Search for supersymmetry in final states with missing transverse momentum and charm-tagged jets using 139 fb-1 of proton-proton collisions at sqrt(s) = 13 TeV with the ATLAS detector

The paper presents a search for supersymmetric particles (SUSY) produced in proton-proton collisions at sqrt(s)=13 TeV and decaying into final states with missing transverse momentum (ETmiss) and jets originating from charm quarks (c-jets). The data were taken with the ATLAS detector at the LHC from 2015 to 2018, corresponding to an integrated luminosity of 139 fb-1. The signal topology is characterized by the presence of c-jets and large ETmiss from the undetected lightest supersymmetric particle (χ~10). No significant excess of events over the expected Standard Model background expectation is observed in optimized signal regions, and limits are set on the production cross-sections of the supersymmetric particles. The results are interpreted in specific R-parity-conserving SUSY models: Pair production of charm squarks (c~1) or top squarks (t~1), each decaying into a charm quark and the χ~​10, is excluded at 95% confidence level for squarks with masses up to 900 GeV for scenarios where the mass of χ~10 is below 50 GeV. Additionally, the production of leptoquarks with masses up to 900 GeV is excluded for the scenario where up-type leptoquarks (LQ) decay into a charm quark and a neutrino (cν). Model-independent limits on cross-sections and event yields for processes beyond the Standard Model are also reported.