Red-giant branch stellar cores as macroscopic dark matter detectors

We show that macroscopic dark matter (DM) impacts on the degenerate helium cores of red-giant branch (RGB) stars can ignite fusion via DM-baryon elastic scattering. The onset burning leads to a characteristic drop in luminosity and rise temperature marks transition horizontal star. such alter RGB function globular clusters (GCs), focusing particular GC M15. Using models M15 constructed with stellar simulation code MESA, we compute expected DM-ignition event rates theoretical functions under null signal hypotheses. constrain DM masses ${10}^{17}\text{ }\text{ }\mathrm{g}\ensuremath{\lesssim}{m}_{\ensuremath{\chi}}\ensuremath{\lesssim}{10}^{20}\text{ }\mathrm{g}$ geometric cross sections ${10}^{2}\text{ }{\mathrm{cm}}^{2}\ensuremath{\lesssim}{\ensuremath{\sigma}}_{\ensuremath{\chi}n}\ensuremath{\lesssim}{10}^{7}\text{ }{\mathrm{cm}}^{2}$ assuming is sourced by background Milky Way halo. also place more stringent constraints formed subhalo survives today.