Spin-Resolved Decay of Axion-Like Particles into Electron--Positron Pairs in Strong Electromagnetic Fields
Abstract
We investigate spin-resolved decay of an axion-like particle (ALP) into an electron--positron pair in an intense laser field. Using the Baier--Katkov quasiclassical operator formalism in a constant crossed field, we derive a compact analytic rate retaining finite ALP-mass effects and the lepton spin degrees of freedom. In the massless limit, the spin-summed rate has the same weak- and strong-field asymptotic scalings as the corresponding photon-induced pair-creation rate, while the pseudoscalar coupling induces distinct spin-resolved channels and spin correlations. A finite ALP mass reorganizes the spectrum across the vacuum threshold, producing purely field-induced pair creation below threshold and spin-dependent oscillatory modulations above threshold through the coherent interplay of vacuum and field-assisted contributions. The entanglement of the produced pair reflects the dominant pair-creation mechanism. After the emission angles have been traced out, the reduced spin state near the vacuum threshold in weak fields is nearly maximally entangled and singlet-like. In the strong-field regime, it becomes triplet-like while retaining a concurrence approaching 1/2, whereas deep in the vacuum-dominated above-threshold regime it becomes triplet-like and separable. These results establish spin-resolved spectra and entanglement as characteristic signatures of finite-mass and threshold effects in strong-field ALP decay.
Versions
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BibTeX
@misc{mao2026spinresolved,
title = {{Spin-Resolved Decay of Axion-Like Particles into Electron--Positron Pairs in Strong Electromagnetic Fields}},
author = {Xiaodan Mao and Yue-Yue Chen and Pei-Lun He},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.14558},
eprint = {2607.14558},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.14558},
}
RIS
TY - UNPB
TI - Spin-Resolved Decay of Axion-Like Particles into Electron--Positron Pairs in Strong Electromagnetic Fields
AU - Xiaodan Mao
AU - Yue-Yue Chen
AU - Pei-Lun He
PY - 2026
DA - 2026/10/19
PB - arXiv
DO - 10.48550/arxiv.2607.14558
UR - https://arxiv.org/abs/2607.14558
AB - We investigate spin-resolved decay of an axion-like particle (ALP) into an electron--positron pair in an intense laser field. Using the Baier--Katkov quasiclassical operator formalism in a constant crossed field, we derive a compact analytic rate retaining finite ALP-mass effects and the lepton spin degrees of freedom. In the massless limit, the spin-summed rate has the same weak- and strong-field asymptotic scalings as the corresponding photon-induced pair-creation rate, while the pseudoscalar coupling induces distinct spin-resolved channels and spin correlations. A finite ALP mass reorganizes the spectrum across the vacuum threshold, producing purely field-induced pair creation below threshold and spin-dependent oscillatory modulations above threshold through the coherent interplay of vacuum and field-assisted contributions. The entanglement of the produced pair reflects the dominant pair-creation mechanism. After the emission angles have been traced out, the reduced spin state near the vacuum threshold in weak fields is nearly maximally entangled and singlet-like. In the strong-field regime, it becomes triplet-like while retaining a concurrence approaching 1/2, whereas deep in the vacuum-dominated above-threshold regime it becomes triplet-like and separable. These results establish spin-resolved spectra and entanglement as characteristic signatures of finite-mass and threshold effects in strong-field ALP decay.
ER -