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

The Higgs trilinear coupling λ hhh is of great importance to understand the structure of the Higgs sector and allows searching for indirect signs of Beyond-the-Standard-Model (BSM) physics, even if new states are somehow hidden. In particular, in models with extended Higgs sectors, it is known that non-decouplings effects in BSM-scalar contributions at one loop can cause λ hhh to deviate significantly from its SM prediction, raising the question of what happens at two loops. We review here our calculation [1, 2] of the leading two-loop corrections to λ hhh in an aligned scenario of a Two-Higgs-Doublet Model. We find their typical size to be 10-20% of the one-loop corrections, meaning that they do not modify significantly the one-loop non-decoupling effects, but are not entirely negligible either. I. INTRODUCTIONThe discovery of the 125-GeV Higgs boson at the CERN LHC in 2012 has been a great success for particle physics, and has completed the particle spectrum of the Standard Model (SM). However, while it is now established that the Higgs sector is responsible for the electroweak symmetry breaking (EWSB), very little is known about the nature of the Higgs potential -in fact, only its minimum and the curvature around the minimum are known. Moreover, although some new physics must exist -possibly not too far from the electroweak (EW) scale -to address shortcomings of the SM, there is so far no clear sign of it in experiments. A first possible explanation for this could be that new physics only exists beyond the scale currently accessible at colliders, and hence their effects would be (almost) impossible to find. Another interesting possibility would be that the new states are made somehow difficult to observe via some symmetry or mechanism.A prime example of the latter is alignment [3], which is defined for models of several Higgs doublets as the limit in which the total EW vacuum expectation value (VEV) is colinear in field a Speaker.

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“…Analytic expressions forˆℎ ℎℎ in the SM and the considered BSM theories can be found in Refs. [9,10].…”

Section: Numerical Resultsmentioning

confidence: 99%

On two-loop corrections to the Higgs trilinear coupling in models with extended scalar sectors

Braathen

Kanemura

2019

Physics Letters B

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“…There have been many studies in the literature on the implications of the Higgs precision measurements at current and future colliders on the 2HDMs [39][40][41][42][43][44][45][46][47]. In recent works [48][49][50][51][52][53], we examined the achievable sensitivity of the Higgs and Z factories to probe the virtual effects of the two Higgs doublet model (2HDM) of Type-II and Type-I. With multivariable χ 2 -fit, we found interesting results in setting significant bounds in a large theory parameter space beyond the reach of the high luminosity upgrade of the LHC (HL-LHC).…”

Section: Jhep01(2021)045mentioning

confidence: 99%

Comparative studies of 2HDMs under the Higgs boson precision measurements

Han

et al. 2021

J. High Energ. Phys.

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We perform comparative studies for four types of the two Higgs Doublet Models (2HDMs) under the precision measurements of the Standard Model (SM) Higgs observables at the proposed Higgs factories. We explore the discovery potential based on the hypothetical deviations in the precision data for the 2HDMs up to one-loop level. We find 5σ observability from the χ2 fitting in a significant theory parameter space at future Higgs factories. For the Type-I 2HDM, regions with cos(β − α) ≲ −0.1 or cos(β − α) ≳ 0.08 are discoverable at more than 5σ level. For the other three types of 2HDMs, the 5σ region is even bigger: | cos(β − α)| ≳ 0.02 for tan β ∼ 1. At small and large values of tan β, the region in cos(β − α) is further tightened. We examine the extent to which the different 2HDM theories may be distinguishable from one to the other at the 95% Confidence Level with four benchmark points as case studies. We show that a large part of the parameter space of the other types of 2HDMs can be distinguished from the benchmark points of the target model. The impacts of loop corrections are found to be significant in certain parameter regions.

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“…There are notable predictions in part of scenarios, where the first order phase transition is realized by the non-decoupling loop effect. Such a non-decoupling effect introduced to realize the strongly first order phase transition can also affect various Higgs observables such as the di-photon decay [28][29][30] of the Higgs boson and the triple Higgs boson coupling [31][32][33][34]. This important features can be tested at future collider experiments such as the high-luminosity upgrade of the LHC (HL-LHC) [35] and the International Linear Collider (ILC) [36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Testing aligned CP-violating Higgs sector at future lepton colliders

Kanemura

Kubota

Yagyu

2021

J. High Energ. Phys.

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We discuss the testability of CP-violating phases at future lepton colliders for the scenario which satisfies electric dipole moment data by destructive interferences among several phases. We consider the general but aligned two Higgs doublet model which has the CP-violating phases in the Higgs potential and the Yukawa interaction. The Yukawa interaction terms are aligned to avoid flavor changing neutral currents at tree level. The Higgs potential is also aligned such that the coupling constants of the lightest Higgs boson with the mass of 125 GeV to the Standard Model (SM) particles are the same as those of the SM at tree level. We investigate the azimuthal angle distribution of the hadronic decay of tau leptons arising from production and decay of the extra Higgs bosons, which contains information of the CP-violating phases. From the signal and background simulation, we find that the scenario with finite CP-violating phases can be distinguished from CP conserving one at future lepton colliders like the International Linear Collider.

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

Cited by 40 publications

References 152 publications

On two-loop corrections to the Higgs trilinear coupling in models with extended scalar sectors

On two-loop corrections to the Higgs trilinear coupling in models with extended scalar sectors

Comparative studies of 2HDMs under the Higgs boson precision measurements

Testing aligned CP-violating Higgs sector at future lepton colliders

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