A Search For Resonant Production Of Tt Pairs In 4 8 Fb 1 Of Integrated Luminosity Of Pp Collisions At U221a S
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A Search for Resonant Production of Tt Pairs in 4.8 Fb-1 of Integrated Luminosity of Pp Collisions at {u221A}s
We search for resonant production of tt pairs in 4.8 fb-1 integrated luminosity of pp collision data at √s = 1.96 TeV in the lepton+jets decay channel, where one top quark decays leptonically and the other hadronically. A matrix element reconstruction technique is used; for each event a probability density function (pdf) of the tt candidate invariant mass is sampled. These pdfs are used to construct a likelihood function, whereby the cross section for resonant tt production is estimated, given a hypothetical resonance mass and width. The data indicate no evidence of resonant production of tt pairs. A benchmark model of leptophobic Z' → tt is excluded with mZ'
Search for Resonant $t\bar{t}$ Production in Proton-proton Collisions at {u221A}s
A search is performed for the production of heavy resonances decaying into top-antitop quark pairs in proton-proton collisions at √s = 8 TeV. Data used for the analyses were collected with the CMS detector and correspond to an integrated luminosity of 19.7 fb–1. The search is performed using events with three different final states, defined by the number of leptons (electrons and muons) from the tt¯ → WbWb decay. The analyses are optimized for reconstruction of top quarks with high Lorentz boosts, where jet substructure techniques are used to enhance the sensitivity. Results are presented for all channels and a combination is performed. Furthermore, no significant excess of events relative to the expected yield from standard model processes is observed.
Search for Resonant Production of Tt Decaying to Jets in Pp Collisions at {u221A}{s}
This Letter reports a search for non-standard model topquark resonances, Z', decaying to ttMs; →W+bW-b , where both W decay to quarks. We examine the top-antitop quark invariant mass spectrum for the presence of narrow resonant states. The search uses a data sample of p{bar p} collisions at a center of mass energy of 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron, with an integrated luminosity of 2.8 fb-1. No evidence for top-antitop quark resonant production is found. We place upper limits on the production cross section times branching ratio for a specific topcolor assisted technicolor model with width of ?Z' = 0.012 MZ'. Within this model, we exclude Z' boson with masses below 805 GeV/c2 at the 95% confidence level.