Neutrino Electroweak Couplings and the Neutrino Fog at Belle II
Abstract
The mono-photon process e+e- → γ+invisible at Belle II probes both invisible new states and the electroweak couplings of neutrinos. In this work, we study the process e+e- → γνν̅, finding that Belle II with the full expected dataset can determine the neutrino-sensitive effective weak mixing angle to a 3.6% relative statistical precision, competitive with existing neutrino probes at other energy scales. Polarized beams, as proposed for the Chiral Belle upgrade, separate the neutral- and charged-current contributions and provide independent access to each, giving a handle on the chiral structure of the neutrino gauge interactions. The same process is an irreducible background to dark boson searches, producing a neutrino fog once the luminosity exceeds 1 ab−1.
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BibTeX
@misc{lima2026neutrino,
title = {{Neutrino Electroweak Couplings and the Neutrino Fog at Belle II}},
author = {Carlos Henrique de Lima and David McKeen and Afif Omar and Douglas Tuckler},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.00121},
eprint = {2609.00121},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.00121},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Neutrino Electroweak Couplings and the Neutrino Fog at Belle II
AU - Carlos Henrique de Lima
AU - David McKeen
AU - Afif Omar
AU - Douglas Tuckler
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2609.00121
UR - https://arxiv.org/abs/2609.00121
AB - The mono-photon process e^+e^- → γ+invisible at Belle II probes both invisible new states and the electroweak couplings of neutrinos. In this work, we study the process e^+e^- → γνν̅, finding that Belle II with the full expected dataset can determine the neutrino-sensitive effective weak mixing angle to a 3.6% relative statistical precision, competitive with existing neutrino probes at other energy scales. Polarized beams, as proposed for the Chiral Belle upgrade, separate the neutral- and charged-current contributions and provide independent access to each, giving a handle on the chiral structure of the neutrino gauge interactions. The same process is an irreducible background to dark boson searches, producing a neutrino fog once the luminosity exceeds 1 ab^−1.
ER -