Probe of Solar Neutrino Magnetic Moments through Spin-Flavor Precession: Resonance Structure and Antineutrino Appearance
Abstract
We investigate solar-neutrino spin--flavor precession (SFP) induced by magnetic moments in the three-active-flavor framework. For Majorana neutrinos, SFP can convert solar neutrinos into antineutrinos of different active flavors. In the Dirac case, SFP instead produces sterile right-handed states and can lead to the disappearance of active neutrinos. Using the full 6×6 Hamiltonians and GS98 and AGSS09 solar profiles, we examine propagation-eigenvalue crossings at B⊥=0 and the projected magnetic couplings between the corresponding states. For normal mass ordering and 1≤ Eν/MeV≤20, we confirm the absence of finite-density Majorana crossings. A magnetically coupled Dirac crossing emerges above approximately 12 MeV but involves only a subdominant electron-flavor component, limiting resonant disappearance. Nonresonant Majorana conversion nevertheless offers a distinctive lepton-number-violating solar ν̅e signal, motivating our sensitivity study for the Jinping Neutrino Experiment. For a proposed 3 kt detector operating for five to ten years, we project a 90\% C.L. sensitivity of P(νe→ν̅e)≃(0.85−1.3)×10−5. In the μ12-only benchmark, optimistic solar-core transverse magnetic fields of B⊥=7−10 MG imply a reach of |μ12|≃(2.3−4.1)×10−13 μB, numerically below existing direct-scattering limits and commonly quoted stellar-cooling bounds. This could enable Jinping to provide one of the most stringent projected terrestrial sensitivities to Majorana transition magnetic moments.
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BibTeX
@misc{bakhti2026probe,
title = {{Probe of Solar Neutrino Magnetic Moments through Spin-Flavor Precession: Resonance Structure and Antineutrino Appearance}},
author = {Pouya Bakhti and Sudip Jana and Chui-Fan Kong and Seodong Shin and Seokhoon Yun},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.14446},
eprint = {2609.14446},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.14446},
note = {CC0},
}
RIS
TY - UNPB
TI - Probe of Solar Neutrino Magnetic Moments through Spin-Flavor Precession: Resonance Structure and Antineutrino Appearance
AU - Pouya Bakhti
AU - Sudip Jana
AU - Chui-Fan Kong
AU - Seodong Shin
AU - Seokhoon Yun
PY - 2026
DA - 2026/09/13
PB - arXiv
DO - 10.48550/arxiv.2609.14446
UR - https://arxiv.org/abs/2609.14446
AB - We investigate solar-neutrino spin--flavor precession (SFP) induced by magnetic moments in the three-active-flavor framework. For Majorana neutrinos, SFP can convert solar neutrinos into antineutrinos of different active flavors. In the Dirac case, SFP instead produces sterile right-handed states and can lead to the disappearance of active neutrinos. Using the full 6×6 Hamiltonians and GS98 and AGSS09 solar profiles, we examine propagation-eigenvalue crossings at B_⊥=0 and the projected magnetic couplings between the corresponding states. For normal mass ordering and 1≤ E_ν/MeV≤20, we confirm the absence of finite-density Majorana crossings. A magnetically coupled Dirac crossing emerges above approximately 12 MeV but involves only a subdominant electron-flavor component, limiting resonant disappearance. Nonresonant Majorana conversion nevertheless offers a distinctive lepton-number-violating solar ν̅_e signal, motivating our sensitivity study for the Jinping Neutrino Experiment. For a proposed 3 kt detector operating for five to ten years, we project a 90\% C.L. sensitivity of P(ν_e→ν̅_e)≃(0.85−1.3)×10^−5. In the μ_12-only benchmark, optimistic solar-core transverse magnetic fields of B_⊥=7−10 MG imply a reach of |μ_12|≃(2.3−4.1)×10^−13 μ_B, numerically below existing direct-scattering limits and commonly quoted stellar-cooling bounds. This could enable Jinping to provide one of the most stringent projected terrestrial sensitivities to Majorana transition magnetic moments.
ER -