Search for the rare radiative decay $W\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\gamma}$ in $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$

Search for the rare radiative decay $W \to π γ$ in $p \bar{p}$ collisions at $\sqrt{s} = 1.96 TeV$

T. Aaltonen et al. (CDF Collaboration)

Phys. Rev. D 85, 032001 – Published 2 February 2012

Abstract

We present a search for the rare radiative decay $W^{\pm} \to π^{\pm} γ$ using data corresponding to an integrated luminosity of $4.3 {fb}^{- 1}$ of proton-antiproton collisions at a center-of-mass energy of 1.96 TeV collected by the CDF experiment at Fermilab. As no statistically significant signal is observed, we set a 95%-confidence-level upper limit on the relative branching fraction $Γ (W^{\pm} \to π^{\pm} γ) / Γ (W^{\pm} \to e^{\pm} ν)$ at $6.4 \times 10^{- 5}$ , a factor of 10 improvement over the previous limit.