Higgs interference effects at the one-loop level in the 1-Higgs-Singlet extension of the Standard Model

Kauer, N.; Lind, Alexander; Maierhöfer, Philipp; Song, W. M.

doi:10.1007/jhep07(2019)108

Cited by 7 publications

(2 citation statements)

References 101 publications

(126 reference statements)

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“…In the SM, for heavy Higgs bosons, it is known that the Higgs signal (with a large QCD K factor [66,67]) has sizeable interference effects with the QCD continuum in gg → t t [68][69][70]. This influences exclusion constraints, but is also a viable source for new physics beyond the SM [20,[71][72][73][74][75][76][77][78][79][80]. The predominant focus of previous work was therefore devoted to isolating the resonance shape and cross section, which is not our focus here.…”

Section: A Simplified Model and Its Eft Limitmentioning

confidence: 99%

Effective field theory and scalar extensions of the top quark sector

2020

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Effective field theory (EFT) approaches are widely used at the LHC, such that it is important to study their validity, and ease of matching to specific new physics models. In this paper, we consider a generic extension of the SM in which a top quark couples to a new heavy scalar. We find the dimension six operators generated by this theory at low energy, and match the EFT to the full theory up to NLO precision in the simplified model coupling. We then examine the range of validity of the EFT description in top pair production, finding excellent validity even if the scalar mass is only slightly above LHC energies, provided NLO corrections are included. In the absence of the latter, the LO EFT overestimates kinematic distributions, such that over-optimistic constraints on BSM contributions are obtained. We next examine the constraints on the EFT and full models that are expected to be obtained from both top pair and four top production at the LHC, finding for low scalar masses that both processes show similar exclusion power. However, for larger masses, estimated LHC uncertainties push constraints into the non-perturbative regime, where the full model is difficult to analyse, and thus not perturbatively matchable to the EFT. This highlights the necessity to improve uncertainties of SM hypotheses in top final states.

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Section: A Simplified Model and Its Eft Limitmentioning

confidence: 99%

Effective field theory and scalar extensions of the top quark sector

2020

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“…Other aspects of resonance-continuum interferences as a probe of new physics at the LHC, with approaches similar or complementary to the present paper, have been given in Refs. [94][95][96][97][98][99][100]. Also, Ref.…”

Section: Introductionmentioning

confidence: 99%

Signal-background interference for digluon resonances at the Large Hadron Collider

Bhattiprolu

Martin

2020

Phys. Rev. D

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We study the interference between the amplitudes for gg → X → gg, where X is a new heavy digluon resonance, and the QCD background gg → gg, at the Large Hadron Collider. The interference produces a large low-mass tail and a deficit of events above the resonance mass, compared to the naive pure-resonance peak. For a variety of different resonance quantum numbers and masses, we evaluate the signal-background interference contribution at leading order, including showering, hadronization, and detector effects. The resulting new physics dijet mass distribution may have a shape that appears, after QCD background fitting and subtraction, to resemble an enhanced peak, a shelf, a peak/dip, or even a pure dip. We argue that the true limits on new digluon resonances are likely to differ significantly from the limits obtained when interference is neglected, especially if the branching ratio to gg is less than 1.

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Higgs interference effects in top-quark pair production in the 1HSM

Banfi,

Kauer,

Lind

et al. 2024

J. High Energ. Phys.

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We present a next-to-leading-order (NLO) study of the process pp (→ {h1, h2}) →$$ t\overline{t} $$ t t ¯ + X in the 1-Higgs-singlet extension of the Standard Model with an additional heavy Higgs boson h2 that mixes with the light Higgs boson h1. This process is subject to large interference effects between loop-induced Higgs-mediated amplitudes and the QCD continuum background which tend to overcompensate any resonance contributions. A reliable modelling of the resulting top-pair invariant mass shapes requires the inclusion of higher-order QCD corrections, which are presented here. The computation of these NLO corrections is exact in all contributions but in the class of non-factorisable two-loop diagrams which are included in an approximate way such that all infrared singular limits are preserved. We present numerical results for several benchmark points with heavy Higgs masses in the range 700–3000 GeV considering the production of stable top quarks. We find that the interference effects dominate the BSM signal yielding sharp dip structures instead of resonance peaks. The significance and excludability of the BSM effect is explored for the LHC Run 2, Run 3 and HL-LHC.

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Higgs interference effects at the one-loop level in the 1-Higgs-Singlet extension of the Standard Model

Cited by 7 publications

References 101 publications

Effective field theory and scalar extensions of the top quark sector

Effective field theory and scalar extensions of the top quark sector

Signal-background interference for digluon resonances at the Large Hadron Collider

Higgs interference effects in top-quark pair production in the 1HSM

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