Search for type-III seesaw heavy leptons in pp collisions at √s = 8 TeV with the ATLAS Detector

A search for the pair production of heavy leptons (N[superscript 0],L[superscript ±]) predicted by the type-III seesaw theory formulated to explain the origin of small neutrino masses is presented. The decay channels N[superscript 0] → W[superscript ±]l[superscript ∓] (ℓ = e,μ,τ) and L[superscript ±...

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Bibliographic Details
Main Author: Taylor, Frank E.
Other Authors: Massachusetts Institute of Technology. Department of Physics
Format: Article
Language:en_US
Published: American Physical Society 2016
Online Access:http://hdl.handle.net/1721.1/101100
https://orcid.org/0000-0002-7586-7253
Description
Summary:A search for the pair production of heavy leptons (N[superscript 0],L[superscript ±]) predicted by the type-III seesaw theory formulated to explain the origin of small neutrino masses is presented. The decay channels N[superscript 0] → W[superscript ±]l[superscript ∓] (ℓ = e,μ,τ) and L[superscript ±] → W[superscript ±]ν (ν = ν[subscript e],ν[subscript μ],ν[subscript τ]) are considered. The analysis is performed using the final state that contains two leptons (electrons or muons), two jets from a hadronically decaying W boson and large missing transverse momentum. The data used in the measurement correspond to an integrated luminosity of 20.3  fb[superscript −1] of pp collisions at √s = 8  TeV collected by the ATLAS detector at the LHC. No evidence of heavy lepton pair production is observed. Heavy leptons with masses below 325–540 GeV are excluded at the 95% confidence level, depending on the theoretical scenario considered.