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 s=13 TeV, and from a part of Run 3 (2022–2023), corresponding to 55 fb−1 at s=13.6 TeV. No significant excess over Standard Model predictions is observed. The results are interpreted as exclusion limits on scalar leptoquark S~1 production, substantially improving upon previous ATLAS constraints from leptoquark pair production for large coupling values. The excluded S~1 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.

Search for resonant leptoquark production via lepton-jet signatures in pp collisions at s=13 TeV and s=13.6 TeV with the ATLAS detector / Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.J., Abidi, S.H., Aboelela, M., Aboulhorma, A., Abramowicz, H., Abulaiti, Y., Acharya, B.S., Ackermann, A., Adam Bourdarios, C., Adamczyk, L., Addepalli, S.V., Addison, M.J., Adelman, J., Adiguzel, A., Adye, T., et al.. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1029-8479. - 2025:12(2025). [10.1007/JHEP12(2025)180]

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

Aloisio A.;Canale V.;Casolaro P.;Cirotto F.;D'Avanzo A.;Della Pietra M.;Iengo P.;Massarotti P.;Rossi E.;
2025

Abstract

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 s=13 TeV, and from a part of Run 3 (2022–2023), corresponding to 55 fb−1 at s=13.6 TeV. No significant excess over Standard Model predictions is observed. The results are interpreted as exclusion limits on scalar leptoquark S~1 production, substantially improving upon previous ATLAS constraints from leptoquark pair production for large coupling values. The excluded S~1 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.
2025
Search for resonant leptoquark production via lepton-jet signatures in pp collisions at s=13 TeV and s=13.6 TeV with the ATLAS detector / Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.J., Abidi, S.H., Aboelela, M., Aboulhorma, A., Abramowicz, H., Abulaiti, Y., Acharya, B.S., Ackermann, A., Adam Bourdarios, C., Adamczyk, L., Addepalli, S.V., Addison, M.J., Adelman, J., Adiguzel, A., Adye, T., et al.. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1029-8479. - 2025:12(2025). [10.1007/JHEP12(2025)180]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/1027044
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