity and validity of extra dimensional gravity and demonstrate that the Goldstone Boson Equivalence Theorem ensures that high energy scattering of massive Kaluza-Klein states are unitary through a series of Ward Identities. Furthermore I will show that...

511 keV gamma-ray excess from the Galactic center is a long lasting anomaly without satisfying astrophysical explanation. Hawking evaporation of hypothetical primordial black hole (PBH) with mass ${\color{blue}1.0\times 10^{-17} \lesssim M_{\rm PBH}/M_\odot \lesssim 8.0\times 10^{-17}}$ and fractional abundance ${\color{blue}10^{-3} \lesssim f_{\rm PBH} \lesssim 1.0}$, gives rise substantial...

In my talk I will discuss our recent work in studying the prospects to look for Dark Matter in Gravitational Wave Detectors, in particular in KAGRA. While the prospects for conventional particle Dark Matter are rather bleak, it might be possible to detect heavy (kg-scale) Dark Matter. If time allows, I will also briefly comment on other peoples work looking for very light Dark Matter in KAGRA.

This study investigates the classical Higgs inflation model with a modified Higgs potential fea- turing a dip. We examine the implications of this modification on the generation of curvature perturbations, stochastic gravitational wave production, and the potential formation of primordial black holes (PBHs). Unlike the classical model, the modified potential allows for enhanced power spectra...

We assessed the sensitivity of SKA-like pulsar timing measurements to probe signals of a first order phase transition (FOPT) scenario in the dark sector, which gives rise to primordial black holes (PBHs) and stochastic gravitational waves (GWs). We considered the mechanism where the PBHs are formed from the collapse of Fermi balls created from dark matter filtered out of true vacuum bubbles....