Göttingen 2025 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
T: Fachverband Teilchenphysik
T 93: Top Physics IV (Misc.)
T 93.4: Vortrag
Freitag, 4. April 2025, 09:45–10:00, VG 1.103
Search for heavy right-handed Majorana neutrinos in the decay of top quarks produced in proton–proton collisions at √s = 13 TeV with the ATLAS detector — •Diptaparna Biswas1, Markus Cristinziani1, Nikolina Ilic2, Lianliang Ma3, Oğul Öncel4, Sebastien Roy-Garand2, Mário José da Cunha Sargedas de Sousa5,6, and Tongbin Zhao1,3 — 1Experimentelle Teilchenphysik, Center for Particle Physics Siegen, Universität Siegen, Germany — 2University of Toronto, Canada — 3Shandong University, China — 4Albert-Ludwigs-Universität Freiburg, Germany — 5INFN Genova, Italy — 6Università di Genova, Italy
A search for heavy right-handed Majorana neutrinos is performed with the ATLAS detector at the CERN Large Hadron Collider, using the Run-2 dataset. This search targets tt production, in which both top quarks decay into a bottom quark and a W boson, where one of the W bosons decays hadronically and the other decays into an electron or muon and a heavy neutral lepton. The heavy neutral lepton is identified through a decay into an electron or muon and another W boson, resulting in a pair of same-charge same-flavor leptons in the final state. This talk presents a search for heavy neutral leptons in the mass range of 15−75 GeV using tt events. No significant excess is observed over the background expectation, and upper limits are placed on the signal cross-sections. Assuming a benchmark scenario of the phenomenological type-I seesaw model, these cross-section limits are then translated into upper limits on the mixing parameters of the heavy Majorana neutrino with Standard Model neutrinos.
Keywords: Top quark decay; Top pair; Heavy neutrinos; Majorana neutrinos; HNL