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.
Primary authors
Dr
Elias Bernreuther
(Fermi National Accelerator Laboratory)
Prof.
Felix Kahlhoefer
(KIT)
Dr
Michele Lucente
(RWTH)
Alessandro Morandini
(RWTH Aachen University)
