Adair, A.Boulahouache, C.Ecklund, K.M.Geurts, F.J.M.Padley, B.P.Redjimi, R.Roberts, J.Zabel, J.2015-09-022015-09-022011Adair, A., Boulahouache, C., Ecklund, K.M., et al.. "Search for a Vectorlike Quark with Charge 2/3 in t+Z Events from pp Collisions at √s=7  TeV." <i>Physical Review Letters,</i> 107, no. 27 (2011) American Physical Society: 271802. http://dx.doi.org/10.1103/PhysRevLett.107.271802.https://hdl.handle.net/1911/81617A search for pair-produced heavy vectorlike charge-2/3 quarks, T, in pp collisions at a center-of-mass energy of 7 TeV, is performed with the CMS detector at the LHC. Events consistent with the flavor-changing-neutral-current decay of a T quark to a top quark and a Z boson are selected by requiring two leptons from the Z-boson decay, as well as an additional isolated charged lepton. In a data sample corresponding to an integrated luminosity of 1.14  fb−1, the number of observed events is found to be consistent with the standard model background prediction. Assuming a branching fraction of 100% for the decay T→tZ, a T quark with a mass less than 475  GeV/c2 is excluded at the 95% confidence level.engThis is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Journal articlehttp://dx.doi.org/10.1103/PhysRevLett.107.271802