Colour Reconnection at Future ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ Colliders

Abstract

The effects of colour reconnection (CR) at ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ colliders are revisited, with focus on recently developed CR models. The new models are compared with the LEP2 measurements for ${\mathrm{e}}^{+}{\mathrm{e}}^{-}\to {\mathrm{W}}^{+}{\mathrm{W}}^{-}\to {\mathrm{q}}_1{\overline{\mathrm{q}}}_2{\mathrm{q}}_3{\overline{\mathrm{q}}}_4$ and found to lie within their limits. Prospects for constraints from new high-luminosity ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ colliders are discussed. The novel arena of CR in Higgs decays is introduced, and illustrated by shifts in angular correlations that would be used to set limits on a potential $CP$-odd admixture of the 125 GeV Higgs state.

11 pages, 4 figures