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OpenMSIStream provides seamless connection of scientific data stores with streaming infrastructure to allow researchers to leverage the power of decoupled, real-time data streaming architectures. Data streaming is the process of transmitting, ingesting, and processing data continuously rather than in batches. Access to streaming data has revolutionized many industries in the past decade and created entirely new standards of practice and types of analytics. While not yet commonly used in scientific research, data streaming has the potential to become a key technology to drive rapid advances in scientific data collection (e.g., Brookhaven National Lab (2022)). This paucity of streaming infrastructures linking complex scientific systems is due to a lack of tools that facilitate streaming in the diverse and distributed systems common in modern research. OpenMSIStream closes this gap between underlying streaming systems and common scientific infrastructure. Closing this gap empowers novel streaming applications for scientific data including automation of data curation, reduction, and analysis; real-time experiment monitoring and control; and flexible deployment of AI/ML to guide autonomous research. Streaming data generally refers to data continuously generated from multiple sources and passed in small packets (termed messages). Streaming data messages are typically organized in groups called topics and persist for periods of time conducive to processing for multiple uses either sequentially or in small groups. The resulting flows of raw data, metadata, and processing results form “ecosystems” that automate varied data-driven tasks. A strength of data streaming ecosystems is the use of publish-subscribe (“pub/sub”) messaging backbones that decouple data senders (publishers) and recipients (subscribers). Popular message-focused middleware solutions such as RabbitMQ (VMware, 2022), Apache Pulsar (Apache Software Foundation, 2022b), and Apache Kafka (Apache Software Foundation, 2022a) all provide differing capabilities as backbones. OpenMSIStream provides robust and efficient, yet easy, access to the rich data streaming systems of Apache Kafka. 

Abstract Many measurements at the LHC require efficient identification of heavy-flavour jets, i.e. jets originating from bottom (b) or charm (c) quarks. An overview of the algorithms used to identify c jets is described and a novel method to calibrate them is presented. This new method adjusts the entire distributions of the outputs obtained when the algorithms are applied to jets of different flavours. It is based on an iterative approach exploiting three distinct control regions that are enriched with either b jets, c jets, or light-flavour and gluon jets. Results are presented in the form of correction factors evaluated using proton-proton collision data with an integrated luminosity of 41.5 fb -1 at  √s = 13 TeV, collected by the CMS experiment in 2017. The closure of the method is tested by applying the measured correction factors on simulated data sets and checking the agreement between the adjusted simulation and collision data. Furthermore, a validation is performed by testing the method on pseudodata, which emulate various mismodelling conditions. The calibrated results enable the use of the full distributions of heavy-flavour identification algorithm outputs, e.g. as inputs to machine-learning models. Thus, they are expected to increase the sensitivity of future physics analyses.