Axion is one of the well-motivated candidates for dark matter and there have been many attempts for axion dark matter search. In this talk, we show novel aspects of the axion dark matter, which significantly modify the physics of vortex in the Abelian-Higgs model. Due to the axion-photon conversion, electromagnetic fields are induced in the magnetic core of the vortex. In numerical...
Axion inflation can have a Chern-Simons coupling to gauge fields. Depending on the gauge fields, it gives rise to the magnetic field production together with fermion asymmetry. For example, in the case of U(1) hypergauge field in the Standard Model, we generate B+L asymmetry. In this talk, I will examine the case of U(1) gauged lepton flavor symmetry, which can produce lepton asymmetry. Their...
In scenarios where the dark matter (DM) relic abundance is set by semi-annihilation, two DM particles can produce one dark matter particle and one Standard Model particle. These processes may still occur today in both the Milky Way galaxy and the early Universe, generating a flux of boosted DM particles. We study the resulting signals in direct detection and neutrino experiments for sub-GeV DM...
The Cosmic Neutrino Background (CNB) is a robust thermal relic of the Big Bang and a potential probe of neutrino mass properties and of the Universe at O(1) second. A leading direct-detection strategy is neutrino capture on tritium, where observing a distinct capture peak requires excellent effective energy resolution. In practice, binding and solid-state effects can broaden the endpoint...
We consider the gauged U(1)$_\mathrm{B−L}$ model and examine the situation where the sterile neutrino is a dark matter candidate produced by the freeze-in mechanism. In our model, the dark matter $N$ is mainly produced by the decay of a U(1)$_\mathrm{B−L}$ breaking scalar boson $\phi$. We point out that the on-shell production of $\phi$ through annihilation of the U(1)$_\mathrm{B−L}$ gauge...
Multiple cosmological observations hint at neutrino self-interactions beyond the Standard Model, yet such interactions face severe constraints from terrestrial experiments. We resolve this tension by introducing a model where active neutrinos resonantly convert to self-interacting dark radiation after BBN but before CMB epoch. This exploits the fact that cosmological observables cannot...
The arrival of TeV-energy photons from distant galaxies is expected to be affected by their QED interaction with intergalactic radiation fields through electron-positron pair production. In theories where high-energy photons violate Lorentz symmetry, the kinematics of the process γ + γ → e + + e− is altered and the cross-section suppressed. Consequently, one would expect more of the...
I will talk about a few topics in dark matter physics based on dark U(1) guauge symmetry and dark Higgs boson: (i) two-component WIMP sceario is well alive, (ii) 511 keV line in multi-component DM model, (iii) Belle-II $B^+ \rightarrow K^+ \nu \bar{\nu}$ excess from a light dark sector scenario, (iv) KM3 high energy neutrino events and gravitational wave signatures.
