Coloron Phenomenology

A flavor-universal extension of the strong interactions was recently proposed in response to the apparent excess of high-ET jets in the inclusive jet spectrum measured at the Tevatron. This paper studies the color octet of massive gauge bosons (‘colorons’) that is present in the low-energy spectrum of the model’s Higgs phase. Constraints from searches for new particles decaying to dijets and from measurements of the weak-interaction ρ parameter imply that the colorons must have masses greater than 870-1000 GeV. The implications of recent Tevatron data and the prospective input from future experiments are also discussed. e-mail address: [email protected] A flavor-universal coloron model [1] was recently proposed to explain the apparent excess of high-ET jets in the inclusive jet spectrum measured by CDF [2]. This model is a flavor-universal variant of the coloron model of Hill and Parke [3] which can accommodate the jet excess without contradicting other experimental data. It involves a minimal extension of the standard description of the strong interactions, including the addition of one gauge interaction and a scalar multiplet, but no new fermions. Furthermore, the flavor-universal coloron model of the strong interactions can be grafted onto the standard one-Higgs-doublet model of electroweak physics, yielding a simple, complete, and renormalizable theory. The model serves as a useful baseline with which to compare both the data and other candidate explanations of the jet excess. The latter include such diverse physics as modified parton distribution functions [4], higher-order contributions from gluon resummation [5], phenomenological models of quark substructure [2], new strongly-coupled Z ′ gauge bosons [6], quark resonances [7], non-standard triplegauge vertices [8], and light gluinos [9]. This letter explores the phenomenology of the Higgs phase of the model, in which an octet of strongly-interacting massive gauge bosons (colorons) is present in the low-energy spectrum. Previous work on this model has considered effects on the inclusive jet spectrum [1] and the dijet spectrum and angular distributions [10] in the approximation where coloron exchange is treated as a four-fermion contact interaction. The four-fermion approximation is appropriate for heavy colorons and conveniently allows the model’s effects to be represented in terms of a single parameter: the coefficient of the contact interaction. The present work goes beyond the four-fermion approximation by including propagating colorons of finite width. This allows us to investigate the phenomenology of colorons too light to be welldescribed by contact interactions at Tevatron energies. It also enables us to explore the separate dimensions of the coloron parameter space (mass and mixing angle) independently. We begin by reviewing the main features of the model, in both the Higgs and confining phases. Then, focusing on the Higgs phase, we discuss the effect that the presence of colorons strongly coupled to quarks will have on partonic scattering cross-sections. In section 3, we show what limits may already be placed on the mass and mixing angle of the colorons. Next, we discuss how further experiments can probe the model at higher coloron masses. Our conclusions appear in section 5.