Dark gauge boson production from neutron stars via nucleon-nucleon bremsstrahlung

Understand

We discuss the dark gauge boson emission from neutron stars via nucleon-nucleon bremsstrahlung.

• Through the rigorous treatment of the effective field theory prescription and the thermal effect, we derive the relevant couplings of dark gauge bosons to hadrons in medium.
• As a specific example, the $U(1)_{\rm B-L}$ gauge boson scenario is chosen to investigate dark gauge boson emissivities during supernovae and cooling of young neutron stars.
• From the stellar cooling argument, we obtain the constraints on the $\rm B-L$ gauge coupling for given gauge boson masses in two observations: the duration of the supernova neutrino signal of SN1987A, and the inferred x-ray luminosity of the compact object in the remnant of SN1987A (NS1987A).