W'-like Resonances in the tb Decay Channel with 1 fb-1


J. Clark Cullya, Jason Slaunwhiteb, Dan Amideia, Catalin Ciobanuc, Richard Hughesb,
Tom Junkc, Kevin Lannonb, Veronica Sorind, Kirsten Tollefsond, Brian Winerb

aUniversity of Michigan
bThe Ohio State University
cUniversity of Illinois at Urbana-Champaign
dMichigan State University

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Public Result:  MW' > 760 GeV/c2   (MW' > M&nuR)   and   MW' > 790 GeV/c2   (MW' < M&nuR)

Abstract:

We use the tools of the single top analysis to search for resonant tb (+c.c) pair production in a sample of approximately 1 fb-1 of pp collisions at the Fermilab Tevatron. We look for unexpected structure in the spectrum of the invariant mass of the reconstructed W boson and two leading jets: MWjj. Expected contributions from Standard Model (SM) processes are derived from selections and background studies of the single top analysis. Resonant tb production is modeled as a simple W' with SM-like couplings to fermions. We establish expected sensitivity over the W' mass range from 300 GeV/c2 to 950 GeV/c2, derive 95% CL upper limits for &sigma * BR to tb as a function of the W' mass and compare to expectation.

Documentation: Public Note 8747

Expected Limits for 2+3 Jets (Left) and
Comparison to 2 Jets and 3 Jets Alone (Right)



Combined 2+3 Jet Observed Limits



Observed Limit of Fermion Coupling



2 Jets Only (Left) and 3 Jets Only (Right)



2+3 Jet Electrons Only (Left) and Muons Only (Right)



Signal: WJJ Mass



Validation: Lepton Pt
(BG scaled up 10% for visual comparision)



Validation: &nu Pt (MET)
(BG scaled up 10% for visual comparision)



Validation: Lead Jet Et
(BG scaled up 10% for visual comparision)



Validation: Second Jet Et
(BG scaled up 10% for visual comparision)



Validation: W Tranverse Mass
(BG scaled up 10% for visual comparision)



For W' of 500 GeV/c2:


Best Fit to the Data for Null and Test Hypothesis
in 2 Jets (Left) and 3 Jets (Right)



Comparision of 600 GeV/c2 to Expectation in 2 Jets (Left) and 3 Jets (Right)



Event Tables:


Method II Background Expectation



Number of W's Events Predicted by Theory (at NLO)
if decays to leptons are allowed (Left) and if decays to leptons are forbidden (Right)