Periodic Reporting for period 4 - EXPLORINGMATTER (Exploring Matter with Precision Charm and Beauty Production Measurements in Heavy Nuclei Collisions at LHCb) Reporting period: 2019-10-01 to 2021-12-31 Summary of the context and overall objectives of the project EXPLORINGMATTER is a project which uses the experiment LHCb at CERN to study heavy nuclei collisions in a configuration and energy never explored before. These studies can shed light to the Quark Gluon Plasma, a new state of matter still largely unknown.The objectives of the project are listed below.• Objective 1 is to collect data in the three configurations necessary to probe QGP formation and its characteristics: pp, pA and AB collisions, where A and B are the heavy nuclei types. • Objective 2 and 3 are to analyse the data to obtain precise measurements of charmonium, bottomonium and open charm and beauty production in heavy-ions collisions and of cold nuclear matter effects.• Objective 4 is to use the results and techniques from EXPLORINGMATTER to think and design future experiments. Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far The main activities in the first period have been centered around the collection of the data in the pPb, PbPb and SMOG configurations, the last two for the first time ever at LHCb.The data have been collected, stored, reconstructed and analysed by my team, with the help of the experts in the collaboration.The analysis with the PbPb datawere very challenging due to the high multiplicities involved and gave us an important sample of data to develop new techniques to analyse these data and prepare for the future run.The publications obtained using the PbPb data were the first ever at LHCb and an outstanding milestone despite the limited reach in centrality available. The analyses of the fixed-target samples has been another breakthrough of the project, being completely unique in all aspects and addressing an energy not available anywhere else in the world at the moment. The results from these analyses had huge impact in several areas of physics, from particle to nuclear to astrophysics.Finally, the analyses performed with the pPb sample showed a high-level of precision and thanks to ExploringMatter team members LHCb was the first LHC experiment to publish on this sample. In addition, members of ExploringMatter were involved in studies for the upcoming 2022 Run 3 and in future detectors developments meant to strengthen the LHCb participation in the heavy-ion physicsfield. Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far) Through ExploringMatter, PbPb collisions have been collected at LHCb for the first time,and for the first time this region in rapidity has been exploredat this energy with this precision. The study of the several particle production in pPb has been studied for the first time down to zero momentum, crucial milestones for the understanding of cold nuclear matter effects. The results in SMOG collisionsare the first and thus completely unique.This project has no impact on society. drawing-collisions-forb1.png evd-pbar.png