Search for single production of a vector-like T quark decaying to a Z boson and a top quark in proton-proton collisions at $\\sqrt s$ = 13 TeV
Journal
Physics Letters
Journal Volume
B781
Pages
574-600
Date Issued
2018
Author(s)
Sirunyan, A. M. et al.
Abstract
A search is presented for single production of a vector-like quark (T) decaying to a Z boson and a top quark, with the Z boson decaying leptonically and the top quark decaying hadronically. The search uses data collected by the CMS experiment in proton-proton collisions at a center-of-mass energy of 13 TeV in 2016, corresponding to an integrated luminosity of 35.9 fb -1 . The presence of forward jets is a particular characteristic of single production of vector-like quarks that is used in the analysis. For the first time, different T quark width hypotheses are studied, from negligibly small to 30% of the new particle mass. At the 95% confidence level, the product of cross section and branching fraction is excluded above values in the range 0.26-0.04 pb for T quark masses in the range 0.7-1.7 TeV, assuming a negligible width. A similar sensitivity is observed for widths of up to 30% of the T quark mass. The production of a heavy Z boson decaying to Tt, with T tZ, is also searched for, and limits on the product of cross section and branching fractions for this process are set between 0.13 and 0.06 pb for Z boson masses in the range from 1.5 to 2.5 TeV.
SDGs
Type
journal article