Axion emission from supernova with axion-pion-nucleon contact interaction

Abstract

We examine the axion emission from supernovae with a complete set of relevant axion couplings including the axion-pion-nucleon contact interaction which was ignored in the previous studies. Two processes are affected by the axion-pion-nucleon contact interaction, π− + p → n + a and n + p → n + p + a, and these processes can be the dominant source of axions for some region in the axion parameter space or in astrophysical conditions encountered inside supernovae. We find that the contact interaction can enhance the axion emissivity of π− + p → n + a by a factor of 2 − 4, while the effect on n + p → n + p + a is not significant. We also discuss the relative importance of other pion-induced processes such as π0 + n → n + a and π− + π0→ π− + a.

Astrophysical Axion Bounds: The 2024 Edition

“…In analogy to axions, for completeness, we also report here the standard-model nucleon-pion interactions [41,46]…”

“…The nucleon-pion and nucleon-axion couplings allow for processes such as 𝜋 + 𝑁 → 𝑁 + 𝑎. In addition, there is also a direct pion-nucleon-axion vertex [41,46,48]…”

“…In nonrelativistic 𝑁 𝑁 bremsstrahlung, this direct coupling is subdominant, but matters in 𝜋𝑁 → 𝑁𝑎. Such processes can be particularly relevant for supernova axions, both for their production and for their detection on Earth [46,[49][50][51].…”

“…In another calculation of the pionic emission rate [46], the direct axion-pion-nucleon vertex Eq. ( 11) was included.…”

Dark gauge boson production from neutron stars via nucleon-nucleon bremsstrahlung

“…A stringent constraint emerges from the measurement of the neutrino flux of SN1987A [2][3][4] : the time duration of the bulk neutrino flux, which is fitted by the simulations [5][6][7], could be reduced by an extra cooling. Taking into account the well established criterion for SN1987A that novel particle emissions cannot go over the limit of 3 × 10 52 erg s −1 [1], one can derive the strong constraint on new particles such as axions [8][9][10][11][12][13][14][15][16] and dark gauge bosons [17][18][19][20]. Furthermore, young NS with ages under 10 4 -10 5 yr are also of interest in terms of the stellar cooling argument since they still possess a vigorous thermodynamic energy inside with a little contamination from any heating sources if it is well isolated.…”