2023 Articles

Search for pair production of third-generation leptoquarks decaying into a bottom quark and a 𝜏-lepton with the ATLAS detector

Aad, G.; Abbott, B.; Abeling, K.; Abidi, S. H.; Aboulhorma, A.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Hoffman, A. C. A.; Acharya, B. S.; Bourdarios, C. A.; 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.; Ahuja, S.; Ai, X.; Aielli, G.; Tamlihat, M. A.; Aitbenchikh, B.; Aizenberg, I.; Akbiyik, M.; Åkesson, T. P. A.; Akimov, A. V.; Khoury, K. A.; Alberghi, G. L.; Albert, J.

A search for pair-produced scalar or vector leptoquarks decaying into a 𝑏-quark and a 𝜏-lepton is presented using the full LHC Run 2 (2015–2018) data sample of 139 fb⁻¹ collected with the ATLAS detector in proton–proton collisions at a centre-of-mass energy of √𝒔 = 13 TeV. Events in which at least one 𝜏-lepton decays hadronically are considered, and multivariate discriminants are used to extract the signals.

No significant deviations from the Standard Model expectation are observed and 95% confidence-level upper limits on the production cross-section are derived as a function of leptoquark mass and branching ratio 𝓑 into a 𝜏-lepton and 𝑏-quark. For scalar leptoquarks, masses below 1460 GeV are excluded assuming 𝓑=100% while for vector leptoquarks the corresponding limit is 1650 GeV (1910 GeV) in the minimal-coupling (Yang–Mills) scenario.