Long-lived, colour-triplet scalars from unnaturalness

James Barnard, Peter Cox, Tony Gherghetta, Andrew Spray

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Abstract: Long-lived, colour-triplet scalars are a generic prediction of unnatural, or split, composite Higgs models where the spontaneous global-symmetry breaking scale f ≳ 10 TeV and an unbroken SU(5) symmetry is preserved. Since the triplet scalars are pseudo NambuGoldstone bosons they are split from the much heavier composite-sector resonances and are the lightest exotic, coloured states. This makes them ideal to search for at colliders. Due to discrete symmetries the triplet scalar decays via a dimension-six term and given the large suppression scale f is often metastable. We show that existing searches for collider-stable R-hadrons from Run-I at the LHC forbid a triplet scalar mass below 845 GeV, whereas with 300 fb−1 at 13 TeV triplet scalar masses up to 1.4 TeV can be discovered. For shorter lifetimes displaced-vertex searches provide a discovery reach of up to 1.8 TeV. In addition we present exclusion and discovery reaches of future hadron colliders as well as indirect limits that arise from modifications of the Higgs couplings.

Original languageEnglish (US)
Article number3
JournalJournal of High Energy Physics
Issue number3
StatePublished - Mar 1 2016

Bibliographical note

Funding Information:
We thank C.-P. Yuan for useful discussions as well as Abi Soffer and Nimrod Taiblum for helpful correspondence regarding ref. [29]. This work was supported by the Australian Research Council. TG was supported by the Department of Energy grant DE-SC0011842. AS was also supported by IBS under the project code IBS-R018-D1. PC is grateful to the Fine Theoretical Physics Institute for hospitality during the completion of this work.

Publisher Copyright:
© 2016, The Author(s).


  • Beyond Standard Model
  • Technicolor and Composite Models


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