We study the signature of the final stage of the evaporation of primordial black holes (PBH), focusing on high energy neutrinos and gamma-rays. For distributions of PBH with finite widths in mass spectrum, we derive a new upper limits $f_{\rm PBH} \lesssim 10^{-4} - 1$ for $M_{\rm PBH} = 10^{15-20}$ g by utilizing the IceCube latest data set of diffuse neutrinos for $E_\nu \geq 30$ TeV. We...
n the WIMP framework, the Higgs portal has a relatively small Higgs–nucleon interaction compared to other mechanisms, and, since the mediator is the Higgs boson, it is subject to fewer theoretical constraints. However, recent improvements in the precision of direct detection experiments have placed increasing pressure on Higgs-portal dark matter models. In simple models, the preferred DM mass...
Cosmic inflation was introduced to address several shortcomings of the standard Big Bang cosmology. The observed red tilt of the CMB power spectrum and potential future detection of primordial gravitational waves could provide valuable clues to reconstructing the inflaton potential. Recent small scale CMB measurements from the Atacama Cosmology Telescope (ACT), combined with Planck data,...
Cosmic strings are one-dimensional topological defects that arise from the spontaneous symmetry breaking in the early universe. In particular, superconducting cosmic strings, which have attracted attention from an astrophysical perspective, are characterized by their interactions with matter fields and are thought to have formed during the grand unification epoch. Cosmic strings have been...
BlackHawk is a widely used tool for computing the secondary spectra of particles emitted via Hawking radiation from evaporating black holes. In order to account for particle hadronization and decay processes, it employs different computational backends—such as Hazma, PYTHIA, and HDMSpectra—depending on the energy scale of the initial emission. While effective in separate regimes, this hybrid...
We present a unified study of vector dark matter (VDM) from hidden gauge symmetries U(1)D or SU(2)D. Starting from the renormalizable Higgs-portal UV theory for VDM with a dark Higgs field, we integrate out the radial mode of the dark Higgs to derive the leading low-energy interactions for Higgs-portal VDM, which are constrained into the validity domain in the UV theory. We also make the VDM...
In the standard model, the mechanism for gauge symmetry breaking and the theoretical origin of the Higgs boson remains unclear.
Non-Abelian gauge theories in higher dimensions are good candidates to address this issue.
We have constructed a Non-Abelian gauge theory with extra dimensions of two-dimensional sphere. In this model, compared to conventional models such as those with $S^1$ and...
COSINE-100 is an experiment designed to search for dark matter interactions using an array of scintillating NaI(Tl) crystals, which serve as both the WIMP interaction target and detector. We have found that contamination on the crystal surface affects the energy range of the dark matter signal. To improve the performance of detectors, we have developed cleaning methods using organic solvents...
We propose a novel and comprehensive particle physics framework that addresses multiple cosmological tensions observed in recent measurements of the Hubble parameter, S8, and Lyman-α forest data. Our model, termed `{\bf SIDR+zt}' (Self Interacting Dark Radiation with transition redshift), is based on an inelastic dark matter (IDM) scenario coupled with dark radiation, governed by a U(1)D gauge...
Dark matter (DM) environments around black holes (BHs) can influence their mergers through dynamical friction, causing gravitational wave (GW) dephasing during the inspiral phase. While this effect is well studied for collisionless dark matter (CDM), it remains unexplored for self-interacting dark matter (SIDM) due to the typically low DM density in SIDM halo cores. In this work, we show that...
We investigate dark gauge-mediated supersymmetry breaking with an unbroken U(1) gauge symmetry and a massless dark photon. Messengers charged under both Standard Model and dark gauge groups generate new soft SUSY-breaking terms via gauge kinetic mixing. Large mixing significantly alters superpartner spectra compared to standard GMSB, reduces the μ parameter, and predicts a relatively light...
Primordial black holes (PBHs) formed during the early universe provide a unique probe of physics beyond the Standard Model. In this study, we investigate the impact of additional degrees of freedom from supersymmetry (SUSY) particles and the memory burden effect (MBE) on the evaporation process of PBHs formed via first-order phase transitions. By analyzing how these factors influence the PBH...
If the B – L symmetry is gauged with the addition of right-handed neutrinos, the standard model B – L current is anomalous with respect to the B – L gauge field itself. Then, the anomaly relation implies that the magnetic helicity of the B – L gauge field is related to the standard model B – L charges, although the whole universe is B – L neutral with right-handed neutrinos. Based on this, we...
We propose a hybrid inflationary scenario based on eight-flavor hidden QCD with the hidden colored fermions being in part gauged under U(1) B-L symmetry. This hidden QCD is almost scale-invariant, so-called walking, and predicts the light scalar meson (the walking dilaton) associated with the spontaneous scale breaking, which develops the Coleman-Weinberg (CW) type potential as the consequence...
We consider the boosted dark matter(BDM) model that consists of two-component dark matter with the boost effect from the annihilation of heavier DM into lighter one and the self-heating effect from the self-interaction of lighter DM. These effects suppress the formation of small-scale structures, and this suppression affects 21cm signal. We expect that BDM model will change 21cm signal and...
We present a minimal setup within the framework of Horndeski gravity that describes a nonpathological Genesis scenario. Our setup allows for a fully stable transition to the kination epoch, during which General Relativity (GR) is restored. This Genesis scenario circumvents the no-go theorem, albeit at the cost of encountering the risk of strong coupling in the past. Interestingly, our scenario...
We investigate the electroweak phase transition (EWPT) and collider phenomenology in the Two-Higgs-Doublet Models (2HDM). The interplay between the thermal properties of the scalar potential and experimental constraints offers a promising framework to explore beyond the Standard Model physics. We analyze scenarios that may realize a strong first-order phase transition (SFOPT), which is...
We propose a new collider signature for neutral long-lived particles (LLPs): an emerging photon jet in the hadronic calorimeter (HCAL), from LLP decays to photons with no ECAL activity or tracks. Using the ultralight fermiophobic Higgs $h_f$ in the Type-I 2HDM as a benchmark, we study
$pp \to H^\pm h_f \to W^\pm h_f h_f$
where one $h_f$ decays in the ECAL and the other in the HCAL. Fast...
