We introduce the scattering of a scalar field in the black hole spacetime. Based on our recent studies, various sides of a black hole are presented. When a scalar field is scattered by a black hole, there are fluxes going into the black hole. From the fluxes of the scalar field flowing into the black hole, the changes in mass and angular momenta of the black hole are obtained. These can affect...

Zoom talk

Time: Feb 20, 2024 04:00 PM Seoul

https://cau.zoom.us/j/83446216531?pwd=L3FFMTBmN1hlNUdXSFA0WGlWeWM1dz09

Meeting ID: 834 4621 6531

Passcode: CAUBSM

In this talk, I will introduce the Big Bang nucleosynthesis (BBN) constraint on the majoron-like particle in the mass range between 1MeV to 10GeV which dominantly decays into the standard model neutrinos. For a lifetime shorter than 1 sec, the majoron heats up the background plasma by injecting neutrinos and changes the relation of photon temperature and background neutrino temperature,...

I will discuss the halo-independent bounds on the WIMP-nucleon couplings of the non-relativistic effective Hamiltonian that drives the scattering process off nuclei of a WIMP of spin 1/2 combining direct detection experiments and neutrino telescopes data in order to cover the full WIMP incoming speed range.

In the elastic interactions, for most of the couplings the degree of relaxation of...

We will introduce 'Lattice Cosmology' techniques and explain how these can be used to solve non-linear dynamics of interactive fields in an expanding Universe. As a demonstration of these ideas we apply them to solve three different problems of early Universe cosmology: i) the non-linear dynamics of axion inflation, iii) the dynamics and gravitational wave emission of string loops, and if time...

Zoom talk

Time: Feb 21, 2024 04:00 PM Seoul

https://cau.zoom.us/j/82398189490?pwd=VkpWSEpqVGh5Vnc1ODRhZmdtdGRUdz09

Meeting ID: 823 9818 9490

Passcode: CAUBSM

Motivated by the recent release of new results from five different pulsar timing array (PTA) experiments claiming to have found compelling evidence for primordial gravitational waves (GW) at nano-Hz frequencies, we consider the prospects of generating such a signal from inflationary blue-tilted tensor power spectrum in a specific dark matter (DM) scenario dubbed as Miracle-less WIMP. While...

We investigate Euclidean wormholes and their cosmological implications. Generically it was known that the Euclidean compact instantons explain the Bunch-Davies vacuum. If we make the assumption weeker and consider the Euclidean wormholes, we have the freedom to choose another vacuum condition. If we impose the de Sitter invariance condition, we can conclude that the Euclidean wormholes can be...

A recent theory work on new physics search in the B->D*l nu decay (including Vcb puzzle etc) will be discussed.

The Belle II collaboration recently announced that they observed the B+ → K+νν decay process for the first time. This dineutrino mode of B+ → K+νν has been theoretically identified as a very clean channel. However, their result encounters a 2.8σ deviation from the Standard Model (SM) calculation. On the other hand, last year, Fermilab released new data on muon (g − 2) away from the SM...

Invisible and semi-invisible decays of mesons are good tools for testing dark matter models. In particular, we consider the possibility to study dark photon model parameter space in experiments at fixed target (for NA64 and other). We discuss limits from fixed target experiments using leptonic or hadronic beams.

We study the phenomenology of leptophilic $Z'$ gauge bosons at the future high-energy $e^+e^-$ or $\mu^+\mu^-$ colliders. The leptophilic $Z'$ model remains largely unconstrained from current low-energy and collider searches for $Z'$ masses above ${\cal O}(100~{\rm GeV})$, thus providing a unique opportunity for future lepton colliders. Taking leptophilic...

We propose a minimal scenario for light thermal dark matter (DM) in sub-GeV to GeV ballpark by incorporating a scalar singlet DM in a type-I seesaw scenario extended by an additional Higgs doublet ϕ2. The latter permits efficient annihilation of light scalar DM into leptonic final states including right-handed neutrinos (RHN). While DM annihilation into charged lepton final states is kept...

In this talk I will discuss how the Weakly Interacting Massive Particle (WIMP) thermal decoupling scenario can be used to probe Cosmologies in dilatonic Einstein Gauss-Bonnet (dEGB) gravity, where the Gauss–Bonnet term is non–minimally coupled to a scalar field with vanishing potential. Constraints on the model parameters can be obtained when the ensuing modified cosmological scenario drives...