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Amine Ahriche

Publications and source records attributed to Amine Ahriche.

At least 19 recordsLinked to original sources

The Scotogenic Model with Two Inert Doublets: Parameters Space and Electroweak Precision Tests

In this work, we study a scotogenic extension of the Standard Model featuring two inert scalar doublets and three singlet Majorana fermions, where neutrino masses are generated radiatively at one loop. The lightest among the Majorana fermions and neutral scalars can serve as dark matter candidates. We explore the parameter space, considering theoretical constraints (perturbativity, unitarity, vacuum stability) and experimental limits (lepton flavor violation, Higgs measurements, electroweak precision observables). Our analysis identifies regions where sizable Yukawa couplings naturally arise due to constructive interference in the scalar sector. Additionally, we estimate the oblique parameters, finding that only $ΔT$ is sensitive to charged mass splittings, while $ΔS$ and $ΔU$ remain small across the viable parameter space. However, 60\% of the viable parameter space is excluded by the recent CMS measurement of the $W$ boson mass, since the shift $ΔM_W$ depends on the oblique parameters, particularly $ΔT$ that is sensitive to scalar mass splittings.

hep-ph

Novel and Updated Bounds on Flavor-violating Z Interactions in the Lepton Sector

We investigate the experimental bounds on the Flavor-Violating (FV) couplings of the $Z$ boson to the charged leptons. In addition to the direct LHC searches for FV $Z$ decays to leptons, we investigate indirect bounds from flavor-conserving $Z$ decays to leptons at 1-loop, bounds from LEP searches, Electroweak Precision Observables (EWPO), $\ell_{i}\to\ell_{j}γ$ decays, $\ell_{i}\to3\ell_{j}$ decays, $\ell_{i}\to\ell_{j}+\text{inv.}$ decays, FV meson decays to leptons, FV $τ$ decays to $μ(e)$ + mesons, muon conversion in nuclei, and from muonium-antimuonium oscillations. For FV $Z$ couplings to $τμ$, we find that $τ\toμγ$ yields the strongest bounds, with a level reaching $\mathcal{O}(10^{-5})$, followed by bounds from $τ\to3μ(μee)$. For FV $Z$ couplings to $τe$, we find that the strongest bounds arise from the decay $τ\toμμe$, reaching $\mathcal{O}(10^{-7})$ as well, with bounds from $τ\to3e$ also yielding strong bounds. For FV $Z$ couplings to $μe$, we find that the strongest bounds are obtained from the decay $μ\to3e$, reaching $\mathcal{O}(10^{-11})$, with bounds from $μ\to eγ$, muon conversion, $K_{L}^{0}\rightarrowμe$ and $μ\to e+\text{inv.}$ also providing strong bounds. We also study projections from future experiments, such as the FCC-ee, Belle II and the Mu2e experiment. For the $Z$ couplings to $τμ$, we find that future experiments could improve the bound to $\mathcal{O}(10^{-6})$, whereas for the $Z$ couplings to $τe$, we find that future experiments could improve the bound to $\mathcal{O}(10^{-8})$, and for the $Z$ couplings to $μe$, they could improve the bound to $\mathcal{O}(10^{-13})$

hep-ph

Novel and Updated Bounds on Flavor-Violating Z Interactions in the Quark Sector

We derive bounds on the flavor-violating (FV) couplings of the $Z$ boson to quarks and present future sensitivity projections. Our analysis shows that the current bounds on the FV couplings are $\mathcal{O}(10^{-9})$ for the $Z$ couplings to $cu$ and $sd$, $\mathcal{O}(10^{-7})$ for $bd$, $\mathcal{O}(10^{-6})$ for $bs$, and $\mathcal{O}(10^{-3})$ for $tu$ and $tc$. Overall, low-energy flavor experiments provide significantly stronger constraints on these FV couplings than current collider searches.

hep-ph

Phenomenology of the Minimal Scale Invariant Two-Higgs-Doublet Model

We perform a comprehensive phenomenological analysis of the Scale Invariant Two Higgs Doublet Model (\textit{SI2HDM})~\cite{Lee:2012jn}. In this framework, the electroweak symmetry breaking is triggered radiatively, and the entire scalar mass spectrum, including that of the $125$ \textrm{GeV} Higgs boson, is generated at the one loop level. After imposing stringent theoretical and experimental constraints, a highly constrained viable parameter space is identified, where the SM-like Higgs mass is purely radiative. The model predicts substantial suppression in the triple Higgs couplings and the di-Higgs production cross section at the LHC13, which can be reduced by up to $45.5~\%$ compared to the Standard Model prediction.

hep-ph

Reinterpretation and preservation of data and analyses in HEP

Data from particle physics experiments are unique and are often the result of a very large investment of resources. Given the potential scientific impact of these data, which goes far beyond the immediate priorities of the experimental collaborations that obtain them, it is imperative that the collaborations and the wider particle physics community publish and preserve sufficient information to ensure that this impact can be realised, now and into the future. The information to be published and preserved includes the algorithms, statistical information, simulations and the recorded data. This publication and preservation requires significant resources, and should be a strategic priority with commensurate planning and resource allocation from the earliest stages of future facilities and experiments.

hep-ph

The 95 GeV Excess in the Georgi-Machacek Model: Single or Twin Peak Resonance

In this work, we investigate the possibility to address the excess observed around 95 GeV in the $γγ$, $ττ$, and $b\bar{b}$ channels as a scalar resonance(s) within the Georgi-Machacek (GM) model. In our analysis, we find that the excess can be easily accommodated in the channels ($γγ$ and $b\bar{b}$) simultaneously, where the 95 GeV candidate is a single peak resonance (SPR) due to a light CP-even scalar. We found that the excess in the $ττ$ channel can be addressed simultaneously with $γγ$ and $b\bar{b}$ only if the 95 GeV candidate is a twin peak resonance (TPR), i.e., another CP-odd scalar in addition to the CP-even scalar. We demonstrate that the nature of the 95 GeV scalar resonance candidate (SPR or TPR) can be probed via the properties of its di-$τ$ decay.

hep-ph

The scale invariant scotogenic model: CDF-II $W$-boson mass and the 95 GeV excesses

The anomalies observed in the $W$ mass measurements at the CDF-II experiments and the excesses seen around 95~GeV at the Large Hadron Collider (LHC) motivate this work, in which we investigate and constrain the parameter space of the Scale Invariant Scotogenic Model with a Majorana dark matter candidate. The scanned parameters are chosen to be consistent with the dark matter relic density and the observed excesses at $\sim95$~GeV signal strength rates in different channels. We found that significant part of the viable space addresses the excess in the channel $γγ$, while a tight part can address the excess in both $γγ$ and $b\bar{b}$ channels. Furthermore, the model's viable parameters can be probed in both the LHC and future $e^{+}e^{-}$ colliders for di-Higgs production.

hep-ph

Gravitational Waves from Phase Transitions in Scale Invariant Models

We investigate the properties of the gravitational waves (GWs) generated during a strongly first order electroweak phase transition (EWPT) in models with the classical scale invariance (CSI). Here, we distinguish two parameter space regions that correspond to the cases of (1) light dilaton and (2) purely radiative Higgs mass (PRHM). In the CSI models, the dilaton mass, or the Higgs mass in the PRHM case, in addition to some triple scalar couplings are fully triggered by the radiative corrections (RCs). In order to probe the RC effects on the EWPT strength and on the GW spectrum, we extend the standard model by a real singlet to assist the electroweak symmetry breaking and an additional scalar field $Q$ with multiplicity $N_Q$ and mass $m_Q$. After imposing all theoretical and experimental constraints, we show that a strongly first order EWPT with detectable GW spectra can be realized for the two cases of light dilaton and PRHM. We also show the corresponding values of the relative enhancement of the cross section for the di-Higgs production process, which is related to the triple Higgs boson coupling. We obtain the region in which the GW spectrum can be observed by different future experiments such as LISA and DECIGO. We also show that the scenarios (1) and (2) can be discriminated by future GW observations and measurements of the di-Higgs productions at future colliders.

hep-ph

More Constraints on the Georgi-Machacek Model

In this work, we investigate the parameter space of the Georgi-Machacek (GM) model, where we consider many theoretical and experimental constraints such as the perturbativity, vacuum stability, unitarity, electroweak precision tests, the Higgs di-photon decay, the Higgs total decay width and the LHC measurements of the signal strengths of the SM-like Higgs boson $h$ in addition to the constraints from doubly charged Higgs bosons and Drell-Yan di-photon production and the indirect constraint from the $b\to s$ transition processes. We investigate also the possibility that the electroweak vacuum could be destabilized by unwanted wrong minima that may violate the CP and/or the electric charge symmetries. We found that about 40 \% of the parameter space that fulfills the above mentioned constraints; are excluded by these unwanted minima. In addition, we found that the negative searches for a heavy resonance could exclude a significant part of the viable parameter space; and future searches could exclude more regions in the parameter space.

hep-ph

Constraining the Georgi-Machacek Model with a Light Higgs

In this work, we investigate the viability of a light Higgs ($η$) scenario in the Georgi-Machacek (GM) model, where we consider all theoretical and experimental constraints such as the perturbativity, vacuum stability, unitarity, electroweak precision tests, the Higgs di-photon and undetermined decays and the Higgs total decay width. In addition, we consider more recent experimental bounds from the searches for doubly-charged Higgs bosons in the VBF channel $H_{5}^{++}\rightarrow W^{+}W^{+}$, Drell-Yan production of a neutral Higgs boson $pp\rightarrow H_{5}^{0}(γγ)H_{5}^{+}$, and for the light scalars at LEP $e^{-}e^{+}\rightarrow Zη$, and at ATLAS and CMS in different final states such as $pp\rightarrowη\rightarrow2γ$ and $pp\rightarrow h\rightarrowηη\rightarrow4γ,2\mu2τ,2\mu2b,2\tau2b$. By combining these bounds together, we found a parameter space region that is significant as the case of the SM-like Higgs to be the light CP-even eigenstate, and this part of the parameter space would be tightened by the coming analyses.

hep-ph

A Scotogenic Model with Two Inert Doublets

In this work, we present a scotogenic model, where the neutrino mass is generated at one-loop diagrams. The standard model (SM) is extended by three singlet Majorana fermions and two inert scalar doublets instead of one doublet as in the minimal scotogenic model. The model scalar sector includes two CP-even, two CP-odd and two charged scalars in addition to the Higgs. The dark matter (DM) candidate could be either the light Majorana fermion (Majorana DM), or the lightest among the CP-even and the CP-odd scalars (scalar DM). We show that the model accommodates both Majorana and scalar DM within a significant viable parameter space, while considering all the relevant theoretical and experimental constraints such as perturbativity, vacuum stability, unitarity, the di-photon Higgs decay, electroweak precision tests and lepton flavor violating constraints. In addition to the collider signatures predicted by the minimal scotogenic model, our model predicts some novel signatures that can be probed through some final states such as $8~jets+\slashed{E}_T$, $1\ell+4~jets+\slashed{E}_T$ and $4b+\slashed{E}_T$.

hep-ph

Dark Matter in a Singlet Extended Inert Higgs Doublet Model

In this work, we consider an extension of the Standard Model (SM) with an inert Higgs doublet and a real scalar singlet, in order to address problems around the origin of dark matter (DM). In this model, the lightest among the CP-odd and CP-even neutral inert components plays the role of a DM candidate, where the model parameters are subject to many theoretical and experimental constraints. These constraints include vacuum stability, perturbativity, LEP negative searches, electroweak precision tests, Higgs di-photon, Higgs invisible and Higgs undetermined decays, DM relic density and DM direct detection bounds. Using these constraints, we find that the allowed parameter space for these models is quite sizeable and could be explored in upcoming collider and astrophysical searches.

hep-ph

Purely Radiative Higgs Mass in Scale invariant models

In this work, we investigate the possibility of having scale invariant (SI) standard model (SM) extensions, where the light CP-even scalar matches the SM-like Higgs instead of being a light dilaton. After deriving the required conditions for this scenario, we show that the radiative corrections that give rise to the Higgs mass can trigger the scalar mixing to the experimentally allowed values. In addition, we discuss the constraints on the parameters space that makes the CP-even scalars properties in a good agreement with all the recent ATLAS and CMS measurements. We illustrate this scenario by considering the SI-scotogenic model as an example, while imposing all the theoretical and experimental constraints. We show that the model is viable and leads to possible modifications of the di-Higgs signatures at current/future with respect to the SM.

hep-ph

The Scale Invariant Scotogenic Model: Dark Matter and the Scalar Sector

In this paper, we investigate the mutual impact between the dark matter (DM) requirements and the scalar sector in the scale invariant (SI) scotogenic model. The model is motivated by the neutrino mass and DM within a classically SI framework. It is a SI generalization of the scotogenic model, where the standard model (SM) is extended by a real singlet, an inert scalar doublet and three Majorana singlet fermions, where the lightest one ($N_{1}$) could play the DM candidate role. In addition to the annihilation channels $N_{1}N_{1}\rightarrow\ell_α\ell_β,ν_α\barν_β$, the DM can be annihilated via few s-channel processes into SM particles, that are mediated by the Higgs/dilaton. This allows the new Yukawa interactions, that are responsible for neutrino mass generation, to take small values and therefore avoid the mass degeneracy between the CP-even and CP-odd inert scalars unlike the case of the minimal scotogenic model. In contrast to many Majorana DM models, the DM in the SI-scotogenic model couples to the quarks at tree-level, and hence the constraint from the direct detection experiments is very important on the space parameter. The aim of this work is to investigate the correlation between the DM requirements and the scalar sector in this model.

hep-ph

Phenomenology of the Hidden SU(2) Vector Dark Matter Model

We investigate the phenomenology of an extension of the Standard Model (SM) by a non-abelian gauge group $SU(2)_{HS}$ where all SM particles are singlets under this gauge group, and a new scalar representation $ϕ$ that is singlet under SM gauge group and doublet under $SU(2)_{HS}$. In this model, the dark matter (DM) candidates are the three mass degenerate dark photons $A_{i}$ $(i=1,2,3)$ of $SU(2)_{HS}$; and the hidden sector interacts with the (SM) particles through the Higgs portal interactions. Consequently, there will be a new CP-even scalar $η$ that could be either heavier or lighter than the SM-like Higgs. By taking into account all theoretical and experimental constraints such as perturbativity, unitarity, vacuum stability, non-SM Higgs decays, DM direct detection, DM relic density, we found viable DM is possible in the range from GeV to TeV. Within the viable parameters space, the both of the triple Higgs coupling and the di-Higgs production at LHC14 could be enhanced or reduced depending on the scalar mixing and the mass of the scalar particle $η$.

hep-ph

A Natural Scotogenic Model for Neutrino Mass \& Dark Matter

In this letter, we propose an extension of the scotogenic model where singlet Majorana particle can be dark matter (DM) without the need of a highly suppressed scalar coupling of the order $O(10^{-10})$. For that, the SM is extended with three singlet Majorana fermions, an inert scalar doublet, and two (a complex and a real) singlet scalars, with a global $Z_{4}$ symmetry that is spontaneously broken into $Z_{2}$ at a scale higher than the electroweak one by the vev of the complex singlet scalar. In this setup, the smallness of neutrino mass is achieved via the cancellation between three diagrams a la scotogenic, a DM candidate that is viable for a large mass range; and the phenomenology is richer than the minimal scotogenic model.

hep-ph

Reinterpretation of LHC Results for New Physics: Status and Recommendations after Run 2

We report on the status of efforts to improve the reinterpretation of searches and measurements at the LHC in terms of models for new physics, in the context of the LHC Reinterpretation Forum. We detail current experimental offerings in direct searches for new particles, measurements, technical implementations and Open Data, and provide a set of recommendations for further improving the presentation of LHC results in order to better enable reinterpretation in the future. We also provide a brief description of existing software reinterpretation frameworks and recent global analyses of new physics that make use of the current data.

hep-ph

Mono-Higgs Signature in the Scotogenic Model with Majorana Dark Matter

We study the phenomenology of scotogenic model in the case of Majorana Dark Matter (DM) candidate. This scenario gives important consequences since the parameter space of the model is almost unconstrained compared to the Inert Higgs Doublet Model (or the scotogenic model with scalar DM), and hence, offers new opportunities for discovery at future high energy collider, e.g. the HL-LHC. As an example, we focus on the production of the Standard Model (SM) Higgs boson in association with a pair of dark scalars. Owing to its clean signature, the $γγ$ decay channel of the SM Higgs boson is investigated in great detail at both the HL-LHC (at $\sqrt{s}=14$ TeV) and the future FCC-hh (at $\sqrt{s}=100$ TeV). After revisiting the LHC constraints from run-II on the parameter space of the model, and selecting benchmark points satisfying all the theoretical and experimental constraints, we found that scalars with mass up to $140$ GeV ($160$ GeV) can be probed at the LHC (FCC-hh) with a $3$ ab$^{-1}$ of integrated luminosity assuming $5\%$ of uncertainty.

hep-ph