Search for excited quarks in<i>pp¯</i>collisions at √<i>s</i>=1.8 TeV

Abstract

If quarks are composite particles then excited states are expected. We have searched in pp\ifmmode\bar\else\textasciimacron\fi{} collisions for excited quarks (${\mathit{q}}^{\mathrm{*}}$) which decay to common quarks by emitting a W boson (${\mathit{q}}^{\mathrm{*}}$\ensuremath{\rightarrow}qW) or a photon (${\mathit{q}}^{\mathrm{*}}$\ensuremath{\rightarrow}q\ensuremath{\gamma}). The simplest model of excited quarks has been excluded for mass ${\mathit{M}}^{\mathrm{*}}$540 GeV/${\mathit{c}}^{2}$ at 95% confidence level.