Erratum: Dark Matter from Exponential Growth [Phys. Rev. Lett. 127, 191802 (2021)].

This corrects the article DOI: 10.1103/PhysRevLett.127.

Dark Matter from Exponential Growth.

We propose a novel mechanism for the production of dark matter (DM) from a thermal bath based on the idea that DM particles χ can transform heat bath particles ψ: χψ→χχ. For a small initial abundance of χ, this leads to an exponential growth of the DM number density in close analogy to other familiar exponential growth processes in nature. We demonstrate that this mechanism complements freeze-in and freeze-out production in a generic way, opening new parameter space to explain the observed DM abundance, and we discuss observational prospects for such scenarios.

Strong Constraints on Self-Interacting Dark Matter with Light Mediators.

Coupling dark matter to light new particles is an attractive way to combine thermal production with strong velocity-dependent self-interactions. Here we point out that in such models the dark matter annihilation rate is generically enhanced by the Sommerfeld effect, and we derive the resulting constraints from the cosmic microwave background and other indirect detection probes. For the frequently studied case of s-wave annihilation, these constraints exclude the entire parameter space where the self-interactions are large enough to address the small-scale problems of structure formation.

A facility to search for hidden particles at the CERN SPS: the SHiP physics case.

This paper describes the physics case for a new fixed target facility at CERN SPS. The SHiP (search for hidden particles) experiment is intended to hunt for new physics in the largely unexplored domain of very weakly interacting particles with masses below the Fermi scale, inaccessible to the LHC experiments, and to study tau neutrino physics. The same proton beam setup can be used later to look for decays of tau-leptons with lepton flavour number non-conservation, [Formula: see text] and to search for weakly-interacting sub-GeV dark matter candidates.

Large hierarchies from approximate R symmetries.

We show that hierarchically small vacuum expectation values of the superpotential in supersymmetric theories can be a consequence of an approximate R symmetry. We briefly discuss the role of such small constants in moduli stabilization and understanding the huge hierarchy between the Planck and electroweak scales.