Redefinition of the RAW data format in pp collisions for CMS Run 3.

Redefining the RAW data format using semi-processed information to reduce the event size to disk. A notable example will be the Run 3 Heavy Ion runs. The tracker digits will be dropped from the RAW event and replaced with a new tracker data format. At HLT the tracker clusters are produced, the barycenter is calculated and only this value is stored in the new RAW data format instead of the list of the silicon strip amplitudes. Preliminary studies show a size reduction of $20\mbox{--}25%$ of the whole data with respect to the traditional RAW storage scheme. Dedicated studies on physics performances, in particular tracking ones, have been performed using 2018 data and $t\bar{t}$ Monte Carlo samples. Such an approach, or similar ones, could be beneficial also for very busy proton-proton events, characterised by a high pile-up level, such as the one in the HL-LHC era.