Pile up management at the High Luminosity LHC and introduction to the crab-kissing concept

Upgrading the integrated performance of the LHC, while preserving the quality of the physics data delivered to the experiments, is a real challenge for the High-Luminosity LHC (HL-LHC). This paper will give an overview of the situation in terms of performance and so-called pile up density which directly impacts onto the reconstruction efficiency of the primary vertices at the interaction point. Both the present HL-LHC baseline and its possible extension with the so-called crab-kissing scheme will be presented in this context.