Public Analysis Web Page
CDF Combination of Measurements of W-Boson Helicity Fractions in Top-Quark Decays using cosThetaStar
R. Eusebi, D. Glenzinski, A. Hocker (FNAL)
S. Moed (Harvard)
T. Chwalek, D. Hirschbuehl, T. Mueller, W. Wagner, J. Wagner-Kuhr (Karlsruhe)
Abstract:
Two analyses have measured the W helicity fractions in top quark decays
by reconstructing the angle (cosThetaStar) between the lepton as measured
in the W rest frame and the W boson flight direction in the top rest frame
using 1.9 fb-1 of collision data. All the details, pretty
pictures, etc. can be found at the public pages for these individual
analyses (here
and here) and
in the public note linked below.
The results of these two analyses have been combined using BLUE to yield
f_0 = 0.62 ± 0.11 assuming f_+ = 0.0 (the SM value)
f_+ = -0.04 ± 0.05 assuming f_0 = 0.7 (the SM value)
f_0 = 0.66 ± 0.16 and f_+ = -0.03 ± 0.07, correlation coeff = -0.82 with no assumption
public note (CDF 9431) Measurement of W Boson Helicity Fractions in
Top Quark Decays
Using cosThetaStar