Speaker
Description
In Run 3 using a combination of beta* and crossing angle settings, the instantaneous luminosity delivered to the high-intensity interaction points IP1 and IP5 of LHC will be leveled to a maximum of 2e34 cm-2s-1 in collisions, from a few hours (in 2022) up more than 10 hours (in 2023/2024). This leveled value is set by the cryo-cooling capacity of the existing inner triplet and, slightly in the shadow, by the experiments to match their capacity to absorb the interaction data in their trigger and DAQ systems. While this goal applies to the instantaneous beam luminosity considering all bunches, bunch-to-bunch variations may change the picture, require further adjustments, and may impose constraints to the leveled goal. In this presentation we will go through the key results from Run 2 data on bunch-to-bunch luminosity variations in collisions. We would explain their origins, the observations during collisions in the Run 2 fills, along with expectations for Run 3 conditions. We will also try to propose strategy to balance the conflicting requirement of a maximum average (beam) luminosity leveling with that from bunch-to-bunch variations for an overall optimal exploitation of the leveling time and integrated luminosity. The situation of LHCb will also be analysed.
