This letter presents a search for narrow, high-mass resonances in the 𝑍𝛾 final state with the 𝑍 boson decaying into a pair of electrons or muons. The √𝑠=13TeV 𝑝𝑝 collision data were recorded by the ATLAS detector at the CERN Large Hadron Collider and have an integrated luminosity of 140 fb−1. The data are found to be in agreement with the Standard Model background expectation. Upper limits are set on the resonance production cross section times the decay branching ratio into 𝑍𝛾. For spin-0 resonances produced via gluon–gluon fusion, the observed limits at 95% confidence level vary between 65.5 fb and 0.6 fb, while for spin-2 resonances produced via gluon–gluon fusion (or quark–antiquark initial states) limits vary between 77.4 (76.1) fb and 0.6 (0.5) fb, for the mass range from 220 GeV to 3400 GeV.

Aad, G., Abbott, B., Abeling, K., Abicht, N.J., Abidi, S.H., Aboulhorma, A., et al. (2024). Search for the Zγ decay mode of new high-mass resonances in pp collisions at s=13 TeV with the ATLAS detector. PHYSICS LETTERS. SECTION B, 848, 138394-1-138394-23 [10.1016/j.physletb.2023.138394].

Search for the Zγ decay mode of new high-mass resonances in pp collisions at s=13 TeV with the ATLAS detector

Alberghi, G. L.;Alfonsi, F.;Ballabene, E.;Bellagamba, L.;Bianco, G.;Boscherini, D.;Bruni, A.;Carratta, G.;Clissa, L.;Cremonini, D.;De Castro, S.;Fabbri, F.;Fabbri, L.;Franchini, M.;Gabrielli, A.;Giacobbe, B.;Lasagni Manghi, F.;Massa, L.;Monzani, S.;