The leptonic future of the Higgs

115

The Universal One-Loop Effective Action (UOLEA) is a general expression for the effective action obtained by evaluating in a model-independent way the one-loop expansion of a functional path integral. It can be used to match UV theories to their low-energy EFTs more efficiently by avoiding redundant steps in the application of functional methods, simplifying the process of obtaining Wilson coefficients of operators up to dimension six. In addition to loops involving only heavy fields, matching may require the inclusion of loops containing both heavy and light particles. Here we use the recentlydeveloped covariant diagram technique to extend the UOLEA to include heavy-light terms which retain the same universal structure as the previously-derived heavy-only terms. As an example of its application, we integrate out a heavy singlet scalar with a linear coupling to a light doublet Higgs. The extension presented here is a first step towards completing the UOLEA to incorporate all possible structures encountered in a covariant derivative expansion of the one-loop path integral.

Section: Jhep08(2017)054mentioning

confidence: 99%

Extending the Universal One-Loop Effective Action: heavy-light coefficients

Ellis

Quevillon

You

et al. 2017

115

“…[22,37,100,101,104], future lepton colliders are expected to be sensitive to δ Zh ∼ 0.5% or better. For sin θ = 0.01, 0.05, the corresponding parameter space lies outside of the solid red contours in figures 10-11, using eq.…”

Section: Additional Probesmentioning

confidence: 99%

Non-resonant collider signatures of a singlet-driven electroweak phase transition

Chen

Kozaczuk

Lewis

2017

107

Abstract:We analyze the collider signatures of the real singlet extension of the Standard Model in regions consistent with a strong first-order electroweak phase transition and a singlet-like scalar heavier than the Standard Model-like Higgs. A definitive correlation exists between the strength of the phase transition and the trilinear coupling of the Higgs to two singlet-like scalars, and hence between the phase transition and non-resonant scalar pair production involving the singlet at colliders. We study the prospects for observing these processes at the LHC and a future 100 TeV pp collider, focusing particularly on double singlet production. We also discuss correlations between the strength of the electroweak phase transition and other observables at hadron and future lepton colliders. Searches for non-resonant singlet-like scalar pair production at 100 TeV would provide a sensitive probe of the electroweak phase transition in this model, complementing resonant di-Higgs searches and precision measurements. Our study illustrates a strategy for systematically exploring the phenomenologically viable parameter space of this model, which we hope will be useful for future work.

“…[48] for a recent overview). Parametrically similar deviations affect other SM couplings, such as htt, hgg/hγγ and Ztt, which however will be tested with less accuracy than hV V .…”

Section: Jhep11(2017)094mentioning

confidence: 99%

Charged composite scalar dark matter

Balkin

Ruhdorfer

Salvioni

et al. 2017

Abstract:We consider a composite model where both the Higgs and a complex scalar χ, which is the dark matter (DM) candidate, arise as light pseudo Nambu-Goldstone bosons (pNGBs) from a strongly coupled sector with TeV scale confinement. The global symmetry structure is SO(7)/SO(6), and the DM is charged under an exact U(1) DM ⊂ SO(6) that ensures its stability. Depending on whether the χ shift symmetry is respected or broken by the coupling of the top quark to the strong sector, the DM can be much lighter than the Higgs or have a weak-scale mass. Here we focus primarily on the latter possibility. We introduce the lowest-lying composite resonances and impose calculability of the scalar potential via generalized Weinberg sum rules. Compared to previous analyses of pNGB DM, the computation of the relic density is improved by fully accounting for the effects of the fermionic top partners. This plays a crucial role in relaxing the tension with the current DM direct detection constraints. The spectrum of resonances contains exotic top partners charged under the U(1) DM , whose LHC phenomenology is analyzed. We identify a region of parameters with f = 1.4 TeV and 200 GeV m χ 400 GeV that satisfies all existing bounds. This DM candidate will be tested by XENON1T in the near future.