Z-peaked excess from heavy gluon decays to vector-like quarks

Abstract

A 3 sigma excess has been recently announced by ATLAS in events with Z-peaked dilepton pairs, jets, and large transverse missing energy. We interpret this finding in the context of composite Higgs / RS theories. We find that composite Higgs theories with custodial symmetry protection to the $Zb\bar{b}$ coupling predict a significant contribution to $ZZbb$ (and to $hhbb$) final states coming from heavy gluon decays to pairs of bottom-partner vector-like quarks. The heavy gluon to vector-like quarks signal is largely accepted by the ATLAS selection if one of the $Z$ boson in the $ZZbb$ final state decays leptonically and the other to neutrinos. For a bottom partner of $\sim$900 GeV, we find that the ATLAS excess can be reproduced by composite Higgs models, in an experimentally allowed parameter space, for heavy gluon masses roughly in a range 1.87 - 2.15 TeV and for heavy gluon couplings to light quarks within $\sim (0.3-0.65)g_S$. We briefly discuss the implication of this result for future experimental tests.

23 pp. v2: minor changes, references added

References in corpus (12)

• PYTHIA 6.4 Physics and Manual
• Implications of CTEQ global analysis for collider observables
• FeynRules - Feynman rules made easy
• A custodial symmetry for Zbb
• Search for resonances and quantum black holes using dijet mass spectra in proton-proton collisions at sqrt(s) = 8 TeV
• Heavy Quarks Above the Top at the Tevatron
• Search for physics beyond the standard model in events with two leptons, jets, and missing transverse momentum in pp collisions at sqrt(s) = 8 TeV
• Early discovery of top partners and test of the Higgs nature
• $\Delta F=1$ constraints on composite Higgs models with LR parity
• New W-prime signals at the LHC
• The Elusive Gluon
• Consistency of the recent ATLAS $Z+E_T^{\mathrm{miss}}$ excess in a simplified GGM model

Cited by in corpus (6)

• Probing Charged Higgs Bosons in the 2-Higgs Doublet Model Type-II with Vector-Like Quarks
• Anatomy of Vector-Like Bottom-Quark Models in the Alignment Limit of the 2-Higgs Doublet Model Type-II
• Leptophobic boson signals with leptons, jets and missing energy
• Search for charged Higgs bosons through vector-like top quark pair production at the LHC
• Explanation of the ATLAS Z-peaked excess in the NMSSM
• Aspects of astrophysical particle production and beyond the Standard Model phenomenology