Light Pseudoscalar Bosons, PVLAS and the Double Pulsar J0737-3039

Abstract

Light Pseudoscalar Bosons (LPBs) coupled to two photons are predicted by many realistic extensions of the Standard Model and give rise to birefringence and dichroism in a light beam travelling in an external magnetic field. These effects have recently been detected by the PVLAS collaboration, thereby strongly suggesting the existence of a LPB. We provide an astrophysical cross-check for such a claim. Actually, we show that in the double pulsar J0737-3039 photon-LPB conversion can give rise to a characteristic attenuation pattern of the light beam emitted by one of the pulsars when it goes through the magnetosphere of the companion. The effect under consideration shows up in the γ-ray band and can be detected by the upcoming GLAST mission.

Effects of axion-photon mixing on gamma-ray spectra from magnetized astrophysical sources

“…( 24) implies a modulation for MeV < ∼ E < ∼ 100 GeV, as obtained in Ref. [21,22]. Note that for less coherent fields between the two compact stars, N > 1, the modulation would extend down to lower energies.…”

“…where in the second expressions we have substituted Eq. (22). The condition on g 11 is very similar to the resonance condition Eq.…”

“…Ref. [21,22], considered variable γ−ray light curves from double pulsars as signatures for the PVLAS axion-photon mixing parameters. In this scenario, a surface pulsar magnetic field B ∼ 10 12 G yields B ∼ 10 4 G, N ∼ 1 in the accretion region between the pulsars where the γ−rays are produced, and the Goldreich-Julian plasma density is n e ∼ 10 3 cm −3 .…”