Search for Production of Heavy Particles Decaying to Top Quarks and Invisible Particles in pp[over-bar] Collisions at [sqrt]s=1.96 TeV

• Main Authors: Bauer, Gerry P. (Contributor), Gomez-Ceballos, Guillelmo (Contributor), Goncharov, Maxim (Contributor), Makhoul, Khaldoun (Contributor), Paus, Christoph M. E. (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2011-11-28T21:34:47Z.
• Subjects: Article
• Online Access: Get fulltext

 We present a search for a new particle T' decaying to top quark via T'-->t+X, where X is an invisible particle. In a data sample with 4.8  fb[superscript -1] of integrated luminosity collected by the CDF II detector at Fermilab in pp[over-bar] collisions with [sqrt]s=1.96  TeV, we search for pair production of T' in the lepton+jets channel, pp[over-bar] -->tt[over-bar] +X+X-->ℓνbqq'b+X+X. We interpret our results primarily in terms of a model where T' are exotic fourth generation quarks and X are dark matter particles. Current direct and indirect bounds on such exotic quarks restrict their masses to be between 300 and 600  GeV/c[superscript 2], the dark matter particle mass being anywhere below mT'. The data are consistent with standard model expectations, and we set 95% confidence level limits on the generic production of T'T[over-bar] '-->tt[over-bar] +X+X. For the dark matter model we exclude T' at 95% confidence level up to mT'=360  GeV/c[superscript 2] for mX[less than or equal to]100  GeV/c[superscript 2].