The European Physical Journal C > 2019 > 79 > 3 > 1-32
Search for a heavy resonance decaying to a top quark and a vector-like top quark in the lepton + jets final state in pp collisions at $$\sqrt{s} = 13\,\text {TeV} $$ s=13TeV
Source
Abstract
A search is presented for a heavy spin-1 resonance $$\mathrm {Z}'$$ Z′ decaying to a top quark and a vector-like top quark partner $$\text {T} $$ T in the lepton + jets final state. The search is performed using a data set of $$\mathrm {p}$$ p $$\mathrm {p}$$ p collisions at a centre-of-mass energy of 13$$\,\text {TeV}$$ TeV corresponding to an integrated luminosity of $$35.9{\,\text {fb}^{-1}} $$ 35.9fb-1 as recorded by the CMS experiment at the CERN LHC in the year 2016. The analysis is optimised for final states arising from the $$\text {T} $$ T decay modes to a top quark and a Higgs or $$\mathrm {Z}$$ Z boson ($$\text {T} \rightarrow \mathrm {H} \mathrm {t}, \mathrm {Z} \mathrm {t}$$ T→Ht,Zt ). The event selection makes use of resolved and merged top quark decay products, as well as decays of boosted Higgs bosons and $$\mathrm {Z}$$ Z and $$\mathrm {W}$$ W bosons using jet substructure techniques. No significant deviation from the standard model background expectation is observed. Exclusion limits on the product of the cross section and branching fraction for $$\mathrm {Z}'\rightarrow \mathrm {t}\text {T}, \text {T} \rightarrow \mathrm {H} \mathrm {t}, \mathrm {Z} \mathrm {t}, \mathrm {W}\mathrm {b}$$ Z′→tT,T→Ht,Zt,Wb are presented for various combinations of the $$\mathrm {Z}'$$ Z′ resonance mass and the vector-like $$\text {T} $$ T quark mass. These results represent the most stringent limits to date for the decay mode $$\mathrm {Z}'\rightarrow \mathrm {t}\text {T} \rightarrow \mathrm {t}\mathrm {H} \mathrm {t}$$ Z′→tT→tHt . In a benchmark model with extra dimensions, invoking a heavy spin-1 resonance $$\mathrm {G}^* $$ G∗ , masses of the $$\mathrm {G}^* $$ G∗ between 1.5 and 2.3$$\,\text {TeV}$$ TeV and between 2.0 and 2.4$$\,\text {TeV}$$ TeV are excluded for $$\text {T} $$ T masses of 1.2 and 1.5$$\,\text {TeV}$$ TeV , respectively.
Identifiers
journal ISSN : | 1434-6044 |
journal e-ISSN : | 1434-6052 |
DOI | 10.1140/epjc/s10052-019-6688-5 |