Heavy octets and Tevatron signals with three or four b jets

Abstract

Hypothetical color-octet particles of spin 0, pair-produced at hadron colliders through their QCD coupling, may lead to final states involving three or four b jets. The scalar octets may also be resonantly produced in pairs via a spin-1 octet, as we show within a renormalizable coloron model. We analyze kinematic distributions of the 3b final state that differentiate between these two production mechanisms, as well as between scalar octets and supersymmetric Higgs bosons. A scalar octet of mass in the 140-150 GeV range can explain the nonstandard shape of the b-jet transverse energy distributions reported by the CDF Collaboration, especially when the coloron mass is slightly above twice the scalar mass. The dominant decay mode of the scalar octet in that case is into a pair of gluons, so that the production of a pair of dijet resonances is large in this model, of about 40 pb at the Tevatron. Even when a W boson is radiated from the initial state, the inclusive cross section for producing a dijet resonance near the scalar octet mass remains sizable, around 0.15 pb.

LHC predictions from a tevatron anomaly in the top quark forward-backward asymmetry

“…For instance, in ref. [39] the axigluon G can decay into two scalar color-octets (if they are lighter than G ), which belong to the other components of the Σ field. The scalar octet may further decay into two jets, so there are then four jets in the final state and the direct dijet searches become much less of a JHEP03(2011)003 constraint.…”

“…For the production of pp → G + W ± , the final state is 2 j + + / E T , which has a smaller background than the dijet resonance channel and thus may have a better discovery reach at the LHC. The partonic production cross section in leading order QCD is calculated to be [39] …”

Minimal SU(3)×SU(3) symmetry breaking patterns

“…The vacuum structure of this theory is useful for various model building applications, including in the contexts of the ReCoM [8,9] and trinification [15][16][17], fermion mass hierarchies [18,19], or chiral symmetry breaking in strongly coupled gauge theories [27]. In addition, it opens new possibilities for nonstandard cosmology, such as color breaking in the early universe followed by color restoration at a lower temperature [28].…”

“…If SUð3Þ × SUð3Þ is a gauge symmetry, the 8 NGBs become the longitudinal degrees of freedom for a heavy spin-1 field transforming as an octet under the unbroken SUð3Þ. The remaining 10 degrees of freedom are massive and can be decomposed into 8 þ 1 þ 1 0 under the unbroken SUð3Þ vacuum symmetry [8]. The heavy octet scalar has a squared mass given in Eq.…”

“…This requires the spontaneous breaking of the product group into its diagonal subgroup. A simple structure that achieves that breaking consists of a single scalar field that transforms in the bifundamental representation, with a potential that includes a trilinear interaction, as discussed in the renormalizable coloron model (ReCoM) [8][9][10]. A model of this type has been recently proposed as a solution to the strong CP problem [11].…”