Journal Article

Search for heavy neutral leptons in decays of W bosons using leptonic and semi-leptonic displaced vertices in s = 13 TeV pp collisions with the ATLAS detector

Walkowiak, W., Raine, J. A., 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., 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., M. Soberi, M. Firdaus, 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., Kupfer, T., Principe Martin, M. A., Berthold, A., Pintucci, L., Thornberry, R. E., 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., Tariq, K., Huang, S., Junkermann, T., Veloso, F., Zhang, R., Tikhomirov, V., Dervan, P., Nelson, K., Aboelela, M., Davidek, T., Kivernyk, O., Amo

2025

Overview

A bstract A search is performed for long-lived heavy neutral leptons (HNLs), produced through the decay of a W boson along with a muon or electron. Two channels are explored: a leptonic channel, in which the HNL decays into two leptons and a neutrino, and a semi-leptonic channel, in which the HNL decays into a lepton and a charged pion. The search is performed with 140 fb − 1 of s = 13 TeV proton-proton collision data collected by ATLAS during Run 2 of the Large Hadron Collider. No excess of events is observed; Dirac-like and Majorana-like HNLs with masses below 14.5 GeV and mixing coefficients as small as 10 − 7 are excluded at the 95% confidence level. The results are interpreted under different assumptions on the flavour of the leptons from the HNL decays.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V,Springer Nature
• Subject: Apexes / Beyond Standard Model / Bosons / Charged particles / Classical and Quantum Gravitation / Collaboration / Confidence intervals / Elementary Particles / Exotics / Flavor (particle physics) / FOS: Physical sciences / Hadron-Hadron Scattering / High Energy Physics - Experiment (hep-ex) / Large Hadron Collider / Leptons / LHC / LLP / Neutrinos / Physics / Physics and Astronomy / PHYSICS OF ELEMENTARY PARTICLES AND FIELDS / Pions / Protons / Quantum Field Theories / Quantum Field Theory / Quantum Physics / Regular Article - Experimental Physics / Relativity Theory / Searching / Sensors / Simulation / String Theory