A search is presented for the production of a single narrow-width vectorlike B′ quark that decays to a t quark and a W boson. This search targets a single-lepton final state, where a muon or electron originates either from the semileptonic decay of the t quark or from the leptonic decay of the W boson, with the other particle decaying hadronically. The (semi)leptonic portion of the event is reconstructed from an electron or muon, missing transverse momentum, and a small-radius jet identified as a b quark jet if the muon or electron originates from the t quark. The hadronic portion of the event is reconstructed as a single large-radius jet. The originating particle of the large-radius jet is identified using a neural-network-based tagger, and the dominant background contributions are modeled from data using a neural autoregressive flow network. The data were collected from 2016 to 2018 by the CMS experiment at the LHC in proton-proton collisions at s = 13 TeV, corresponding to an integrated luminosity of 138 fb−1. This search is the most sensitive to date to the production of single narrow-width B′ quarks. It excludes electroweak-singlet B′ quarks with Γ/mB′ = 5% for masses between 0.8 and 1.23 TeV. Limits are also placed on the production cross section of single B′ quarks produced in association with t quarks, and on the coupling factor of the B′ quark to electroweak bosons.
Search for single production of a vectorlike B ′ quark decaying to a top quark and a W boson in the single-lepton final state in proton-proton collisions at √ s = 13 TeV
Abbrescia, M.;Buonsante, M.;Colaleo, A.;De Palma, M.;Elmetenawee, W.;Generoso, L.;Louka, M.;My, S.;Nenna, F.;Nuzzo, S.;Pellecchia, A.;Pompili, A.;Radogna, R.;Simone, F. M.;Stamerra, A.;Troiano, D.;Venditti, R.;Zaza, A.;D'Anzi, B.;
2026-01-01
Abstract
A search is presented for the production of a single narrow-width vectorlike B′ quark that decays to a t quark and a W boson. This search targets a single-lepton final state, where a muon or electron originates either from the semileptonic decay of the t quark or from the leptonic decay of the W boson, with the other particle decaying hadronically. The (semi)leptonic portion of the event is reconstructed from an electron or muon, missing transverse momentum, and a small-radius jet identified as a b quark jet if the muon or electron originates from the t quark. The hadronic portion of the event is reconstructed as a single large-radius jet. The originating particle of the large-radius jet is identified using a neural-network-based tagger, and the dominant background contributions are modeled from data using a neural autoregressive flow network. The data were collected from 2016 to 2018 by the CMS experiment at the LHC in proton-proton collisions at s = 13 TeV, corresponding to an integrated luminosity of 138 fb−1. This search is the most sensitive to date to the production of single narrow-width B′ quarks. It excludes electroweak-singlet B′ quarks with Γ/mB′ = 5% for masses between 0.8 and 1.23 TeV. Limits are also placed on the production cross section of single B′ quarks produced in association with t quarks, and on the coupling factor of the B′ quark to electroweak bosons.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.


