Aad G.Abbott B.Abbott D. C.Abeling K.Abidi S. H.Aboulhorma A.Abramowicz H.Abreu H.Abulaiti Y.Abusleme Hoffman A. C.Acharya B. S.Achkar B.Adam L.Adam Bourdarios C.Adamczyk L.Adamek L.Addepalli S. V.Adelman J.Adiguzel A.Adorni S.Adye T.Affolder A. A.Afik Y.Agaras M. N.Agarwala J.Aggarwal A.Agheorghiesei C.Aguilar-Saavedra J. A.Ahmad A.Ahmadov F.Ahmed W. S.Ai X.Aielli G.Aizenberg I.Akbiyik M.Akesson T. P. A.Akimov A. V.Al Khoury K.Alberghi G. L.Albert J.2025-05-192025-05-192023/07/121029-8479http://dx.doi.org/10.1007/JHEP07(2023)090https://publicacionesabiertas.userena.cl/handle/123456789/244This paper presents a search for a new Z' vector gauge boson with the ATLAS experiment at the Large Hadron Collider using pp collision data collected at root s = 13TeV, corresponding to an integrated luminosity of 139 fb(-1). The new gauge boson Z' is predicted by L-mu - L-tau models to address observed phenomena that can not be explained by the Standard Model. The search examines the four-muon (4 mu) final state, using a deep learning neural network classifier to separate the Z' signal from the Standard Model background events. The di-muon invariant masses in the 4 mu events are used to extract the Z' resonance signature. No significant excess of events is observed over the predicted background. Upper limits at a 95% confidence level on the Z' production cross-section times the decay branching fraction of pp -> Z' mu mu -> 4 mu are set from 0.31 to 4.3 fb for the Z' mass ranging from 5 to 81 GeV. The corresponding common coupling strengths, g(Z'), of the Z' boson to the second and third generation leptons above 0.003 - 0.2 have been excluded.L-TAU, L-MU, DISTRIBUTIONS, PHYSICSArticle