Nobuchika Okada

The shape of quark flavors

Shinsuke Kawai, Nobuchika Okada

We construct the Yukawa couplings of the quark sector as overlap integrals of Gaussian wave functions in extra spatial dimensions. Assuming that the wave function of each chiral fe…

A Model-Independent Approach to First-Order Phase Transitions, Gravitational Waves, and Primordial Magnetic Fields

Fayez Abu-Ajamieh, Nobuchika Okada

We employ a model-independent Effective Field Theory (EFT) to analyze the possibility of a strong First-Order Phase Transition (FOPT) in extensions Beyond the Standard Model (BSM).…

Disentangling new physics with quantum entanglement in $t t ˉ$ production at future lepton colliders

Masato Arai, Kentarou Mawatari, Nobuchika Okada

We investigate quantum entanglement and Bell-inequality violation in top-antitop pair production at future lepton colliders such as the International Linear Collider (ILC) and mult…

Signatures of Long-Lived Heavy Neutral Leptons from Neutrinophilic Charged Higgs Pair Production at the LHC

Nobuchika Okada, Prasenjit Sanyal, Ravindra Kumar Verma

In the neutrinophilic Higgs doublet framework, the neutrino Dirac Yukawa couplings can be sizable because of the small vacuum expection value of the extra Higgs doublet, even for a…

Discovery prospects of a singly-charged scalar at $μ$ TRISTAN

Joseph George, Nobuchika Okada, Dibyashree Sengupta +1

In this article, we study the associated production of a singly-charged ( $Δ^{+}$ ) scalar along with a $W^{+}$ boson in the newly proposed $μ^{+} μ^{+}$ collider (also known as $μ$ TRISTAN) a…

Good flavor search in SU(5): a machine learning approach

Fayez Abu-Ajamieh, Shinsuke Kawai, Nobuchika Okada

We revisit the fermion mass problem of the $S U (5)$ grand unified theory using machine learning techniques. The original $S U (5)$ model proposed by Georgi and Glashow is incompatible…

Novel Bounds From The Weak Gravity and Festina Lente Conjectures

Fayez Abu-Ajamieh, Pratik Chattopadhyay, Nobuchika Okada +2

We demonstrate that the Weak Gravity Conjecture (WGC) and the Festina-Lente Conjecture (FLC) yield novel bounds on fifth force searches and milli-Charged Particles (mCPs), as well…

Complementarity between gravitational wave signatures and Higgs precision measurements of a classically conformal hidden U(1) extended Standard Model

Victor Baules, Nobuchika Okada

We consider a classically conformal extension of the Standard Model (SM) with a hidden $U (1)$ gauge symmetry, where the $U (1)$ symmetry is radiatively broken via the Coleman-Weinbe…

Impact of Non-Thermal Leptogenesis with Early Matter Domination on Gravitational Waves from First-order Phase Transition

Dilip Kumar Ghosh, Anish Ghoshal, Koustav Mukherjee +2

We study the impact of non-thermal leptogenesis on the spectrum of gravitational waves (GWs) produced by a strong first-order phase transition in the early Universe. We consider a…

Novel and Updated Bounds on Flavor-Violating Z Interactions in the Quark Sector

Fayez Abu-Ajamieh, Amine Ahriche, Suman Kumbhakar +1

We derive bounds on the flavor-violating (FV) couplings of the $Z$ boson to quarks and present future sensitivity projections. Our analysis shows that the current bounds on the FV…

astro-ph.CO2025

Kination-like Era Driven by the Effective Inflaton/Higgs Potential

Anish Ghoshal, Nobuchika Okada, Arnab Paul

Based on the minimal $U (1)_{X}$ extended Standard Model, we explore cosmic inflation where the $U (1)_{X}$ Higgs field serves as the inflaton. We demonstrate that a stiff era with an eq…

Novel and Updated Bounds on Flavor-violating Z Interactions in the Lepton Sector

Fayez Abu-Ajamieh, Amine Ahriche, Nobuchika Okada

We investigate the experimental bounds on the Flavor-Violating (FV) couplings of the $Z$ boson to the charged leptons. In addition to the direct LHC searches for FV $Z$ decays to l…

Truth, beauty, and goodness in grand unification: a machine learning approach

Shinsuke Kawai, Nobuchika Okada

We investigate the flavour sector of the supersymmetric $S U (5)$ Grand Unified Theory (GUT) model using machine learning techniques. The minimal $S U (5)$ model is known to predict fe…

Aspects of Non-local QED and the Weak Gravity Conjecture

Fayez Abu-Ajamieh, Nobuchika Okada, Sudhir K. Vempati

We use the Weak Gravity Conjecture (WGC) to investigate the impact of charge dequantization arising from non-local QED on the scale of non-locality of neutrinos. We find this scale…

astro-ph.CO2024

Unified Origin of Curvature Perturbation and Baryon Asymmetry of the Universe

Anish Ghoshal, Abhishek Naskar, Nobuchika Okada

We propose a unified framework that describes both the curvaton mechanism for generating primordial density fluctuations and the Affleck-Dine (AD) mechanism for baryogenesis. By in…

Non-perturbative Origin of the Electroweak Scale with Dyson-Schwinger: Fermionic Mass Gap and Higher-order Excitations

Marco Frasca, Anish Ghoshal, Nobuchika Okada

We study interaction of a fermion field $ψ$ with a scalar field $ϕ$ and analyze the spectrum of the theory obtained in this way. It is shown that due to non-perturbative dynamics i…

Non-perturbative Origin of Electroweak Scale via Higgs-portal: Dyson-Schwinger in Conformally Invariant Scalar Sector

Marco Frasca, Anish Ghoshal, Nobuchika Okada

We investigate conformally extended Standard Model with a hidden scalar $ϕ$ . It is shown that due to non-perturbative dynamics in the hidden sector, $ϕ$ develops a vacuum expectati…

The Generalized Scalar Weak Gravity Conjecture and its Implications

Fayez Abu-Ajamieh, Nobuchika Okada, Sudhir K. Vempati

We propose a generalized formulation of the Scalar Weak Gravity Conjecture (SWGC) based on the analogy with the derivation of the Gauge Weak Gravity Conjecture (GWGC). We discuss s…

astro-ph.CO2024

Double Inflation in Classically Conformal $B - L$ Model

Anish Ghoshal, Nobuchika Okada, Arnab Paul +1

It has recently been shown in Ref. [1] that the double-inflation scenario based on the Coleman-Weinberg potential can successfully generate primordial black holes (PBHs) with the i…

Non-perturbative Origin of the Electroweak Scale: RGE in Strongly-coupled Dark Gauge Theories via Dyson-Schwinger

Marco Frasca, Anish Ghoshal, Nobuchika Okada

We propose a novel pathway to generate the electroweak scale (EW) via non-perturbative dynamics of a dark gauge sector based on the SU(N) gauge group. Imposing the scale invariance…