Phenomenology of composite colored weak bosons

Abstract

In composite models of quarks, leptons and weak bosons whereW-constituents are colored objects, color octet partners ofW ^± andZ ⁰ are predicted. We study in detail the phenomenology of these particles. Independent of the specific model one expects a color octet isotriplet of vector bosons (W ^±₈ ,Z ⁰₈ ) with mass in the range of 100–200 GeV, and a color octet isosinglet vector bosonV ⁰₈ with substantially larger mass, due to mixing with the gluon. Moreover, relatively light color octet excitations of the leptons appear, while the existence of “color exotic” partners of the quarks is model dependent. These particles decay mainly into a lepton (quark) and a gluon. We construct the couplings ofW ^±₈ ,Z ⁰₈ andV ⁰₈ to ordinary and “color exotic” fermions. The signals of color octet weak bosons in low energy weak reactions are explored in detail. The production cross section ofW ^±₈ (Z ⁰₈ ) in hadron-hadron collisions is calculated for$0.54TeV \leqq \sqrt s \leqq 20TeV$. Various decay modes of colored weak bosons are studied. The most prominent decay signatures ofW ^±₈ andZ ⁰₈ are events of the type

(l ^+-: charged lepton;j: hadronic jet;

: missing transverse momentum). The present CERN$p\bar p$ collider data on such events are discussed in the light ofW ^±₈ andZ ⁰₈ decays. If colored weak bosons are not found with a mass less than ∼250 GeV composite model building will be strongly restricted.