Recording and reconstructing 10 billion unbiased b hadron decays in CMS

The CMS experiment has recorded a sample of 10 billion events containing the unbiased decays of b hadrons. The accumulation, processing, and validation of this data set were delivered without significant impact on the core physics programme of CMS. Events were recorded with peak trigger rates in excess of 50 and 5 kHz at L1 and HLT, respectively, and written (parked) to tape at an average rate of 2 GB/s. New algorithms have been developed to reconstruct and identify electrons with high efficiency at transverse momenta as low as 0.5 GeV. These algorithms were validated using a pilot reconstruction campaign. The entire data set has now been reconstructed.