Unitarity constraints on the stabilized Randall$ndash$Sundrum scenario

Choudhury, Debajyoti; Choudhury, S.; Gupta, Abhinav; Mahajan, Namit

doi:10.1088/0954-3899/28/6/303

Cited by 13 publications

(9 citation statements)

References 32 publications

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“…To find when the perturbative approach breaks, it is customary (see, e.g., [21][22][23]) to study the perturbative unitarity of the scatterings between SM bosons mediated by the radion. The main constraint comes from W bosons scatterings, for which perturbative unitarity is maintained as long as [22] .…”

Section: A the Dfgk Modelmentioning

confidence: 99%

Exact identification of the radion and its coupling to the observable sector

2004

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Braneworld models in extra dimensions can be tested in laboratory by the coupling of the radion to the standard model fields. The identification of the radion as a canonically normalized field involves a careful general relativity treatment: if a bulk scalar is responsible for the stabilization of the system, its fluctuations are entangled with the perturbations of the metric and they also have to be taken into account (similarly to the well-developed theory of scalar metric perturbations in 4D cosmology with a scalar field). Extracting a proper dynamical variable in a warped geometry/scalar setting is a nontrivial task, performed so far only in the limit of negligible backreaction of the scalar field on the background geometry. We perform the general calculation, diagonalizing the action up to second order in the perturbations and identifying the physical eigenmodes of the system for any amplitude of the bulk scalar. This computation allows us to derive a very simple expression for the exact coupling of the eigenmodes to the standard model fields on the brane, valid for an arbitrary background configuration. As an application, we discuss the Goldberger-Wise mechanism for the stabilization of the radion in the Randall-Sundrum-type models. The existing studies, limited to small amplitude of the bulk scalar field, are characterized by a radion mass which is significantly below the physical scale at the observable brane. We extend them beyond the small backreaction regime. For intermediate amplitudes, the radion mass approaches the electroweak scale, while its coupling to the observable brane remains nearly constant. At very high amplitudes, the radion mass instead decreases, while the coupling sharply increases. Severe experimental constraints are expected in this regime.

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Section: A the Dfgk Modelmentioning

confidence: 99%

Exact identification of the radion and its coupling to the observable sector

2004

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“…With the presence of another scalar in the theory with couplings similar to those of the Higgs boson, it becomes important to inquire if it ruins the perturbative unitarity of the theory. In fact, a lot of work has been done in this aspect of the radion [38][39][40][41], and it can be concluded that the contribution of a light radion with Λ φ ∈ ½1∶5 TeV to the amplitudes of these processes are subleading, and hence highenergy behavior is majorly decided by the SM Higgs boson. (ii) Electroweak precision data.-The oblique parameters can be a useful way to constrain the effects of new physics, especially when the energy scale involved is close to m Z=W .…”

Section: Theoretical and Experimental Constraintsmentioning

confidence: 99%

Discussing 125 GeV and 95 GeV excess in light radion model

Sachdeva

Sadhukhan

2020

Phys. Rev. D

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Even if the LHC observations are consistent with the Standard model (SM), current LHC results are not precise enough to rule out the presence of new physics. Taking a contrarian view of the SM Higgs fandom, we look out for a more suitable candidate for the 125 GeV boson observed at the LHC. At the same time, a recent result from CMS hints toward an excess near 95 GeV in the diphoton (γγ) channel. Given these aspects, we revisit the Higgs-radion mixing model to explore the viability of the radion mixed Higgs to be the 125 GeV boson along with the presence of a light radion (to be precise, Higgs mixed radion) that can show up in future experiments in the γγ channel. We find that the mixed radion-Higgs scenario gives a better fit than the SM, with the radion mixed Higgs as a more suitable 125 GeV scalar candidate. It also gives rise to a diphoton excess from the light radion, consistent with the LHC observations.

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“…In fact, a lot of work has been done in this aspect of the radion [34][35][36][37] and it can be concluded that the contribution of a light radion with Λ ϕ ∈ [1 : 5] TeV to the amplitudes of these processes are subleading and hence high energy behaviour is majorly decided by the SM higgs boson.…”

Section: Theoretical and Experimental Constraintsmentioning

confidence: 99%

Discussing 125 GeV and 95 GeV excess in Light Radion Model

Sachdeva,

Sadhukhan

2019

Preprint

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Even if the LHC observations are consistent with the Standard model (SM), current LHC results are not precise enough to rule out the presence of new physics. Taking a contrarian view of the SM Higgs fandom, we look out for a more suitable candidate for the 125 GeV boson observed at the LHC. At the same time, a recent result from CMS hints towards an excess near 95 GeV in the diphoton (γγ) channel. Given these aspects, we revisit the Higgs-radion mixing model to explore the viability of the radion mixed Higgs to be the 125 GeV boson along with the presence of a light radion (to be precise Higgs mixed radion) that can show up in future experiments in the γγ channel. We find that the mixed radion-Higgs scenario gives a better fit than the SM, with the radion mixed Higgs as a more suitable 125 GeV scalar candidate. It also gives rise to a diphoton excess from the light radion, consistent with the LHC observations.

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Unitarity constraints on the stabilized Randall$ndash$Sundrum scenario

Cited by 13 publications

References 32 publications

Exact identification of the radion and its coupling to the observable sector

Exact identification of the radion and its coupling to the observable sector

Discussing 125 GeV and 95 GeV excess in light radion model

Discussing 125 GeV and 95 GeV excess in Light Radion Model

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