Abstract
A search is presented for new particles produced at the LHC in proton-proton collisions at sqrt{s} = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb−1, collected in 2017–2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb−1, collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.
Highlights
The standard model (SM) of particle physics has been widely recognized as a very successful, yet incomplete theory
Templates for genuine photons are obtained from simulation, while templates for misreconstructed jets are taken from a control regions (CRs) in data with an inverted photon isolation requirement that is enriched in quantum chromodynamics (QCD) multijet events
The result is interpreted in terms of exclusion limits at 95% confidence level on the parameters of a number of models of beyond-the-SM physics
Summary
The standard model (SM) of particle physics has been widely recognized as a very successful, yet incomplete theory. The existence of additional spatial dimensions beyond the known three could explain the large difference in strength between the gravitational and electroweak (EW) interactions In this scenario, gravitons can be produced in proton-proton (pp) collisions via their enhanced couplings to quarks or gluons and avoid detection by escaping in the additional dimensions. Representative Feynman diagrams for a subset of these signal models are shown in the first three panels of figure 1 In these models the final-state particles are not detectable, but one needs a visible detector signature to be able to identify and record such events. The chosen experimental signature can be used to probe other BSM scenarios with new particles decaying into final states with visible and invisible particles One such scenario probed by the present search is the production of leptoquarks (LQs). Information related to the validation of this implementation is provided as supplementary material
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.