Data driven search in the displaced $ b\overline{b} $ pair channel for a Higgs boson decaying to long-lived neutral particles

131

182

Solutions to the hierarchy problem usually require top partners. In standard SUSY or composite Higgs theories, the partners carry SM color and are becoming increasingly constrained by LHC searches. However, theories like Folded SUSY (FS), Twin Higgs (TH) and Quirky Little Higgs (QLH) introduce uncolored top partners, which can be SM singlets or carry electroweak charge. Their small production cross section left doubt as to whether the LHC can effectively probe such scenarios. Typically, these partners are charged under their own mirror color gauge group. In FS and QLH, the absence of light mirror matter allows glueballs to form at the bottom of the mirror spectrum. This is also the case in some TH realizations. The Higgs can decay to these mirror glueballs, with the glueballs decaying into SM particles with potentially observable lifetimes. We undertake the first detailed study of this glueball signature and quantitatively demonstrate the discovery potential of uncolored naturalness via exotic Higgs decays at the LHC and a potential future 100 TeV collider. Our findings indicate that mirror glueballs are the smoking gun signature of natural FS and QLH type theories, in analogy to tree-level Higgs coupling shifts for the TH. We show that glueball masses in the ∼ 10-60 GeV mass range are theoretically preferred. Careful treatment of lifetime, mirror-hadronization and nonperturbative uncertainties is required to perform meaningful collider studies. We outline several new search strategies for exotic Higgs decays of the form h → XX → 4f at the LHC, with X having lifetimes in the 10µm to km range. We find that FS stops can be probed with masses up to 600 (1100) GeV at the LHC with 300 (3000) fb −1 of data, and TH top partners could be accessible with masses up to 900 (1500) GeV. This makes exotic Higgs decays the prime discovery channel for uncolored naturalness at the LHC.

Section: Higgs Portal Observablesmentioning

confidence: 99%

Discovering uncolored naturalness in exotic Higgs decays

Curtin

Verhaaren

2015

131

182

“…To confirm the zero-background hypothesis, we review the major sources of fake displaced vertices [46,81].…”

Section: Appendix: Estimate Of 2 DV Background For Dijet Searchmentioning

confidence: 99%

“…Assuming that the reconstruction of background DVs are uncorrelated [81], we require 2DVs in the event instead while keeping the same DV selection cuts for each of the DV, finding σ 2DV ∼ σ 1DV ξ DV ∼ 3 × 10 −10 fb for Run I data. In subsequent runs, the multijet rate is larger, and pileup contributions to accidental crossings is also more significant; each of these effects is an O(1 − 10) factor.…”

Section: Appendix: Estimate Of 2 DV Background For Dijet Searchmentioning

confidence: 99%

Probing baryogenesis with displaced vertices at the LHC

Cui

Shuve

2015

102

124

The generation of the asymmetric cosmic baryon abundance requires a departure from thermal equilibrium in the early universe. In a large class of baryogenesis models, the baryon asymmetry results from the out-of-equilibrium decay of a new, massive particle. We highlight that in the interesting scenario where this particle has a weak scale mass, this out-of-equilibrium condition requires a proper decay length larger than O(1) mm. Such new fields are within reach of the LHC, at which they can be pair produced leaving a distinctive, displaced-vertex signature. This scenario is realized in the recently proposed mechanism of baryogenesis where the baryon asymmetry is produced through the freeze-out and subsequent decay of a meta-stable weakly interacting massive particle ("WIMP baryogenesis"). In analogy to missing energy searches for WIMP dark matter, the LHC is an excellent probe of these new long-lived particles responsible for baryogenesis via the low-background displaced vertex channel. In our paper, we estimate the limits on simplified models inspired by WIMP baryogenesis from two of the most sensitive collider searches by CMS and ATLAS with 8 TeV LHC data. We also estimate the LHC reach at 13 TeV using current strategies, and demonstrate that up to a factor of 100 improvement in cross-section limits can be achieved by requiring two displaced vertices while lowering kinematic thresholds. For meta-stable WIMPs produced through electroweak interactions, the high luminosity LHC is sensitive to masses up to 2.5 TeV for lifetimes around 1 cm, while for singlets pair-produced through the off-shell-Higgs portal, the LHC is sensitive to production cross sections of O(10) ab for benchmark masses around 150 GeV. Our analysis and proposals also generally apply to displaced vertex signatures from other new physics such as hidden valley models, twin Higgs models and displaced supersymmetry.

“…The Higgs can also decay to two light scalars, h 1 → h 2 h 2 , where h 2 decays to bb pairs. These decay chains can then be searched for using associated hZ or hW production with four b-tagged jets in the final state (possibly originating from two displaced secondary vertices, see also [70]) combining to the Higgs mass. As discussed above, the h 1 → h 2 h 2 branching ratio can be sizeable, of O(20%).…”

Section: Sm + Dm With Extra Scalar Singletmentioning

confidence: 99%

Constraining Higgs mediated dark matter interactions

Greljo

Julio

Kamenik

et al. 2013

Abstract:We perform an analysis of Higgs portal models of dark matter (DM), where DM is light enough to contribute to invisible Higgs decays. Using effective field theory we show that DM can be a thermal relic only if there are additional light particles present with masses below a few 100 GeV. We give three concrete examples of viable Higgs portal models of light DM: (i) the SM extended by DM scalar along with an electroweak triplet and a singlet, (ii) a Two Higgs Doublet Model of type II with additional scalar DM, (iii) SM with DM and an extra scalar singlet that is lighter than DM. In all three examples the B(h → invisible) constraint is not too restrictive, because it is governed by different parameters than the relic abundance. Additional light particles can have implications for flavor violation and collider searches.