This is May’s edition of the newsletter of the COST action. The aim is to keep you updated on recent and upcoming conferences and postdoc positions on subjects related to WISPs.
Cosmic Wispers preprints
Natural coordinates and horizontal approximations in two-field cosmological models,
C. I. Lazaroiu
https://arxiv.org/abs/2305.12547
We construct natural local coordinate systems on the phase space of two-field cosmological models with orientable target space, which allow for a description of cosmological flows through quantities of direct physical interest. Such coordinates are induced by the fundamental observables of the model, which we formulate geometrically using the tautological bundle of the tangent bundle of the scalar manifold. We also describe a large class of geometric dynamical approximations induced by the choice of an Ehresmann connection in the tangent bundle of the scalar manifold. Such approximations take a conceptually simple form in natural coordinates and we illustrate one of them as an application.
https://arxiv.org/abs/2301.00217v2
We discuss the behavior of cosmological curves and their first order infrared approximants near critical ends of the scalar manifold Σ and near interior critical points of the scalar potential for tame hyperbolizable two-field cosmological models by determining the universal forms of the asymptotic gradient flow of the classical effective potential with respect to the uniformizing metric near all these points and ends. We compare the asymptotic behavior of gradient flow curves with numerical results for cosmological curves.
https://arxiv.org/abs/2405.09578
Dark Matter (DM) can become captured, deposit annihilation energy, and hence increase the heat flow in exoplanets and brown dwarfs. Detecting such a DM-induced heating in a population of exoplanets in the inner kpc of the Milky Way thus provides potential sensitivity to the galactic DM halo parameters. We develop a Bayesian Hierarchical Model to investigate the feasibility of DM discovery with exoplanets and examine future prospects to recover the spatial distribution of DM in the Milky Way.
https://arxiv.org/abs/2405.00153
In this paper, we explore the phenomenology of massive Axion-Like Particles (ALPs) coupled to quarks and gluons, dubbed 'QCD ALPs', with an emphasis on the associated low-energy observables. ALPs coupled to gluons and quarks not only induce nuclear interactions at scales below the QCD-scale, relevant for ALP production in supernovae (SNe), but naturally also couple to photons similarly to the QCD-axion. We discuss the link between the high-energy formulation of ALP theories and their effective couplings with nucleons and photons. The induced photon coupling allows ALPs with masses larger than 1 MeV to efficiently decay into photons, and astrophysical observables severely constrain the ALP parameter space. We show that a combination of arguments related to SN events rule out ALP-nucleon couplings down to g~1010-1011 a region of the parameter space that was hitherto unconstrained.
https://arxiv.org/abs/2405.02395
Axion-like particles (ALPs) coupled to nucleons can be efficiently produced in the interior of protoneutron stars (PNS) during supernova (SN) explosions. If these ALPs are also coupled to photons they can convert into gamma rays in the Galactic magnetic field. This SN-induced gamma-ray burst can be observable by gamma-ray telescopes like Fermi-LAT if the SN is in the field of view of the detector. We show that the observable gamma-ray spectrum is sensitive to the production processes in the SN core. In particular, if the nucleon-nucleon bremsstrahlung is the dominant axion production channel, one expects a thermal spectrum with average energy E≃50 MeV. In this case the gamma-ray spectrum observation allows for the reconstruction of the PNS temperature. In case of a sizable pion abundance in the SN core, one expects a second spectral component peaked at E≃200 MeV due to axion pionic processes. We demonstrate that, through a dedicated LAT analysis, we can detect the presence of this pionic contribution, showing that the detection of the spectral shape of the gamma-ray signal represents a unique probe of the pion abundance in the PNS.
We encourage participants in the COST action to send us a small summary, typically smaller than the abstract, of their own articles that will appear in the arXiv (after they appear, with their arXiv numbers). The summary will be disseminated in the newsletter.
Send email to
Alessandro Lella alessandro.lella@ba.infn.it
Damiano Fiorillo damiano.fiorillo@nbi.ku.dk
with subject:
preprint summary for Cosmic Wispers newsletter
PhD/Postdoc/Junior Positions
Conferences
International conference on Neutrinos and Dark Matter (NuDM-2024) link