Journal Article

Search for resonant leptoquark production via lepton-jet signatures in pp collisions at√s̅=13TeV and√s̅=13.6TeV with the ATLAS detector

Walkowiak, W., Garcia Alonso, A., Watson, H., Introzzi, G., Arbiol Val, S. J., Pan, J., Gao, Y., Strom, D. M., Albouy, G. L., Meyer, J-P., Ling, J., Ezhilov, A., Mo, C., Fabbri, L., Jia, H., Carminati, L., Cantero, J., Hsu, S.-C., Pedro, R., Carlotto, J. I., Meyer, C., Guerrieri, G., Mellado Garcia, B. R., Mulski, A. E., Zhang, P., Diaz, M. A., Dudarev, A., Shi, X., Atmani, H., Borissov, G., Kajomovitz, E., Brüers, B., Moyano Gomez, H., Yang, Y., Algren, M., Catmore, J. R., Calafiura, P., Garg, R. B., Gonzalez-Sevilla, S., Korn, A., Shaheen, R., Bhopatkar, V. S., Simpson, E. L., Hessey, N. P., Inacio Goncalves, G., Zhang, S., Grabarczyk, R. P., Zhukov, K., Golubkov, D., Kang, N. J., Krüger, H., Principe Martin, M. A., Berthold, A., Pintucci, L., Thornberry, R. E., Hamdaoui, H., Gazis, E. N., Vokac, P., Hawkings, R. J., Busch, E. L., Melo, A. H., Yang, X., Kim, Y. K., Tu, Y., Schwarz, T. A., De Almeida Rossi, C., Calace, N., Zoccoli, A., Jia, J., Viehhauser, G. H. A., Pettee, M., Revering, M. M., Tariq, K., Huang, S., Junkermann, T., Veloso, F., Zhang, R., Tikhomirov, V., Dervan, P., Nelson, K., Aboelela, M., Davidek, T., Taylor Vara, R. J., Kiverny

2025

Overview

This paper presents a search for physics beyond the Standard Model targeting a heavy resonance visible in the invariant mass of the lepton-jet system. The analysis focuses on final states with a high-energy lepton and jet, and is optimised for the resonant production of leptoquarks — a novel production mode mediated by the lepton content of the proton originating from quantum fluctuations. Four distinct and orthogonal final states are considered: e+light jet, μ+light jet, e+b-jet, and μ+b-jet, constituting the first search at the Large Hadron Collider for resonantly produced leptoquarks with couplings to electrons and muons. Events with an additional same-flavour lepton, as expected from higher-order diagrams in the signal process, are also included in each channel. The search uses proton-proton collision data from the full Run 2, corresponding to an integrated luminosity of 140 fb−1 at a centre-of-mass energy of √s̅=13 TeV, and from a part of Run 3 (2022–2023), corresponding to 55 fb−1 at √s̅=13.6 TeV. No significant excess over Standard Model predictions is observed. The results are interpreted as exclusion limits on scalar leptoquark (S̃1) production, substantially improving upon previous ATLAS constraints from leptoquark pair production for large coupling values. The excluded S̃1 S̃1 mass ranges depend on the coupling strength, reaching up to 3.4 TeV for quark-lepton couplings yde = 1.0, and up to 4.3 TeV, 3.1 TeV, and 2.8 TeV for ysμ, ybe, and ybμ couplings set to 3.5, respectively.

• Publisher: Springer Science and Business Media LLC
• Subject: Hadron-Hadron Scattering