Distinguishing a Higgs-like dilaton scenario with a complete bosonic effective field theory basis

Hernández-León, Patricia; Merlo, Luca

doi:10.1103/physrevd.96.075008

Cited by 30 publications

(19 citation statements)

References 187 publications

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“…The other common non-trivial features of near-conformal gauge theories are the emergence of a light scalar resonance. Such a new degree of freedom at low energy may be identified as a dilaton arising from the spontaneous breaking of scale symmetry, and can be used to extend the Higgs sector of the standard model of particle physics [31][32][33][34][35][36][37][38][39][40][41]. Interestingly, recent lattice studies of SU (3) gauge theories with 8 fundamental Dirac fermions [42][43][44][45], as well as 2 two-index symmetric Dirac fermions [46][47][48][49][50], performed with moderate sizes of the fermion mass found a relatively light scalar in the spectrum.…”

Section: Introductionmentioning

confidence: 99%

Into the conformal window: Multirepresentation gauge theories

2020

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We investigate the conformal window of four-dimensional gauge theories with fermionic matter fields in multiple representations. Of particularly relevant examples are the ultra-violet complete models with fermions in two distinct representations considered in the context of composite Higgs and top partial-compositeness. We first discuss various analytical approaches to unveil the lower edge of the conformal window and their extension to the multiple matter representations. In particular, we argue that the scheme-independent series expansion for the anomalous dimension of a fermion bilinear at an infrared fixed point, γχ χ, IR , combined with the conjectured critical condition, γχ χ, IR = 1 or equivalently γχ χ, IR (2−γχ χ, IR ) = 1, can be used to determine the boundary of conformal phase transition on fully physical grounds. In illustrative cases of SU (2) and SU (3) theories with N R Dirac fermions in various representations, we assess our results by comparing to other analytical or lattice results. *

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Section: Introductionmentioning

confidence: 99%

Into the conformal window: Multirepresentation gauge theories

2020

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“…An alternative would be to considered a non-linear realisation and the corresponding effective Lagrangian dubbed HEFT [181][182][183][184][185][186]. In this context, however, a much larger number of operators should be taken into consideration and a slightly different phenomenology is expected [187][188][189][190][191][192][193][194][195][196]. The focus in this paper is on the linear EWSB realisation and therefore the HEFT Lagrangian will not be considered in what follows.…”

Section: (34)mentioning

confidence: 99%

Revisiting Minimal Lepton Flavour Violation in the light of leptonic CP violation

Dinh

Merlo

Petcov

et al. 2017

J. High Energ. Phys.

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The Minimal Lepton Flavour Violation (MLFV) framework is discussed after the recent indication for CP violation in the leptonic sector. Among the three distinct versions of MLFV, the one with degenerate right-handed neutrinos will be disfavoured, if this indication is confirmed. The predictions for leptonic radiative rare decays and muon conversion in nuclei are analysed, identifying strategies to disentangle the different MLFV scenarios. The claim that the present anomalies in the semi-leptonic B-meson decays can be explained within the MLFV context is critically re-examined concluding that such an explanation is not compatible with the present bounds from purely leptonic processes.

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“…In order to reproduce the expected value of the EW VEV, v ≡ 245 GeV fixed through the W gauge boson mass, it is then necessary to invoke a large value of the Higgs quartic coupling λ, describing in this way a strongly interacting scenario with a non-linearly realised EWSB mechanism. This is an intriguing possibility, especially considering the recent interest in non-SM descriptions of the Higgs sector, such as composite Higgs models [87][88][89][90][91][92][93][94][95], dilaton models [96][97][98][99][100][101][102][103], or general effective Lagrangians [104][105][106][107][108][109][110][111][112][113][114][115][116][117][118][119][120][121]. In this letter, however, the traditional EWSB mechanism will be considered, and this requires to invoke a fine tuning: either there is cancellation between µ 2 and λ HΦ v 2 Φ , or λ HΦ is artificially small.…”

Section: Jhep10(2017)168mentioning

confidence: 99%

The minimal flavour violating axion

Arias-Aragón

Merlo

2017

J. High Energ. Phys.

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The solution to the Strong CP problem is analysed within the Minimal Flavour Violation (MFV) context. An Abelian factor of the complete flavour symmetry of the fermionic kinetic terms may play the role of the Peccei-Quinn symmetry in traditional axion models. Its spontaneous breaking, due to the addition of a complex scalar field to the Standard Model scalar spectrum, generates the MFV axion, which may redefine away the QCD theta parameter. It differs from the traditional QCD axion for its couplings that are governed by the fermion charges under the axial Abelian symmetry. It is also distinct from the so-called Axiflavon, as the MFV axion does not describe flavour violation, while it does induce flavour non-universality effects. The MFV axion phenomenology is discussed considering astrophysical, collider and flavour data.

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Distinguishing a Higgs-like dilaton scenario with a complete bosonic effective field theory basis

Cited by 30 publications

References 187 publications

Into the conformal window: Multirepresentation gauge theories

Into the conformal window: Multirepresentation gauge theories

Revisiting Minimal Lepton Flavour Violation in the light of leptonic CP violation

The minimal flavour violating axion

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