The LHC experiments have so far calibrated and re-reconstructed data typically years after the end of data-taking to make them usable for precision physics analyses, costing millions of CPU hours. This approach becomes untenable at the HL-LHC, with 10 times larger datasets. Our project implements for the CERN CMS experiment special calibration streams providing jet energy corrections (JEC) with dijet and photon+jet events within 48 hours after data taking. JEC are needed by 90% of physics analyses, and they are the final missing pieces required by precision physics analyses. The implemented streams provide a factor 10—100 increase in the amount of calibration data, enabling a fully automated Prompt calibration which can save tens of person years, millions of CPU hours and speed up the typical CMS analysis cycle times by several years. In addition, it allows to better optimize the trigger menu for physics and better monitoring.

2025

2029