Conveners
Axions & ALPs I
- Bhupal Dev (Washington University in St. Louis)
Axions are a generic expectation in many extensions of the Standard Model. Astrophysical objects have long been used to search for axions through, for example, cooling of white dwarfs or neutron stars. In these objects, axions can be created through scattering processes in the core and escape the star. However, the emitted axions can then be detected in X-ray observations if they convert into...
Axion-like-particles (ALPs) emitted from the core of magnetars can convert to photons in their magnetospheres. We study such emissions in the soft-gamma-ray range (300 keV to 1 MeV), where the ALP spectrum peaks and astrophysical backgrounds from resonant Compton upscattering are expected to be suppressed. Using published quiescent soft-gamma-ray flux upper limits (ULs) in 6 Magnetars...
Recent years there are more and more observed fast radio bursts (FRBs)
Their origin is still unknown. We propose a new origin of FRBs from the
well-motivated axion.
Axions may be produced in nuclear matter via neutron bremsstrahlung. We calculate the mean free path of axions in neutron star merger conditions, and find that axions created in a merger would free-stream through it, leading to cooling of the merger. We calculate the emissivity of axions over a wide range of temperatures, densities, and axion-neutron coupling constants, and translate that into...
Searches for pseudoscalar axion-like-particles (ALPs) typically rely on their decay in beam dumps or their conversion into photons in haloscopes and helioscopes. We point out a new experimental direction for ALP probes through their production via the Primakoff process or Compton-like scattering off of electrons or nuclei. We consider ALPs produced by the intense gamma ray flux available from...
