Dynamic Aperture Performance for Different Collision Optics Scenarios for the LHC Luminosity Upgrade

The ATS [1] optics solution for the HL-LHC offers the possibility of different collision optics, with a β∗ as small as 10 cm in both transverse planes, or with a β∗ aspect ratio of up to 4 pushing β∗ to even smaller value (5 cm) in the parallel separation plane while relaxing it (20 cm) in the crossing plane. The latter configuration features two possible options for alternative orientations of the crossing plane in the two high luminosity insertions, both considered in this study. In this paper we study the impact of a few selected field imperfection models of the new magnets foreseen for the upgrade through tracking simulations and scaling laws.