CMS Collaboration2024-05-082024-05-082023CMS Collaboration. (2023). Search for a heavy composite Majorana neutrino in events with dilepton signatures from proton-proton collisions at s=13 TeV<math><msqrt is="true"><mrow is="true"><mi is="true">s</mi></mrow></msqrt><mo linebreak="goodbreak" linebreakstyle="after" is="true">=</mo><mn is="true">13</mn><mtext is="true"> TeV</mtext></math>. Physics Letters B, 843, 137803. https://doi.org/10.1016/j.physletb.2023.137803https://hdl.handle.net/1911/115646Results 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.engExcept where otherwise noted, this work is licensed under a Creative Commons Attribution (CC BY) license. Permission to reuse, publish, or reproduce the work beyond the terms of the license or beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.Journal article1-s20-S0370269323001375-mainhttps://doi.org/10.1016/j.physletb.2023.137803