Trigger-less readout and unbiased data quality monitoring of the CMS drift tubes muon detector

The CMS experiment 40MHz data scouting project is aimed at intercepting the data produced at the level of the detectors' front-end without the filters induced by hardware-based triggers. A first implementation is realized by the trigger-less reading and processing of a fraction of the Drift Tube (DT) muon detector, equipped with a preliminary version of the Phase-2 Upgrade on-detector electronics boards. The data are transferred via high-speed optical links to back-end boards independently from the central experiment data acquisition (DAQ). This permits real-time monitoring of detector status, based on all signals produced at the front-end level, and provides an unbiased estimate of the CMS DT hit-rate under various data-taking conditions.