Light dark matter scattering in outer neutron star crusts

We calculate for the first time the phonon excitation rate in the outer crust of a neutron star due to scattering from light dark matter (LDM) particles gravitationally boosted into the star. We consider dark matter particles in the sub-GeV mass range scattering off a periodic array of nuclei through an effective scalar-vector interaction with nucleons. We find that LDM effects cause a modification of the net number of phonons in the lattice as compared to the standard thermal result. In addition, we estimate the contribution of LDM to the ion-ion thermal conductivity in the outer crust and find that it can be significantly enhanced at large densities. Our results imply that for magnetized neutron stars the LDM-enhanced global conductivity in the outer crust will tend to reduce the anisotropic heat conduction between perpendicular and parallel directions to the magnetic field.Comment: 14 pages, 3 figure

Diffusion of dark matter in a hot and dense nuclear environment

We calculate the mean free path in a hot and dense nuclear environment for a fermionic dark matter particle candidate in the $\sim$GeV mass range interacting with nucleons via scalar and vector effective couplings. We focus on the effects of density and temperature in the nuclear medium in order to evaluate the importance of the final state blocking in the scattering process. We discuss qualitatively possible implications for opacities in stellar nuclear scenarios, where dark matter may be gravitationally accreted.Comment: 17 pages, 7 figure

René Edmont Malaise (1892-1978), un personaje famoso por su trampa

René Malaise was an Entomologist of the twentieth century who devoted much of his life to the study of Symphyta, a group of Hymenoptera which focused his PhD. However, the contribution for which he is known among the Entomologists, is the invention of a trap to collect flying insects, known as Malaise trap. This invention is at present widely used in entomological studies conducted throughout the world