The European Physical Journal C > 2019 > 79 > 4 > 1-31
Search for vector-like quarks in events with two oppositely charged leptons and jets in proton–proton collisions at $$\sqrt{s} = 13\,\text {Te}\text {V} $$ s=13Te
Source
Abstract
A search for the pair production of heavy vector-like partners $$\mathrm {T}$$ T and $$\mathrm {B}$$ B of the top and bottom quarks has been performed by the CMS experiment at the CERN LHC using proton–proton collisions at $$\sqrt{s} = 13\,\text {Te}\text {V} $$ s=13Te . The data sample was collected in 2016 and corresponds to an integrated luminosity of 35.9$$\,\text {fb}^{-1}$$ fb-1 . Final states studied for $$\mathrm {T} \overline{\mathrm {T}} $$ TT¯ production include those where one of the $$\mathrm {T}$$ T quarks decays via $$\mathrm {T} \rightarrow \mathrm {t}\mathrm {Z}$$ T→tZ and the other via $$\mathrm {T} \rightarrow \mathrm {b}\mathrm {W}$$ T→bW , $$\mathrm {t}\mathrm {Z}$$ tZ , or $$\mathrm {t}\mathrm {H} $$ tH , where $$\mathrm {H}$$ H is a Higgs boson. For the $$\mathrm {B} \overline{\mathrm {B}} $$ BB¯ case, final states include those where one of the $$\mathrm {B}$$ B quarks decays via $$\mathrm {B} \rightarrow \mathrm {b}\mathrm {Z}$$ B→bZ and the other $$\mathrm {B} \rightarrow \mathrm {t}\mathrm {W}$$ B→tW , $$\mathrm {b}\mathrm {Z}$$ bZ , or $$\mathrm {b}\mathrm {H} $$ bH . Events with two oppositely charged electrons or muons, consistent with coming from the decay of a $$\mathrm {Z}$$ Z boson, and jets are investigated. The number of observed events is consistent with standard model background estimations. Lower limits at 95% confidence level are placed on the masses of the $$\mathrm {T}$$ T and $$\mathrm {B}$$ B quarks for a range of branching fractions. Assuming 100% branching fractions for $$\mathrm {T} \rightarrow \mathrm {t}\mathrm {Z}$$ T→tZ , and $$\mathrm {B} \rightarrow \mathrm {b}\mathrm {Z}$$ B→bZ , $$\mathrm {T}$$ T and $$\mathrm {B}$$ B quark mass values below 1280 and 1130$$\,\text {Ge}\text {V}$$ Ge , respectively, are excluded.
Identifiers
journal ISSN : | 1434-6044 |
journal e-ISSN : | 1434-6052 |
DOI | 10.1140/epjc/s10052-019-6855-8 |