# Search for type-III Seesaw heavy leptons in $pp$ collisions at $\sqrt{s}= 8$ TeV with the ATLAS Detector

Abstract : A search for the pair-production of heavy leptons ($N^0,L^{\pm}$) predicted by the type-III seesaw theory formulated to explain the origin of small neutrino masses is presented. The decay channels $N^0\rightarrow W^{\pm}l^{\mp}$ ($\ell = e, \mu, \tau$) and $L^{\pm}\rightarrow W^\pm \nu$ ($\nu=\nu_e, \nu_\mu, \nu_\tau$) 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 $20.3\,fb^{-1}$ of $pp$ collisions at $\sqrt{s} = 8$ 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.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-01164188
Contributor : Claudine Bombar <>
Submitted on : Tuesday, June 16, 2015 - 11:58:08 AM
Last modification on : Tuesday, April 20, 2021 - 12:00:14 PM

### Citation

G. Aad, Z. Barnovska, N. Berger, M. Delmastro, L. Di Ciaccio, et al.. Search for type-III Seesaw heavy leptons in $pp$ collisions at $\sqrt{s}= 8$ TeV with the ATLAS Detector. Physical Review D, American Physical Society, 2015, 92, pp.032001. ⟨10.1103/PhysRevD.92.032001⟩. ⟨in2p3-01164188⟩

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