Leptons and photons at the LHC: cascades through spinless adjoints

Abstract

Abstract:We study the hadron collider phenomenology of (1,0) Kaluza-Klein modes along two universal extra dimensions compactified on the chiral square. Cascade decays of spinless adjoints proceed through tree-level 3-body decays involving leptons as well as one-loop 2-body decays involving photons. As a result, spectacular events with as many as six charged leptons, or one photon plus four charged leptons are expected to be observed at the LHC. Unusual events with relatively large branching fractions include three leptons of same charge plus one lepton of opposite charge, or one photon plus two leptons of same charge. We estimate the current limit from the Tevatron on the compactification scale, set by searches for trilepton events, to be around 270 GeV.

Colored resonant signals at the LHC: largest rate and simplest topology

“…Sextet fermions, the so-called "quixes", associated with chiral color [11] and top quark condensate models [12] may also be produced via quark-gluon annihilation. Color-octet scalars that are SU(2) L singlets can arise in technicolor models [13], and in universal extra dimensions [14,15]. Color-octet vectors have been extensively explored as axigluons [11,16] and colorons [17][18][19].…”

Constraints on heavy colored scalars from Tevatron’s Higgs exclusion limit

“…The free parameters which govern the scalar properties are m S , λ 1 , and G 4S . We note that higher-order operators that break the S → −S symmetry present in the Lagrangians above, and which allow the scalar to decay, can be obtained in explicit models [6,7]. We neglect them here since we anticipate that they have little effect on the gg → h production cross section.…”

The SM extension with color-octet scalars: diphoton enhancement and global fit of LHC Higgs data

“…It should be emphasized that the color-octet scalars are well motivated in many basic theories, such as various SUSY constructions [30], topcolor models [31] and the models with extra dimensions [32]. Meanwhile, their phenomenology has been studied comprehensively.…”