| 1. |
- Calore, Francesca, et al.
(author)
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3D template-based Fermi-LAT constraints on the diffuse supernova axion-like particle background
- 2022
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In: Physical Review D. - 2470-0010 .- 2470-0029. ; 105:6
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Journal article (peer-reviewed)abstract
- Axion-like particles (ALPs) may be abundantly produced in core-collapse (CC) supernovae (SNe); hence, the cumulative signal from all past supernova (SN) events can create a diffuse flux peaked at energies of about 25 MeV. We improve upon the modeling of the ALPs flux by including a set of CC SN models with different progenitor masses, as well as the effects of failed CC SNe, which yield the formation of black holes instead of explosions. Relying on the coupling strength of ALPs to photons and the related Primakoff process, the diffuse SN ALP flux is converted into gamma rays while traversing the magnetic field of the Milky Way. The spatial morphology of this signal is expected to follow the shape of the Galactic magnetic field lines. We make use of this via a template-based analysis that utilizes 12 years of Fermi-LAT data in the energy range from 50 MeV to 500 GeV. In our benchmark case of the realization of astrophysical and cosmological parameters, we find an upper limit of gaγ≲3.76×10−11 GeV−1 at a 95% confidence level for ma≪10−11 eV, while we find that systematic deviations from this benchmark scenario induce an uncertainty as large as about a factor of two. Our result slightly improves the CAST bound, while still being a factor of six (baseline scenario) weaker than the SN1987A gamma-ray burst limit.
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| 2. |
- Calore, Francesca, et al.
(author)
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511 keV line constraints on feebly interacting particles from supernovae
- 2022
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In: Physical Review D. - 2470-0010 .- 2470-0029. ; 105:6
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Journal article (peer-reviewed)abstract
- Feebly interacting particles with masses with O(10-100) MeV can be copiously produced by core-collapse supernovae (SNe). In this paper we consider the case of MeV-ish sterile neutrinos and dark photons mixed with ordinary neutrinos and photons, respectively. Furthermore, both sterile neutrinos and dark photons may decay into positrons on their route to Earth. Such positrons would annihilate with electrons in the Galactic medium and contribute to the photon flux in the 511 keV line. Using the spectrometer on INTEGRAL observation of this line improves the bounds on the mixing parameters for these particles by several orders of magnitude below what is already excluded by the SN 1987A energy-loss argument.
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| 3. |
- Calore, Francesca, et al.
(author)
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Uncovering axionlike particles in supernova gamma-ray spectra
- 2024
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In: Physical Review D. - 2470-0010 .- 2470-0029. ; 109:4
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Journal article (peer-reviewed)abstract
- A future Galactic supernova (SN) explosion can lead to a gamma-ray signal induced by ultralight axionlike particles (ALPs) thermally produced in the SN core and converted into high-energy photons in the Galactic magnetic field. The detection of such a signal is in the reach of the Large Area Telescope aboard the Fermi Gamma-Ray Space Telescope. The observation of gamma-ray emission from a future SN has a sensitivity to gaγ≳4×10−13 GeV−1 for a SN at fiducial distance of 10 kpc and would allow us to reconstruct the ALP-photon coupling within a factor of ∼2, mainly due to the uncertainties on the modeling of the Galactic magnetic field.
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| 4. |
- Carenza, Pierluca, 1995-, et al.
(author)
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Cross section for supernova axion observation in neutrino water Čherenkov detectors
- 2024
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In: Physical Review C. - 2469-9985 .- 2469-9993. ; 109:1
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Journal article (peer-reviewed)abstract
- Axions coupled to nucleons might be copiously emitted from core-collapse supernovae (SNe). If the axion-nucleon coupling is strong enough, then axions would be emitted from the SN as a burst and, reaching Earth, may excite the oxygen nuclei in water Čherenkov detectors (16O+a→16O∗). This process will be followed by decay(s) of the excited state resulting in an emission of photons and thus providing a possibility for a direct detection of axions from a galactic SN in large underground neutrino Čherenkov detectors. Motivated by this possibility, we present an updated calculation of axion-oxygen cross section obtained by using self-consistent continuum random-phase approximation. We calculate the branching ratio of the oxygen nucleus deexcitation into γ rays, neutrons, protons, and α particles and also consider photon emission from secondary nuclei to compute a total γ spectrum created when axions excite 16O. These results are used to revisit the detectability of axions from SN 1987A in Kamiokande-II.
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| 5. |
- Lella, Alessandro, et al.
(author)
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Getting the most on supernova axions
- 2024
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In: Physical Review D. - 2470-0010 .- 2470-0029. ; 109:2
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Journal article (peer-reviewed)abstract
- Axionlike particles (ALPs) coupled to nucleons might be copiously emitted from a supernova (SN) core. We extend existing bounds on free-streaming ALPs to the case in which these are so strongly interacting with the nuclear matter to be trapped in the SN core. For strongly interacting ALPs, we also extend the bound from the absence of an ALP-induced signal in Kamiokande-II neutrino detector at the time of SN 1987A. We find that combining the different arguments, SNe exclude values of ALP-nucleon coupling gaN≳10−9 for ALP masses ma≲1 MeV. Remarkably, in the case of canonical QCD axion models, the SN bounds exclude all values of ma≳10−2 eV. This result prevents the possibility for current and future cosmological surveys to detect any signatures due to hot dark matter QCD axion mass.
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| 6. |
- Lella, Alessandro, et al.
(author)
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Protoneutron stars as cosmic factories for massive axionlike particles
- 2023
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In: Physical Review D. - 2470-0010 .- 2470-0029. ; 107:10
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Journal article (peer-reviewed)abstract
- The parameter space of massive axionlike particles (ALPs) with ma similar to O(100) MeV and coupled with nucleons is largely unexplored. Here, we present new constraints in this parameter region. In doing so, we characterize the supernova emissivity of heavy ALPs from a protoneutron star, including for the first time mass effects in both nucleon-nucleon Bremsstrahlung and pionic Compton processes. In addition, we highlight novel possibilities to probe the couplings with photons and leptons from supernova ALP decays.
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| 7. |
- Lucente, Giuseppe, et al.
(author)
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Axion signatures from supernova explosions through the nucleon electric-dipole portal
- 2022
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In: Physical Review D. - 2470-0010 .- 2470-0029. ; 105:12
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Journal article (peer-reviewed)abstract
- We consider axions coupled to nucleons and photons only through the nucleon electric-dipole moment (EDM) portal. This coupling is a model-independent feature of QCD axions, which solve the strong CP problem, and might arise as well in more general axionlike particle setups. We revise the supernova (SN) axion emission induced by the nucleon EDM coupling and refine accordingly the SN 1987A bound. Furthermore, we calculate the axion flux from a future Galactic SN and show that it might produce a peculiar and potentially detectable gamma-ray signal in a large underground neutrino detector such as the proposed Hyper-Kamiokande. The possibility to detect such a signal offers a way to search for an oscillating nucleon EDM complementary to CASPERe, without relying on the assumption that axions are a sizeable component of the dark matter. Furthermore, if axions from SN produce an observable signal, they could also lead to an amount of cosmological extra radiation observable in future cosmic surveys.
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| 8. |
- Lucente, Giuseppe, et al.
(author)
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Constraining Heavy Axionlike Particles by Energy Deposition in Globular Cluster Stars
- 2022
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 129:1
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Journal article (peer-reviewed)abstract
- Heavy axionlike particles (ALPs) with masses up to a few 100 keV and coupled with photons can be efficiently produced in stellar plasmas. We present a new “ballistic” recipe that covers both the energy-loss and energy-transfer regimes, and we perform the first dedicated simulation of Globular Cluster stars including the ALP energy transfer. This argument allows us to constrain ALPs with ma≲0.4 MeV and gaγ≃10−5 GeV−1, probing a section of the ALP parameter space informally known as the “cosmological triangle”. This region is particularly interesting since it has been excluded only using standard cosmological arguments that can be evaded in nonstandard scenarios.
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| 9. |
- Xiao, Mengjiao, et al.
(author)
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Betelgeuse constraints on coupling between axionlike particles and electrons
- 2022
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In: Physical Review D. - 2470-0010 .- 2470-0029. ; 106:12
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Journal article (peer-reviewed)abstract
- Axionlike particles (ALPs) can be produced by thermal processes in a stellar interior, escape from the star and, if sufficiently light, be converted into photons in the external Galactic magnetic field. Such a process could produce a detectable hard x-ray excess in the direction of the star. In this scenario, a promising class of targets is the red supergiants, massive stars which are experiencing the late part of their evolution. We report on a search for ALP-induced x-ray emission from Betelgeuse, produced via the combined processes of bremsstrahlung, Compton and Primakoff. Using a 50 ks observation of Betelgeuse by the NuSTAR satellite telescope, we set 95% C.L. upper limits on the ALP-electron (gae) and ALP-photon (gaγ) couplings. For masses ma≤(3.5–5.5)×10−11 eV, we find gaγ×gae<(0.4–2.8)×10−24 GeV−1 (depending on the stellar model and assuming a value of the regular Galactic magnetic field in the direction transverse to Betelgeuse of BT=1.4 μG). This corresponds to gae<(0.4–2.8)×10−12 for gaγ>1.0×10−12 GeV−1. This analysis supercedes by over an order of magnitude the limit on gae×gaγ placed by the CAST solar axion experiment and is among the strongest constraints on these couplings.
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