Speaker
Amitabha Das
(University of Arizona)
Description
We present a measurement of the helicity of the W boson produced in top quark decays using $t\bar{t}$ ~decays in the $\ell+$jets and dilepton final states selected from a sample of 5.4 fb$^{-1}$ of collisions recorded using the D0 detector at the Fermilab Tevatron $p\bar{p}$ collider. We measure the fractions of longitudinal and right-handed $W$ bosons to be $f_0 = 0.669 \pm 0.102 \mbox{ } [ \pm 0.078 \hbox{ (stat.)} \pm 0.065 \hbox{ (syst.)}]$ and $f_+ = 0.023 \pm 0.053\mbox{ }[\pm 0.041 \hbox{ (stat.)} \pm 0.034 \hbox{ (syst.)}]$, respectively. This result is consistent at the 98\% level with the standard model.
A measurement with $f_0$ fixed to the value from the standard model yields $f_+ = 0.010 \pm 0.037 \mbox{ }[\pm 0.022 \hbox{ (stat.)} \pm 0.030 \hbox{ (syst.). }]$
Primary author
Amitabha Das
(University of Arizona)
