Search for charged-lepton-flavor violating μ τ q t interactions in top-quark production and decay in p p collisions at s = 13     TeV with the ATLAS detector at the LHC

• Published in: Physical review. D 2024-07, Vol.110 (1)
• Main Authors: Acharya, B. S., Agaras, M. N., Baer, T. M., Balunas, W. K., Barel, M. Z., Biglietti, M., Bortoletto, D., Brau, J. E., Bruckler, T. L., Calfayan, P., Campanelli, M., Catmore, J. R., Che, Y., Corpe, L. D., Cueto, A., Dabrowski, W., Dattola, F., David, C., De Santis, F., Delitzsch, C. M., Delsart, P. A., Derendarz, D., Dona, K. M., Drnevich, M., Drozdova, M., Dubovsky, M., Duckeck, G., Earnshaw, Z. O., El Moussaouy, A., Freund, W. S., Gentry, A. D., Ghani, M., Gillberg, D., Gonzalez-Sevilla, S., Goshaw, A. T., Hagan, A. I., Hahn, J. J., Harenberg, T., Hartmann, N. M., Hirose, M., Karava, K., Kay, E. F., Keszeghova, L., Kocian, M., Koletsou, I., Kortman, B., Koulouris, A., Kresse, T., Kuehn, S., Kumar, M., Kurashige, H., Lampl, W., Li, M., Li, S., Lu, G., Majersky, O., Martinez Suarez, P., Mehlhase, S., Morettini, P., Muškinja, M., Ovsiannikova, T., Patel, U. M., Penzin, M., Petousis, V., Prokofiev, K., Przybycien, M., Qian, J., Ramakoti, E., Rinn, T. T., Rottler, B., Rozen, Y., Saraiva, J. G., Schäfer, U., Schernau, M., Schioppa, M., Schmeing, J., Schoeffel, L., Shen, Q., Shroff, M. J., Silva, J. M., Siral, I., Skorda, E., Smakhtin, V., Steentoft, J., Strandberg, J., Talby, M., Thomas, J. P., Tikhomirov, V., Torres, H., Tsiskaridze, V., Wagner, J. M., Wang, C., Wang, Y., Watson, M. F., Wharton, A. M., Wilson, B. J., Xu, R., Yabsley, B., Yan, Z., Zhang, J.
• Format: Article
• Language: English
• ISSN: 2470-0010

A search for charged-lepton-flavor violating μ τ q t ( q = u , c ) interactions is presented, considering both top-quark production and decay. The data analyzed correspond to 140     fb − 1 of proton-proton collisions at a center-of-mass energy of s = 13     TeV recorded with the ATLAS detector at the Large Hadron Collider. The analysis targets events containing two muons with the same electric charge, a hadronically decaying τ -lepton and at least one jet, with exactly one b -tagged jet, produced by a μ τ q t interaction. Agreement with the Standard Model expectation within 1.6 standard deviations is observed, and limits are set at the 95% confidence level (CL) on the charged-lepton-flavor violation branching ratio of B ( t → μ τ q ) < 8.7 × 10 − 7 . An effective field theory interpretation is performed yielding 95% CL limits on Wilson coefficients, dependent on the flavor of the associated light quark and the Lorentz structure of the coupling. These range from | c lequ 3 ( 2313 ) | / Λ 2 < 0.10     TeV − 2 for μ τ u t to | c lequ 1 ( 2323 ) | / Λ 2 < 1.8     TeV − 2 for μ τ c t . An additional interpretation is performed for scalar leptoquark production inducing charged-lepton-flavor violation, with fixed intergenerational couplings. Upper limits on leptoquark coupling strengths are set at the 95% CL, ranging from λ LQ = 1.3 to λ LQ = 3.7 for leptoquark masses between 0.5 and 2.0 TeV. © 2024 CERN, for the ATLAS Collaboration 2024 CERN