Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2610.18334

Cosmological Consequences of a Highly Decoupled Right-handed Neutrino

Stephen F. King·Rishav Roshan·Sudipta Show
View original source ↗Read source document ↗Export metadata ↓

Abstract

In the minimal type-I seesaw, one right-handed neutrino (RHN) can decouple from neutrino mass generation. Such a state is usually neglected, yet its feeble couplings make it long-lived, and it can dominate the energy density of the Universe before decaying. We study this in a minimal $U(1)_{B-L}$ model, where the RHNs are produced through $B-L$ gauge interactions, for the cases of a decoupled lightest RHN $N_1$ and a decoupled heaviest RHN $N_3$. The resulting early matter-dominated era dilutes the baryon asymmetry, and for decoupled $N_3$ it also delays the equilibration of the charged-lepton Yukawa interactions, allowing a lighter $N_1$ to generate the asymmetry in the unflavoured regime. Breaking $U(1)_{B-L}$ forms cosmic strings whose gravitational-wave background acquires a spectral break from the early matter-dominated era, with a frequency set by the decoupled RHN mass and the lightest neutrino mass, within reach of future detectors such as SKA, THEIA, LISA, $μ$ARES, DECIGO and ET.

Explore related subjects

hep-phastro-ph.CO

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Stephen F. King, Rishav Roshan, Sudipta Show. 2026-10-13. Cosmological Consequences of a Highly Decoupled Right-handed Neutrino. https://arxiv.org/abs/2610.18334

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Slow Quanta Bound States and a Possible Link to Dark Matter

We study the possibility of elementary energy quanta with vacuum propagation speed w < c, capable of interacting with each other to form massive bound states. The slow matter thus formed is shown to follow laws of Special Relativity mediated by velocity w rather than c, and to possess dynamical properties recalling some characteristics of Dark Matter.

hep-ph↗
arXiv2026

Topological Diagrams and Hadronic Rescattering: A Framework for CP Violation in Charmed Baryon Decays

Establishing CP violation in the charmed baryon sector remains a central challenge in particle physics. In this work, we develop a framework for CP violation in charmed baryon decays by combining quark-level topological amplitudes with the hadron-level rescattering mechanism. The two descriptions are connected through (1,1)-rank amplitudes, which are linear combinations of topological amplitudes and can be matched directly to the chiral Lagrangian. We verify that the rescattering amplitudes derived from topological amplitudes are consistent with those obtained directly from the chiral Lagrangian and show explicitly that the isospin sum rules are preserved. The $u$-, $t$-, and $s$-channel rescattering amplitudes contributing to each (1,1)-rank amplitude in the $SU(3)_F$ limit are derived. It is found that the long-distance rescattering contributions to quark-loop amplitudes can be related to those of tree amplitudes without introducing additional nonperturbative parameters. We perform global fits to available branching-fraction and decay-parameter data and predict the CP asymmetries in charmed baryon decays. The $Λ^+_c\to pη^\prime$ mode, with a predicted CP asymmetry of order $10^{-3}$, is identified as a promising channel for CP violation searches in charmed baryon sector. We also suggest measuring more observables in $Ξ^0_c$ decay modes to reduce the uncertainties in the CP violation predictions. In addition, the Körner-Pati-Woo theorem is found to be in tension with rescattering dynamics, casts doubt on the validity of its conventional proof. A precise measurement of the branching fraction of the $Λ^+_c\to Σ^+K^0_S$ mode would provide a stringent test the Körner-Pati-Woo theorem.

hep-ph↗
arXiv2026

Critical properties of bound states with one-boson-exchange potential

In this study, we discuss some general critical properties of bound states with one-boson-exchange potential. For simplicity, we first take a system with two identical scalar particles as an example. The interaction between these two scalar particles is described by the exchange of another massive scalar meson under the instantaneous approximation, which results in the Yukawa potential. A highly accurate numerical method is used to determine the critical mass value of the system. The resulting critical mass for the ground state is consistent with those reported in the literature, agreeing to about 35 significant figures. The highly accurate results for the $l=1$ case are also presented, which are significantly more precise than those previously reported in the literature. Furthermore, we extend the discussion to physical hadronic molecular states, where form factors are introduced in the interaction to describe the structure of hadrons. Our numerical results show that although the binding energies of the hadronic molecular states depend on the cutoff in the form factors, the number of hadronic molecular states is almost independent of the cutoffs across a very wide physical region. This indicates a strong and important property: for physically small couplings, the number of hadronic molecular states is almost solely determined by the coupling constants and the masses of the exchange particles. This highly accurate numerical method can also be straightforwardly applied to higher $l$ cases or other systems.

hep-ph↗