We propose to discuss the modular flavor model and the stabilization of single modulus field in the Jordan frame supergravity with non-minimal scalar-curvature coupling. Modular invariance and positivity of the scale factor constrain stringently the form of the frame function, consequently the Kahler potential. We discuss some general properties of scalar potentials after the scale...
Modular symmetry is a promising framework for flavor physics, where Yukawa couplings are described by modular forms. After a brief introduction to the basic idea, this presentation focuses on the behavior of modular forms near a fixed point and discusses how their general properties can shed light on lepton flavor structure
The concept of prominence is familiar to signal engineers, topographers and mountaineers. I will introduce prominence as a discriminator of gravitational wave signals.
We investigate the stochastic gravitational-wave background produced by metastable cosmic strings in a minimal $SU(2) \times U(1)$ dark sector. We demonstrate that a single-scale framework featuring a single Higgs field is sufficient to explain the signal reported by Pulsar Timing Arrays. By calculating the string decay rate via monopole nucleation within the thin-defect approximation, we...
The spontaneous breaking of an $A_4$ flavour symmetry can lead to the formation of domain walls. We study this phenomenon in the scenarios of real and complex $A_4$ symmetric scalar theories and discover new kinds of domain walls, which we denote as ``oreo''-type composite domain walls and CP-violating domain walls.
$SU(5)$ grand unified model, which unifies SM quarks and leptons in $\overline{5}$ and $10$ dimensional irreducible representations, yields observationally inconsistent tree-level Yukawa relations when only a single $5_{\rm H}$ or $45_{\rm H}$ dimensional irrep having a single Higgs contributes to the Yukawa sector. For instance, only $5_{\rm H}$ dimensional Higgs in the Yukawa sector yields...
We investigate type-I seesaw frameworks motivated by Grand Unification, focusing on the generic consequences of hierarchical Dirac neutrino masses as expected in many SO(10)-type constructions where neutrino Yukawa couplings are linked to the up-quark sector. Excluding the well-known highly fine-tuned crossing-level solutions and using current low-energy neutrino data, we show that these...
It is common practice to explain deviations between data and Standard-Model (SM) predictions by postulating new particles at the TeV scale ad-hoc. This approach becomes much more convincing, if one successfully embeds the postulated particles into a UV completion which addresses other conceptual or phenomenological shortcomings of the SM. We present a study of an SO(10) grand unified theory...
We know from the discovery of the Higgs boson that electroweak symmetry is broken through the Higgs mechanism, but we expect this should be restored at high temperatures in the early universe. Thus we believe the matter in the universe underwent a dramatic change of state as the universe cooled down. Electroweak phase transitions have many important consequences, for example if strongly first...
First-order phase transitions in the early Universe are a well-motivated source of gravitational waves. In this talk, I will discuss a previously overlooked gravitational wave production mechanism: gravitational transition radiation, arising from graviton emission by particles whose mass changes as they pass through expanding bubble walls. The resulting spectrum features a distinctive shape...
In my talk I will focus on renormalizable and ghost-free quantum gravity proposals. An important feature of these models is the presence of infinite derivative operators. Such models on contrary to local gravity modifications can give a blue tilted spectrum of primordial GWs while local models uniquely predict a red tilted primordial GWs spectrum. This is an essential possible observational...
I will discuss the cosmology of a brane-world realization of massive gravity. The theory, known as warped massive gravity, postulates the existence of dRGT potentials in the 5D bulk and in the 4D brane, and has the virtue of raising the strong-coupling scale of the 4D theory. Although generically the 4D dynamics cannot be decoupled from the bulk equations, we identify, in the cosmological...
We investigate a range of non-singular cosmological scenarios within the framework of Horndeski gravity. In particular, we construct a bouncing Universe model and propose a minimal setup that realizes a non-pathological Genesis scenario. Both constructions allow for a fully stable transition to the kination epoch, during which General Relativity (GR) is restored. These scenarios successfully...
We explore two major approaches to the strong CP problem, the axion solution and spontaneous CP violation (SCPV). We first focus on composite axion models, which provide a compelling realization of the axion solution but face serious cosmological challenges, in particular the domain wall problem. We present a new framework based on a special embedding of gauge symmetries, where the domain wall...
Realistic E6 GUTs were proposed in recent years with nice and peculiar features like the existence of a dark matter candidate and/or a correct Yukawa structure. The price to pay in such models is the use of large representations of the E6 group, which make the theory UV non-free with a Landau pole less than one order of magnitude above the GUT scale. I will present in this talk an E6 model...
We present the idea of asymptotic grand unification, where the gauge couplings run to a unique fixed point in the ultraviolet, thanks to the presence of a compact extra dimension and to a specific choice group structure and multiplet content. We introduce a minimal model based on a SU(5) gauge theory but also discuss SO(10) and other generalisations, giving also few results on the expected...
Asymptotic grand unification (aGUT) replaces conventional fixed-scale unification by ultraviolet-safe flows toward a common interacting fixed point. Five-dimensional orbifold gauge theories are a natural arena for aGUT model building, but viability requires both a stable orbifold vacuum and consistent UV fixed points. I present general stability criteria for gauge breaking on...
We provide a systematic construction of three-family N=1 supersymmetric Pati-Salam models from Type IIA orientifolds on T^6/(Z_2 × Z_2) with intersecting D6-branes. All the gauge symmetries SU(4)_C × SU(2)_L × SU(2)_R arise from the stacks of D6-branes with U(n) gauge symmetries, while the hidden sector is specified by USp(n) D6-branes. The Pati-Salam gauge symmetry can be broken down to the...
Non-invertible symmetries have recently provided new possibilities for particle-physics model building. In this talk, I will discuss two examples based on non-invertible selection rules in lepton physics. The first is a radiative lepton model based on the Ising fusion rule, where the charged-lepton mass hierarchy is partially generated through one-loop dynamical symmetry breaking, while...
We propose an extension of the standard model (SM) by two SU (2) triplet scalars and an inert SU (2) doublet. We demonstrate that this setup can simultaneously produce an inflaton and baryon asymmetry in the early universe, provide a dark matter candidate and explain the smallness of neutrino masses. The required CP -violation for lepton asymmetry is obtained by interference between the...
I will discuss the potential neutrino telescopes will have for probing dark matter particle models. I will present recent work with the TRIDENT collaboration where we project the experiments future sensitivity to annihilating DM. We project that TRIDENT is on track to reach annihilation rates below the thermal freeze-out benchmark for dark matter masses between 1-100 TeV. However, I will...
We investigate the possibility of baryogenesis scenarios where the evaporation of the primordial black holes (PBHs) formed in the early universe can be sources of the matter-genesis in the universe. The PBHs evaporate before the Big-bang nucleosynthesis as their mass is below 10^9 g, and no PBH remains in the current universe. Even if the plasma temperature is well below the particle mass,...
The Affleck–Dine mechanism is a leading baryogenesis scenario in which scalar condensates form coherently during inflation along supersymmetric flat directions that are lifted by supersymmetry-breaking effects. We update the viable parameter space for baryogenesis using recent Cosmic Microwave Background constraints on baryon-density isocurvature perturbations, taking the quantum fluctuations...
I discuss production of very weakly interacting or free particles in the Early Universe. Due to inflation and postinflationary dynamics such particles are produced copiously even in the absence of any non-gravitational couplings. This phenomenon has important implications for dark matter physics.
We consider the gauged $\mathrm{U(1)_{B−L}}$ 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 $\mathrm{U(1)_{B-L}}$ breaking scalar boson $\phi$. We point out that the on-shell production of $\phi$ through annihilation of the $\mathrm{U(1)_{B-L}}$...
GUTs unify quarks and leptons into same representations and predict correlations between their masses and mixing. We perform numerical scans in SO(10) GUTs to explore the flavor space with new data of JUNO taken into account. The quark-lepton correlation shows the preference of normal ordering for light neutrino masses, predicts favored region of the CP-violating phase in neutrino...
