Probing colored particles with photons, leptons, and jets

Abstract

If pairs of new colored particles are produced at the Large Hadron Collider, determining their quantum numbers, and even discovering them, can be non-trivial. We suggest that valuable information can be obtained by measuring the resonant signals of their near-threshold QCD bound states. If the particles are charged, the resulting signatures include photons and leptons and are sufficiently rich for unambiguously determining their various quantum numbers, including the charge, color representation and spin, and obtaining a precise mass measurement. These signals provide well-motivated benchmark models for resonance searches in the dijet, photon+jet, diphoton and dilepton channels. While these measurements require that the lifetime of the new particles be not too short, the resulting limits, unlike those from direct searches for pair production above threshold, do not depend on the particles' decay modes. These limits may be competitive with more direct searches if the particles decay in an obscure way.

Exotic colored scalars at the LHC

“…2) applies in all cases of dominant three body final state. We conclude that the search for bound states is truly a generic tool to look for exotic colored scalars [4]. The quantum numbers of X determine the gluon fusion (ggF) production cross section of S as well as its decay rates into pairs of vector bosons: gg, γγ, ZZ, Zγ and W W .…”

“…For example, as demonstrated by the non-degenerate quartet scenario (case B in section 5), the data still allow four colored states with m X 250 GeV. In this section we study another way to discover light colored scalars, which might go first through the observation of their QCD bound state [4,5,68]. Moreover, constraints derived from bound state searches are less model dependent, in the sense that they do not depend on the decay mode of X.…”

“…For exotic states the consequent constraints are often less model dependent than continuum pair production searches (see e.g. [4,5]). …”

Probing light stops with stoponium

“…Our analysis relies on a number of previous works [41][42][43][44][45][46][47][48][49][50], notably those of Martin and collaborators [51][52][53][54]. Next we describe in more detail the basic requirements for observable stoponium annihilation decays.…”

Natural supersymmetry in warped space

“…This removes LHC constraints on the stop mass (see e.g. [61]), reducing the tension between LHC results and naturalness. Nonetheless, our model is also viable with R-parity conservation.…”