Avoiding the Goldstone Boson Catastrophe in general renormalisable field theories at two loops

Braathen, Johannes; Goodsell, Mark D.

doi:10.1007/jhep12(2016)056

Cited by 37 publications

(87 citation statements)

References 62 publications

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“…However, for the latter, we may expect that when we include Goldstone bosons in the MS calculations, we will encounter IR divergences in the limit m G,G ± → 0 even if we include the dependence on external momenta (this is the so-called "Goldstone Boson Catastrophe" [102]), and it will be unavoidable to employ an OS renormalisation scheme for the Goldstone boson masses as was done in Ref. [103] (for other solutions see also [126][127][128][129]).…”

Section: Maximal Possible Size Of the Bsm Correctionsmentioning

confidence: 99%

Leading two-loop corrections to the Higgs boson self-couplings in models with extended scalar sectors

Braathen

Kanemura

2020

Eur. Phys. J. C

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We compute the dominant two-loop corrections to the Higgs trilinear coupling λ hhh and to the Higgs quartic coupling λ hhhh in models with extended Higgs sectors, using the effective-potential approximation.We provide in this paper all necessary details about our calculations, and present general MS expressions for derivatives of the integrals appearing in the effective potential at two loops. We also consider three particular Beyond-the-Standard-Model (BSM) scenarios -namely a typical scenario of an Inert Doublet Model (IDM), and scenarios of a Two-Higgs-Doublet Model (2HDM) and of a Higgs Singlet Model (HSM) without scalar mixing -and we include all the necessary finite counterterms to obtain (in addition to MS results) on-shell scheme expressions for the corrections to the Higgs self-couplings. With these analytic results, we investigate the possible magnitude of two-loop BSM contributions to the Higgs self-couplings and the fate of the non-decoupling effects that are known to appear at one loop. We find that, at least as long as pertubative unitarity conditions are fulfilled, the size of two-loop corrections remains well below that of one-loop corrections. Typically, two-loop contributions to λ hhh amount to approximately 20% of those at one loop, implying that the non-decoupling effects observed at one loop are not significantly modified, but also meaning that higher-order corrections need to be taken into account for the future perspective of precise measurements of the Higgs trilinear coupling.

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Section: Maximal Possible Size Of the Bsm Correctionsmentioning

confidence: 99%

Leading two-loop corrections to the Higgs boson self-couplings in models with extended scalar sectors

Braathen

Kanemura

2020

Eur. Phys. J. C

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“…SPheno calculates by default the mass spectrum at the full one-loop level and includes all important two-loop corrections to the neutral scalar masses [34,48,49]. Special care is needed at the two-loop level to avoid the so-called Goldstone boson catastrophe [50]. In addition, SPheno calculates all decay modes of the particles at tree-and one-loop-level [51], including the modes discussed recently in Ref.…”

Section: Numerical Setupmentioning

confidence: 99%

Perturbativity constraints in BSM models

Krauss¹,

Staub

2018

Eur. Phys. J. C

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Phenomenological studies performed for nonsupersymmetric extensions of the Standard Model usually use tree-level parameters as input to define the scalar sector of the model. This implicitly assumes that a full on-shell calculation of the scalar sector is possible -and meaningful. However, this doesn't have to be the case as we show explicitly at the example of the Georgi-Machacek model. This model comes with an appealing custodial symmetry to explain the smallness of the ρ parameter. However, the model cannot be renormalised on-shell without breaking the custodial symmetry. Moreover, we find that it can often happen that the radiative corrections are so large that any consideration based on a perturbative expansion appears to be meaningless: counter-terms to quartic couplings can become much larger than 4π and/or two-loop mass corrections can become larger than the one-loop ones. Therefore, conditions are necessary to single out parameter regions which cannot be treated perturbatively. We propose and discuss different sets of such perturbativity conditions and show their impact on the parameter space of the Georgi-Machacek model. Moreover, the proposed conditions are general enough that they can be applied to other models as well. We also point out that the vacuum stability constraints in the Georgi-Machacek model, which have so far only been applied at the tree level, receive crucial radiative corrections. We show that large regions of the parameter space which feature a stable electroweak vacuum at the loop level would have been -wrongly -ruled out by the tree-level conditions.

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“…(2.32) of Ref. [127] to find the derivative of the (effective) potential V with respect to the scalars:…”

Section: Appendix C: Infrared Divergent Parts Of Passarinoveltman Intmentioning

confidence: 99%

Generic calculation of two-body partial decay widths at the full one-loop level

2017

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We describe a fully generic implementation of two-body partial decay widths at the full one-loop level in the SARAH and SPheno framework compatible with most supported models. It incorporates fermionic decays to a fermion and a scalar or a gauge boson as well as scalar decays into two fermions, two gauge bosons, two scalars or a scalar and a gauge boson. We present the relevant generic expressions for virtual and real corrections. Whereas wave-function corrections are determined from on-shell conditions, the parameters of the underlying model are by default renormalised in a DR (or MS) scheme. However, the user can also define model-specific counter-terms. As an example we discuss the renormalisation of the electric charge in the Thomson limit for top-quark decays in the standard model. One-loopinduced decays are also supported. The framework additionally allows the addition of mass and mixing corrections induced at higher orders for the involved external states. We explain our procedure to cancel infrared divergences for such cases, which is achieved through an infrared counter-term taking into account corrected Goldstone boson vertices. We compare our results for sfermion, gluino and Higgs decays in the minimal supersymmetric standard model (MSSM) against the public codes SFOLD, FVSFOLD and HFOLD and explain observed differences. Radiatively induced gluino and neutralino decays are compared against the original implementation in SPheno in the MSSM. We exactly reproduce the results of the code CNNDecays for decays of neutralinos and charginos in R-parity violating models. The new version SARAH 4.11.0 by default includes the calculation of a

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Avoiding the Goldstone Boson Catastrophe in general renormalisable field theories at two loops

Cited by 37 publications

References 62 publications

Leading two-loop corrections to the Higgs boson self-couplings in models with extended scalar sectors

Leading two-loop corrections to the Higgs boson self-couplings in models with extended scalar sectors

Perturbativity constraints in BSM models

Generic calculation of two-body partial decay widths at the full one-loop level

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