Jul 6 – 13, 2022
Bologna, Italy
Europe/Rome timezone

Exploring dark sector parameters in light of neutron star temperatures

Jul 8, 2022, 9:15 AM
Room 8 (Blu)

Room 8 (Blu)

Parallel Talk Astroparticle Physics and Cosmology Astroparticle Physics and Cosmology


Prof. Guey-Lin Lin (Institute of Physics, National Yang Ming Chiao Tung University, Taiwan)


Neutron star (NS) as the dark matter (DM) probe has gained a broad
attention recently, either from heating due to DM annihilation or
its stability under the presence of DM. In this work, we investigate
spin-$1/2$ fermionic DM $\chi$ charged under the $U(1)_{X}$
in the dark sector. The massive gauge boson $V$ of
$U(1)_{X}$ gauge group can be produced in NS via DM annihilation. The produced gauge boson can decay
into Standard Model (SM) particles before it exits NS, despite its
tiny couplings to SM particles. Thus, we perform a systematic study on $\chi\bar{\chi}\to2V\to4{\rm SM}$
as a new heating mechanism for NS in addition to $\chi\bar{\chi}\to2{\rm SM}$
and kinetic heating from DM-baryon scattering. The self-trapping due
to $\chi V$ scattering is also considered.
We assume the general framework that both kinetic and mass mixing terms between $V$ and SM gauge bosons are present. This allows both vector and axial-vector couplings between $V$ and SM fermions even for $m_V\ll m_Z$.
Notably, the contribution from axial-vector coupling is not negligible
when particles scatter relativistically.
We point out that the above approaches to DM-induced NS heating are not yet adopted
in recent analyses. Detectabilities of the aforementioned
effects to the NS surface temperature by the future telescopes are
discussed as well.

In-person participation Yes

Primary authors

Prof. Guey-Lin Lin (Institute of Physics, National Yang Ming Chiao Tung University, Taiwan) Dr Yen-Hsun Lin (Physics Division, National Center for Theoretical Sciences, Taipei 106, Taiwan and Institute of Physics, Academia Sinica, Taipei 11529, Taiwan)

Presentation materials