W'-like Resonances in the tb Decay Channel with 1.9 fb-1

Dan Amidei, J. Clark Cully (University of Michigan)
Catalin Ciobanu (Illinois - Urbana-Champaign)
Peter Dong, Bernd Stelzer, Rainer Wallny (UCLA)

Email Authors


Public Result:  MW' > 800 GeV/c2   (MW' > MνR)   and   MW' > 825 GeV/c2   (MW' < MνR)

Published in Phys. Rev. Lett. 103, 041801 (2009)


Abstract:
We use the tools of the single top analysis to search for resonant tb (+c.c) pair production in 1.9 fb-1 sample of pp collisions. For b-tagged events in the W+2 and W+3 jets channels, we look for unexpected structure in the spectrum of MWjj, the total invariant mass of the reconstructed W boson and two leading jets. 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 σ * BR to tb as a function of the W' mass and compare to expectation.

Additional Documentation:

        Public Note 9150 (ps) (pdf)
        Theory of a Standard Model W' (ps)


Limits:

Observed Mass Limits (Left) and Closeup of Mass Limits (Right)



Observed Limits on Coupling Strength (Left) and Check of Fit Linearity (Right)



Expected Limits Among Channelsn(Left) and Expected Limits Among Lepton Types (Right)



Expected Limits for Various Systematics (Left) and Projected Limits (Right)




Shape Templates:

Signal Shape Comparison (Left) and W+b like Templates (Right)



Signal Shape Comparison (Left) and W+b like Templates (Right)



Signal Shape Comparison (Left) and W+b like Templates (Right)




Validation Plots:

Signal: MWJJ




Lepton PT



MET (&nu PT)



Lead Jet ET



W Tranverse Mass