Internal seminar

Several anomalies in the neutrino sector are pointing towards the existence of a new (sterile) neutrino state with a mass around 1 eV. The SoLid experiment is located at the SCK•CEN BR2 research reactor in Belgium and will investigate this possibility. Using the large flux of anti-neutrino generated in the reactor, it will collect a high statistics sample of Inverse Beta Decay (IBD) events. These will be used to study the energy and distance dependence of the neutrino flux, which in turn will be used un-ambiguous support or reject the evidence of sterile neutrinos being the cause of these anomalies. The measurement is challenging as one has to operate a detector very close to the high radiation environment of a nuclear reactor and on the surface with little overburden to shield against cosmic rays. SoLid is employing a new technology using highly segmented scintillators with excellent particle ID to face these challenges. The 1.6-tons detector was installed towards the end of 2017 and is taking data since early 2018. We will describe the detector design, the experimental setup at BR2 and the detection principle. This will be followed by a first look at the data.

Latest results on inclusive top quark pair production cross sections are presented using proton-proton collision data collected by CMS at different centre-of-mass energies, including 5 TeV. Final states with at least one charged lepton and one b-jet are explored to measure inclusive production cross sections. The sensitivity of some these measurements to PDFs and extraction of standard model parameters is also described. Moreover, first ttbar cross sections results in proton-lead collisions are discussed. Differential top quark pair production cross sections are discussed with respect to kinematic variables in final states with at least one lepton. Constraints placed on the EFT operator OtG are discussed as well as the measurement of ttbar asymmetries in the top quark-antiquark system.