New Strong Interactons at the Tevatron ?

TL;DR

The study addresses an apparent excess in high-$E_T$ jet production reported at the Tevatron and proposes a minimal, flavor-universal coloron framework based on the gauge group $SU(3)_1 \times SU(3)_2$ with a bifundamental scalar that breaks to QCD, yielding colorons of mass $M_C$ and a low-energy four-fermion interaction. It analyzes two realizations—Higgs and confining phases—showing that coloron exchange can improve the jet data fit relative to QCD and that the angular distributions differ depending on the phase, with predictions of TeV-scale resonances at the LHC. The model is presented as a useful baseline for data comparison and for exploring quark compositeness if global chiral symmetries remain unbroken, while noting that it does not address electroweak or flavor symmetry breaking and thus invites further model-building, such as composite technicolor–type extensions. Overall, it provides a minimal, testable framework for interpreting high-$E_T$ jet excesses and guiding experimental searches for new strong dynamics at the TeV scale, including flavor-universal contact interactions and vector/axial resonances.

Abstract

Recent results from CDF indicate that the inclusive cross section for jets with $E_T > 200$ GeV is significantly higher than that predicted by QCD. We describe here a simple flavor-universal variant of the ``coloron" model of Hill and Parke that can accommodate such a jet excess, and which is not in contradiction with other experimental data. As such, the model serves as a useful baseline with which to compare both the data and other models proposed to describe the jet excess. An interesting theoretical feature of the model is that if the global chiral symmetries of the quarks remain unbroken in the confining phase of the coloron interaction, it realizes the possibility that the ordinary quarks are composite particles.

Figures (1)

• Figure 1: Single jet inclusive cross-section ${1\over{\Delta\eta}} \int (d^2\sigma/d\eta\, dE_T) d\eta$ as a function of transverse jet energy $E_t$, where the pseudorapidity $\eta$ of the jet falls in the range $0.1 \leq \vert\eta\vert \leq 0.7$. Dots with (statistical) error bars are the recently published CDF data cdff. The solid curve shows the LO prediction of pure QCD. The dashed curve shows the LO prediction of QCD plus the color-octet contact interactions of equation (\ref{['eqn:higgs']}) with $M_C/\cot\theta = 700$ GeV. Following CDF, we employed the MRSD0' structure functions mrs_pak and we normalized the curves to the data in the region where the effect of the contact interactions is small (here this region is $45 < E_T < 95$ GeV). The upper plot shows the full transverse-energy range; the lower plot shows more detail of the high-energy range $E_T > 200$ GeV.