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This study examines how stellar rotation affects constraints on axion-like particles (ALPs) derived from supernova SN 1987A observations. Using two-dimensional simulations of rotating stellar cores, researchers found that rotation suppresses ALP emission more effectively than neutrino emission by reducing core temperatures through centrifugal support, thereby relaxing energy-loss-based constraints on ALP properties. However, rotation has minimal impact on constraints derived from gamma-ray observations because these constraints depend on the fourth power of the ALP-photon coupling constant, making them relatively insensitive to emission rate changes.
Why it matters
These findings suggest that previous constraints on axion-like particles from supernova observations may need revision when accounting for realistic stellar rotation. This has implications for experimental searches for ALPs and other beyond-standard-model particles, potentially expanding the viable parameter space for new physics.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Abstract: We study how rotation modifies the constraints on MeV-scale axion-like particles (ALPs) coupled to photons derived from SN 1987A. We constrain the ALP parameter space based on both the energy-loss argument and the gamma-ray limits, and examine how these constraints are affected by stellar rotation. Adopting initial angular velocities of ${Omega}_{0} = 0.0 and 1.0 rad s^{-1}$ in the iron core, we carry out two-dimensional core-collapse supernova simulations for three progenitor models – a $14 + 9M_{odot}$ binary and $13M_{odot}$ and $18M_{odot}$ single stars with solar metallicity – and estimate ALP emission rates through post-processing. We find that rotation suppresses ALP emission by reducing the core temperature via centrifugal support. Rotation also reduces the neutrino luminosity, but the suppression of ALP emission is more effective, leading to relaxed constraints within a simplified criterion based on the energy-loss argument. This relaxation is particularly pronounced in the rotating $18M_{odot}$ model, where a substantial decrease in the central temperature occurs at $t_{pb} = 0.8 – 1 s$. In this simplified criterion, such rapid temporal variations in temperature indicate that the resulting constraints depend sensitively on both the evaluation time and the underlying supernova model. For a gamma-ray limit from the SN 1987A observation, rotation has a negligible impact on the constraint. This is because the ALP-induced gamma-ray fluence observed at Earth is proportional to the fourth power of the ALP-photon coupling constant, making the constraint relatively insensitive to the rotational suppression of ALP emission.
Source: Rotation-induced Relaxation of Supernova Constraints on Axionlike Particles