activity
20242026
collaborators

6 papers

hep-ph2026

Neutron Portal and Dark Matter-Baryon Coincidence: from UV Completion to Phenomenology

Sudhakantha Girmohanta, Yuichiro Nakai, Yoshihiro Shigekami +1

We present a dynamical solution to the dark matter-baryon coincidence problem based on the neutron portal operator connecting the visible and dark sector asymmetries. This framewor…

hep-ph2025

The Minimal Supersymmetric Standard Model with Non-Invertible Selection Rules

Yuichiro Nakai, Hajime Otsuka, Yoshihiro Shigekami +1

We investigate a framework of the Minimal Supersymmetric Standard Model (MSSM) in which the quark and lepton flavor structure and suppression of flavor-changing neutral currents (F…

hep-ph2025

Models for the Electric Dipole Moment and Anomalous Magnetic Moment of the Tau Lepton

Yuichiro Nakai, Yoshihiro Shigekami, Peng Sun +1

The Belle II experiment and other ongoing and projected lepton facilities are expected to greatly enhance the sensitivity to the electric dipole moment (EDM) and anomalous magnetic…

hep-ph2025

Postsphaleron darkogenesis

Sudhakantha Girmohanta, Yuichiro Nakai, Zhihao Zhang

A supercooled phase transition in a nearly conformal dark sector can provide a natural setting for darkogenesis via its out-of-equilibrium dynamics, where a particle-antiparticle n…

hep-th2025

Wiggly dilaton: a landscape of spontaneously broken scale invariance

Sudhakantha Girmohanta, Yuichiro Nakai, Yu-Cheng Qiu +1

The dilaton emerges as a pseudo-Nambu-Goldstone boson (pNGB) associated with the spontaneous breaking of scale invariance in a nearly conformal field theory (CFT). We show the exis…

hep-ph2024

Cold Darkogenesis: Dark Matter and Baryon Asymmetry in Light of the PTA Signal

Kohei Fujikura, Sudhakantha Girmohanta, Yuichiro Nakai +1

We build upon the intriguing possibility that the recently reported nano-Hz gravitational wave signal by Pulsar Timing Array (PTA) experiments is sourced by a strong first-order ph…