Production of vector resonances at the LHC via WZ-scattering: a unitarized EChL analysis

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In the present work we study the production of vector resonances at the LHC by means of the vector boson scattering W Z → W Z and explore the sensitivities to these resonances for the expected future LHC luminosities. We are assuming that these vector resonances are generated dynamically from the self interactions of the longitudinal gauge bosons, W_(L) and Z_(L), and work under the framework of the electroweak chiral Lagrangian to describe in a model independent way the supposedly strong dynamics of these modes. The properties of the vector resonances, mass, width and couplings to the W and Z gauge bosons are derived from the inverse amplitude method approach. We implement all these features into a single model, the IAM-MC, adapted for MonteCarlo, built in a Lagrangian language in terms of the electroweak chiral Lagrangian and a chiral Lagrangian for the vector resonances, which mimics the resonant behavior of the IAM and provides unitary amplitudes. The model has been implemented in MadGraph, allowing us to perform a realistic study of the signal versus background events at the LHC. In particular, we have focused our study on the pp → W Zjj type of events, discussing first on the potential of the hadronic and semileptonic channels of the final W Z, and next exploring in more detail the most clear signals. These are provided by the leptonic decays of the gauge bosons, leading to a final state with ℓ^(+)_(1)ℓ^(−)_(1)ℓ^(+)_(2)νjj, ℓ = e, µ, having a very distinctive signature, and showing clearly the emergence of the resonances with masses in the range of 1.5–2.5 TeV, which we have explored.
Open Access, © The Authors. We thank P. Arnan for providing us with the FORTRAN code to localize the IAM resonances and for his help at the early stages of this work. A.D. thanks F.J. Llanes Estrada for previous collaboration. This work is supported by the European Union through the ITN ELUSIVES H2020-MSCA-ITN-2015//674896 and the RISE INVISIBLESPLUS H2020-MSCA-RISE-2015//690575, by the Spanish MINECO through the projects FPA2013-46570-C2-1-P, FPA2014-53375-C2-1-P, FPA2016-75654-C2-1-P, FPA2016-76005- C2-1-P, FPA2016-78645-P (MINECO/ FEDER, EU), by the Spanish Consolider-Ingenio 2010 Programme CPAN (CSD2007-00042) and by the Spanish MINECO’s “Centro de Excelencia Severo Ochoa” Programme under grants SEV-2012-0249 and SEV-2016-0597–36–JHEP11(2017)098 and the “María de Maeztu” Programme under grant MDM-2014-0369. X.M. is supported through the Spanish MINECO “Ramón y Cajal” Programme (RYC-2015-17173). R.L.D is supported by the Spanish MINECO grant MINECO:BES-2012-056054, the MINECO project FIS2013-41716-P and the “Ramón Areces” Foundation. We also acknowledge 8000 hours of computer time granted at a small departamental cluster at the UCM.
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