Speaker
Alessandro Morandini
(RWTH Aachen University)
Description
Ultra-relativistic particles can be produced by the decay of weak-scale LLPs and act as dark radiation. The cosmologically interesting range $\Delta N_\text{eff} \sim 0.01–0.1$ corresponds to LLP decay lengths at the mm scale. These decay lengths lie at the boundary between prompt and displaced signatures at the LHC. We consider a scenario where the LLP decays into a lepton and a (nearly) massless invisible particle. By reinterpreting searches for promptly decaying sleptons and for displaced leptons we can then compare LHC exclusions with cosmological observables. We find that the CMB-S4 target value is already excluded by current LHC searches.
Authors
Dr
Elias Bernreuther
(Fermi National Accelerator Laboratory)
Prof.
Felix Kahlhoefer
(KIT)
Dr
Michele Lucente
(RWTH)
Alessandro Morandini
(RWTH Aachen University)
