Does the W Mass Reconstruction Survive QCD Effects?

Abstract

In the hadronic decay mode of a pair of W bosons, $\text{e}+\text{e}-\to \text{W}+\text{W}-\to {\text{q}}_1{\overline{\text{q}}}_2{\text{q}}_3{\overline{\text{q}}}_4$, QCD interference effects can mix up the two colour singlets ${\text{q}}_1{\overline{\text{q}}}_2$ and ${\text{q}}_3{\overline{\text{q}}}_4$, i.e. produce hadrons that cannot be uniquely assigned to either of W$+$ and W$-$. We show that interference is negligible for energetic perturbative gluon emission, and develop models to help us to estimate the non-perturbative effects. The total contribution to the systematic error on the W mass reconstruction may be as large as 40 MeV.

Comments: 6 pages, CERN Preprint CERN-TH.9043/93, Durham preprint DTP/93/84