Millicharged particles weaken pulsational pair-instability in massive stars, shifting the lower edge of the black hole mass gap upward and turning gravitational wave observations into a probe for particles with masses 35-200 keV and charges 10^{-10} to 10^{-9}.
Axion-photon conversion in transient compact stars: Systematics, constraints, and opportunities
4 Pith papers cite this work. Polarity classification is still indexing.
abstract
We study magnetic conversion of ultra-relativistic axion-like particles (ALPs) into photons in compact-star environments, focusing on the hot, transient conditions of core-collapse supernova (SN) remnants and neutron-star mergers (NSMs). We address previously overlooked uncertainties, particularly the suppression caused by ejected matter near the stellar surface, a region crucial to the conversion process. We derive analytical expressions for the transition rate; they reveal the influence of key parameters and their uncertainties. We update constraints using historical gamma-ray data from SN~1987A and find $g_{a\gamma}<5\times10^{-12}~{\rm GeV}^{-1}$ for $m_a\lesssim10^{-9}$ eV. We also forecast sensitivities for a future Galactic SN and for NSMs, assuming observations with Fermi-LAT or similar gamma-ray instruments. We distinguish ALPs -- defined as coupling only to photons and produced via Primakoff scattering -- from axions, which also couple to nucleons and emerge through nuclear bremsstrahlung. We omit pionic axion production due to its large uncertainties and inconsistencies, though it could contribute comparably to bremsstrahlung under optimistic assumptions. For the compact sources, we adopt time-averaged one-zone models, guided by numerical simulations, to enable clear and reproducible parametric studies.
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Axions produced in supernovae generate a diffuse gamma-ray signal through conversion in magnetic fields, yielding competitive constraints on the axion-photon coupling from COMPTEL, EGRET, and Fermi-LAT data plus forecasts for future MeV telescopes.
Stripped-envelope supernovae enable QCD axion detection to masses around 10^{-4} eV via gamma-ray signals from conversion in progenitor magnetic fields.
Turbulent magnetic fields enhance axion-photon conversion signals from supernovae, improving limits on axion-proton and axion-photon couplings by up to two orders of magnitude.
citing papers explorer
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The Black Hole Mass Gap as a New Probe of Millicharged Particles
Millicharged particles weaken pulsational pair-instability in massive stars, shifting the lower edge of the black hole mass gap upward and turning gravitational wave observations into a probe for particles with masses 35-200 keV and charges 10^{-10} to 10^{-9}.
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Lights, Camera, Axion: Tracing Axions from Supernovae in the Diffuse $\gamma$-ray Sky
Axions produced in supernovae generate a diffuse gamma-ray signal through conversion in magnetic fields, yielding competitive constraints on the axion-photon coupling from COMPTEL, EGRET, and Fermi-LAT data plus forecasts for future MeV telescopes.
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Stripped-Envelope Supernovae for QCD Axion Detection
Stripped-envelope supernovae enable QCD axion detection to masses around 10^{-4} eV via gamma-ray signals from conversion in progenitor magnetic fields.
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Magnetic Turbulence Boosts Supernova Signals of Axion-Photon Conversion
Turbulent magnetic fields enhance axion-photon conversion signals from supernovae, improving limits on axion-proton and axion-photon couplings by up to two orders of magnitude.