Consistency and interpretation of the LHC dijet excesses

Abstract

ATLAS observed a limit for the cross section of dijet resonances, which is weaker than expected for a mass slightly below ≈1 TeV. In addition, CMS reported hints for the (nonresonant) pair production of dijet resonances X via a particle Y at a very similar mass range with a local (global) significance of 3.6σ (2.5σ) at mX ≈ 950 GeV. In this article, we show that, using the preferred range for mX from the ATLAS analysis, one can reinterpret the CMS analysis of didijets in terms of a resonant search with Y → XX, with a significantly reduced look-elsewhere effect, finding an excess for mY ≈ 3.6 TeV with a significance of 4.0σ (3.2σ) locally (globally). We present two possible UV completions capable of explaining the (di)dijet excesses, one containing two scalar diquarks, the other one involving heavy gluons based on an SUð3Þ1 × SUð3Þ2 × SUð3Þ3 gauge symmetry, spontaneously broken to SUð3Þ color. In the latter case, nonperturbative couplings are required, pointing toward a composite or extradimensional framework. In fact, using 5D anti–de Sitter space-time, one obtains the correct mass ratio for mX=mY, assuming the X is the lowest-lying resonance, and predicts a third (di)dijet resonance with a mass around ≈2.2 TeV.