Search

Abstract Cosmology may give rise to appreciable populations of both particle dark matter and primordial black holes (PBH) with the combined mass density providing the observationally inferred value ΩDM ≈ 0.26. Early studies highlighted that scenarios with both particle dark matter and PBH are strongly excluded by γ-ray limits for particle dark matter with a velocity independent thermal cross section 〈σν〉 ~ 3 × 10−26cm3/s, as is the case for classic WIMP dark matter. Here we examine the limits from di use γ-rays on velocity-dependent, including annihilations which are p-wave with 〈σν〉 ∝ v 2 or d-wave 〈σν〉 ∝ v 4, which we find to be considerably less constraining. This work also utilizes a refined treatment of the PBH dark matter density profile. Importantly, we highlight that even if the freeze-out process is p-wave it is typical for (loop/phase-space) suppressed s-wave processes to actually provide the leading contributions to the experimentally constrained γ-ray flux from the PBH halo.

Abstract In light of the recent LHCb observation of CP violation in the charm sector, we review standard model (SM) predictions in the charm sector and in particular for ΔA CP. We get as an upper bound in the SM |ΔA CP SM | ≤ 3.6 × 10−4, which can be compared to the measurement of ΔA CP LHCb2019 = (−15.4 ± 2.9) × 10−4. We discuss resolving this tension within an extension of the SM that includes a flavour violating Z′ that couples only to s ¯ s $$ \overline{s}s $$ and c ¯ u $$ \overline{c}u $$ . We show that for masses below 80 GeV and flavour violating coupling of the order of 10−4, this model can successfully resolve the tension and avoid constraints from dijet searches, D 0 − D ¯ 0 $$ {\overline{D}}^0 $$ mixing and measurements of the Z width.