Abstract
A search for new physics in proton-proton collisions having final states with an electron or muon and missing transverse energy is presented. The analysis uses data collected in 2012 with the CMS detector, at an LHC center-of-mass energy of 8 TeV, and corresponding to an integrated luminosity of 19.7 inverse femtobarns. No significant deviation of the transverse mass distribution of the charged lepton-neutrino system from the standard model prediction is found. Mass exclusion limits of up to 3.28 TeV at a 95% confidence level for a W' boson with the same couplings as that of the standard model W boson are determined. Results are also derived in the framework of split universal extra dimensions, and exclusion limits on Kaluza-Klein W[KK,2] states are found. The final state with large missing transverse energy also enables a search for dark matter production with a recoiling W boson, with limits set on the mass and the production cross section of potential candidates. Finally, limits are established for a model including interference between a left-handed W' boson and the standard model W boson, and for a compositeness model.
Highlights
The standard model (SM) of particle physics is a theory of the structure of matter, describing the properties of all known elementary particles and the forces between them
Despite the great success of the SM, beyond the SM (BSM) physics addresses a variety of open issues
To name a few examples, the relationship of the electroweak and gravitational energy scales must be understood and incorporated in the theory, an underlying concept is needed to explain the origin of the observed three fermion families, and astrophysical observations indicate the presence of dark matter (DM) not described in the standard model
Summary
The standard model (SM) of particle physics is a theory of the structure of matter, describing the properties of all known elementary particles and the forces between them. The search presented in this paper is sensitive to deviations from the SM prediction for the transverse mass spectrum of events with a charged lepton (electron or muon) and one or more particles that cannot be directly detected (neutrino, dark matter particle) in the final state. Since the discovery of the W-boson, experiments have scrutinized the lepton and missing transverse energy channel for evidence of physics beyond the standard model. The shape of the distribution is taken into account by using a binned likelihood method This approach is especially important as the examined theories predict very different signal event distributions.
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