dorsal/arxiv
View SchemaNaturally small Dirac neutrino mass and $B-L$ dark matter
| Authors | Ernest Ma, Partha Kumar Paul, Narendra Sahu |
|---|---|
| Categories | |
| ArXiv ID | 2601.05926vv1 |
| URL | https://arxiv.org/abs/2601.05926 |
| License | http://creativecommons.org/licenses/by/4.0/ |
Abstract
In the conventional gauged ${B-L}$ extension of the standard model, the $B-L$ charge of the singlet scalar $\chi$, responsible for the breaking of $U(1)_{B-L}$ symmetry, is taken to be 2 such that it can anchor type-I seesaw by giving Majorana masses to the right-handed neutrinos, $\nu_R$. In this paper, we consider instead the cases $\chi \sim 3$ or 4 under $B-L$, so that $\nu_R$ may not acquire any Majorana mass and neutrinos are Dirac fermions. We then consider a vector-like fermion $S$ with 2 units of $B-L$ charge, which becomes a good candidate for dark matter, either Dirac for $\chi \sim 3$ or Majorana for $\chi \sim 4$. In both cases, spontaneous $B-L$ breaking can induce a strong first-order phase transition, producing stochastic gravitational waves (GW) which can be tested at GW experiments. Moreover, the presence of light $\nu_R$s gives rise to an additional contribution to the effective number of relativistic degrees of freedom, $\Delta{N}_{\rm eff}$, providing complementary constraints from current and upcoming CMB observations.
{
"annotation_id": "6c1b8c5f-3ea4-41e1-907a-9ef95ed1ec4a",
"date_created": "2026-02-17T05:53:04.714000Z",
"date_modified": "2026-02-17T05:53:04.714000Z",
"file_hash": "1f626f397222084c0f1ac3aed3767826aa12aec4bd29c3279da97e1402675f94",
"private": false,
"record": {
"abstract": "In the conventional gauged ${B-L}$ extension of the standard model, the $B-L$ charge of the singlet scalar $\\chi$, responsible for the breaking of $U(1)_{B-L}$ symmetry, is taken to be 2 such that it can anchor type-I seesaw by giving Majorana masses to the right-handed neutrinos, $\\nu_R$. In this paper, we consider instead the cases $\\chi \\sim 3$ or 4 under $B-L$, so that $\\nu_R$ may not acquire any Majorana mass and neutrinos are Dirac fermions. We then consider a vector-like fermion $S$ with 2 units of $B-L$ charge, which becomes a good candidate for dark matter, either Dirac for $\\chi \\sim 3$ or Majorana for $\\chi \\sim 4$. In both cases, spontaneous $B-L$ breaking can induce a strong first-order phase transition, producing stochastic gravitational waves (GW) which can be tested at GW experiments. Moreover, the presence of light $\\nu_R$s gives rise to an additional contribution to the effective number of relativistic degrees of freedom, $\\Delta{N}_{\\rm eff}$, providing complementary constraints from current and upcoming CMB observations.",
"arxiv_id": "2601.05926",
"authors": [
"Ernest Ma",
"Partha Kumar Paul",
"Narendra Sahu"
],
"categories": [
"hep-ph",
"astro-ph.CO"
],
"license": "http://creativecommons.org/licenses/by/4.0/",
"title": "Naturally small Dirac neutrino mass and $B-L$ dark matter",
"url": "https://arxiv.org/abs/2601.05926",
"version": "v1"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "afa4985c-0596-4ede-9a9e-29db467395c2",
"id": "arXiv Dataset",
"type": "Model",
"variant": "snapshot-2026-01-17",
"version": "0.1.0"
},
"user_id": 1000002
}