Search for a Heavy Composite Majorana Neutrino in Events with Dilepton Signatures from Proton-Proton Collisions at √s = 13 TeV

Physics Letters B 2023
Kārlis Dreimanis, Guntis Pikurs, Markus Seidel, Viesturs Veckalns, CMS Collaboration

Results are presented of a search for a heavy Majorana neutrino Image 1 decaying into two same-flavor leptons ℓ (electrons or muons) and a quark-pair jet. A model is considered in which the Image 1 is an excited neutrino in a compositeness scenario. The analysis is performed using a sample of proton-proton collisions at s=13TeV recorded by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 138fb−1. The data are found to be in agreement with the standard model prediction. For the process in which the Image 1 is produced in association with a lepton, followed by the decay of the Image 1 to a same-flavor lepton and a quark pair, an upper limit at 95% confidence level on the product of the cross section and branching fraction is obtained as a function of the Image 1 mass Image 2 and the compositeness scale Λ. For this model the data exclude the existence of Image 3 (Image 4) for Image 2 below 6.0 (6.1) TeV, at the limit where Image 2 is equal to Λ. For Image 5, values of Λ less than 20 (23) TeV are excluded. These results represent a considerable improvement in sensitivity, covering a larger parameter space than previous searches in Image 6 collisions at 13 TeV.

Keywords
CMS LHC Composite fermions Heavy leptons
DOI
10.1016/j.physletb.2023.137803
Hyperlink
https://www.sciencedirect.com/science/article/pii/S0370269323001375?via%3Dihub

The CMS Collaboration, A.Tumasyan, K.Dreimanis, G.Pikurs, M.Seidel, V.Veckalns ... [et al.]. Search for a Heavy Composite Majorana Neutrino in Events with Dilepton Signatures from Proton-Proton Collisions at √s = 13 TeV. Physics Letters B, 2023, Vol. 843, Article number 137803. ISSN 0370-2693. Available from: doi:10.1016/j.physletb.2023.137803

Publication language
English (en)