Abstract
The associated production of a single-top with opposite-sign same-flavor (OSSF) dileptons, and (), can lead to striking trilepton and dilepton () events at the LHC, after the top decays. Although these rather generic multilepton signals are flavor-blind, they can be generated by new 4-Fermi flavor changing (FC) scalar, vector and tensor interactions (, ), which we study in this paper; we match the FC 4-Fermi terms to the SMEFT operators and also to different types of FC underlying heavy physics. The main backgrounds to these di- and trilepton signals arise from , and (, ) production, but they can be essentially eliminated with a sufficiently high invariant mass selection on the OSSF dileptons, ; the use of -tagging as an additional selection in the dilepton final state case also proves very useful. We find, for example, that the expected 95% CL bounds on the scale of a tensor(vector) interaction, with the current of LHC data, are or , if analyzed via the dimuon signal or the trilepton one, respectively. The expected reach at the HL-LHC with of data is and for the corresponding and operators. This should be compared to the current bounds of on both the and operators from LEP2 and from followed by . We also study the potential sensitivity at future 27 TeV and 100 TeV high-energy LHC successors, which, for the operators, can reach . We furthermore discuss the possible implications of this class of FC 4-Fermi effective interactions on lepton nonuniversality tests at the LHC.
3 More- Received 30 January 2021
- Accepted 25 March 2021
DOI:https://doi.org/10.1103/PhysRevD.103.075031
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.
Published by the American Physical Society