arXiv subjects

S. Rosado-Navarro

Publications and source records attributed to S. Rosado-Navarro.

11 recordsLinked to original sources

arXiv2026

Probing Flavor-Violating Higgs Decays in the Type-III Two-Higgs-Doublet Model at the LHC and HL-LHC

We present a comparative collider study of three flavor-violating Higgs signatures in the Type-III Two-Higgs-Doublet Model (\ddHmIII) at $\sqrt{s}=14$~TeV: $pp \to H \to t\bar{c} \ (\bar{t}c)$, $pp \to H^\pm \to c\bar{b} \ (\bar{c}b)$, and $pp \to H^\pm \to t\bar{b} \ (\bar{t}b)$. Using a common cut-based analysis and realistic detector simulation, we identify a clear phenomenological hierarchy. The neutral mode and the heavy charged mode emerge as the most robust signatures, containing parameter regions that already exceed the $5σ$ benchmark at an integrated luminosity of $300~\text{fb}^{-1}$. In contrast, the light charged channel $H^{\pm}\to c\bar{b}$ is considerably more sensitive to the event-selection strategy because of large QCD backgrounds, although one competitive benchmark survives. Our results single out the neutral and heavy charged flavor-violating channels as the most promising targets for discovery-oriented searches and for constraining the \ddHmIII\ parameter space at the LHC and HL-LHC. All quoted significances are purely statistical and do not include systematic uncertainties.

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arXiv2026

Lepton flavor violation in Higgs boson decays at the HL-LHC

We explore the discovery potential for lepton flavor-violating Higgs boson decays, $h \to \ell_i \ell_j$ ($\ell_i \neq \ell_j$; $\ell = e, μ, τ$), in proton-proton collisions. The analysis is performed within a Froggatt-Nielsen framework, which offers a well-motivated theoretical mechanism for such processes. By performing a systematic scan over the phenomenologically viable parameter space, we identify regions that can yield observable signatures at the High-Luminosity LHC (HL-LHC). For an integrated luminosity of $\mathcal{L}_{\rm int} \gtrsim 1000~\text{fb}^{-1}$, we project that the channels $h \to eμ$ and $h \to τμ$ (with $τ^{\pm} \to π^{\pm} ν_τ$) could reach the $5σ$ discovery threshold, while $h \to τe$ remains inaccessible even at $3000~\text{fb}^{-1}$. Our results highlight the unique capability of the HL-LHC to probe new physics through searches for rare Higgs decays.

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arXiv2026

Production of dark matter in association with a Higgs boson via exclusive photon fusion in $pp$ collisions at $\sqrt{s}=13$ TeV

In this work we study the production of a dark matter (DM) particle in association with a Higgs boson via a central exclusive photon-fusion initiated process. We explore this type of production through the Inert Doublet Model plus a complex Singlet (IDMS), where an extension of the Standard Model by an additional $U(1)_X$ gauge symmetry and a $SU(2)$ inert scalar doublet gives rise to a DM candidate $χ$. This particular process involves the collision of two protons exchanging two colorless particles (in our case, photons), from which a central process occurs. Such interaction can be detected in the LHC using forward proton detectors, where the resulting missing mass spectrum can be observed after proton reconstruction, thus allowing a search for physics Beyond the Standard Model (BSM). We present results for different values of the difference of masses of a heavy scalar coming from the complex singlet, the DM candidate and the Higgs boson, $Δ= M_S - M_χ- M_h$, which is the phase space available for the final state in the central exclusive process.

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arXiv2025

Lepton flavor violation in photon-induced electron-muon pairs at the HL-LHC

We show the outstanding potential of the High-Luminosity LHC (HL-LHC) to discover charged lepton flavor violation (cLFV) via the ultra-peripheral process $γγ\to e^\pmμ^\mp$. Using a gauge-invariant Effective Field Theory (EFT) framework -consistent with the most stringent bounds from radiative decays- we perform a full Monte Carlo analysis with multivariate techniques. Our results show that a $5σ$ discovery is achievable with an integrated luminosity of $\mathcal{L}_{\rm int} \gtrsim 2700$ fb$^{-1}$ for favorable benchmark scenarios. This study establishes photon-fusion at the HL-LHC as a powerful probe of cLFV, strongly motivating dedicated searches by the experimental collaborations.

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arXiv2024

Hunting a charged Higgs boson pair in proton-proton collisions

We explore the production and possible detection of a charged scalar Higgs pair $H^-H^+$ decaying into the final state $μν_μcb$ in proton-proton collisions at the LHC and its next step, the High Luminosity LHC (HL-LHC). The charged scalars are predicted within the theoretical framework of the Two-Higgs Doublet Model of type III (2HDM-III). As a test and validation of the model, we identify regions of the 2HDM-III parameter space that accommodate the current excess of events at $3σ$ in the process $\mathcal{BR}(t\to H^{\pm}b)\times \mathcal{BR}(H^{\pm}\to cb)$ for $M_{H^{\pm}}=130$ GeV, as reported by the ATLAS collaboration. Theoretical and additional experimental constraints are also included. Based on this, we propose realistic scenarios that could be brought under experimental scrutiny at the HL-LHC. Assuming the most favorable scenario, we predict a signal significance at the level of $5σ$ for a charged scalar boson mass $M_{H^{\pm}}$ in the $100-350$ GeV range.

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arXiv2022

Production of charged Higgs $H^\pm$ through $cb$-fusion at LHC

Considering the framework of the 2-Higgs Doublet Model Type III (2HDM-III), wherein two doublets are coupled both to up as down fermions, and the Flavour Changin Currents (FCNCs) is controlled by a four-zero Texture approach in the Yukawa matrices. We study the production of charged Higgs ($H^\pm$) by means of $cb$ quark fusion followed by channel decay $H^\pm \to τ^\pm ν$ : $ c b \to H^\pm \to τ^\pm \bar ν$. Taking in account the experimental bounds, as well as the theoretical constraints analysed in previous work arXiv:2003.06263[hep-ph]. One can show that in a lepton-specific-like incarnation of the model, we obtain a significant sensitivity for the LHC machine. We consider in the aforementioned study to both irreducible and reducible backgrounds of the SM.

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arXiv2020

Charged Higgs boson production via $cb-$fusion at the Large Hadron Collider

We analyse the production of a light charged Higgs boson at the Large Hadron Collider (LHC) via the quark-fusion mechanism $c \bar{b} \to H^- $ considering the decay channel $H^- \to τ\bar ν_τ$ in the final state. We study this process in the framework of the 2-Higgs Doublet Model Type III (2HDM-III) which assumes a four-zero texture in the Yukawa matrices and a general Higgs potential, wherein the two Higgs doublets coupling to both up and down fermions do generate Flavour Changing Neutral Currents (FCNCs) yet the latter can be controlled by the texture when flavour physics constraints are considered. We consider the parameter space of the model where this signal is enhanced and in agreement with both theoretical constraints and experimental data. In particular, we exploit the setup with lepton-specific-like Yukawa couplings and assess the LHC sensitivity to such $H^\pm$ signals against the dominant {irreducible and} reducible backgrounds. We show that in our model BR$(H^\pm \to cb) \sim 0.1- 0.2$ and BR$(H^\pm \to τν) \sim 0.7-0.9$ so that, under these conditions, the prospects for $H^\pm$ detection in the 2HDM-III in the aforementioned production and decay channels are excellent assuming standard collider energy and luminosity conditions.

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arXiv2019

A classical lower bound on the size of a massive neutrino

In this paper, we calculate the size of a massive neutrino in the following approach. We perform our calculation using its mass, spin, and magnetic moment through the neutrino-electron interaction, $via$ the classical magnetic dipole-dipole interaction. Thus, our estimate is obtained by mimicking the low-energy electroweak scattering process $ν_l$-$l^{\prime}$. This leads to surprisingly accurate result which differs in less than one order of magnitude of more detailed calculations with one-loop corrections based on the neutrino charge radius and the $ν_l$-$l^{\prime}$ scattering process. The resulting estimates are flavour-blind and gauge independent by construction. We also find that our lower bound is below the reported experimental upper bound on the electron neutrino charged radius. So we obtained a constraining range for the neutrino size.

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arXiv2019

Light charged Higgs boson production at future $ep$ colliders

We present a recent study of light charged Higgs boson ($H^-$) production at the Large Hadron electron Collider (LHeC). We study the charged current production process $e^- p \to ν_e q H^-$, taking in account the decay channels $H^- \to b\bar{c}$ and $H^-\to τ\barν_τ$. We analyse the process in the framework of the 2-Higgs Doublet Model Type-III (2HDM-III), assuming a four-zero texture in the Yukawa matrices and a general Higgs potential. We consider a variety of both reducible and irreducible backgrounds for the signals of the $H^-$ state. We show that the detection of a light charged Higgs boson is feasible, assuming for the LHeC standard energy and luminosity conditions.

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arXiv2019

Light charged Higgs boson production at the Large Hadron electron Collider

We study the production of a light charged Higgs boson at the future Large Hadron electron Collider (LHeC), through the process $e^- p \to ν_e H^- q$ considering both decay channels $H^- \to b \bar c$ and $H^- \to τ\bar ν_τ$ in the final state. We analyse these processes in the context of the 2-Higgs Doublet Model Type III (2HDM-III) and assess the LHeC sensitivity to such $H^-$ signals against a variety of both reducible and irreducible backgrounds. We confirm that prospects for $H^-$ detection in the 2HDM-III are excellent assuming standard collider energy and luminosity conditions.

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arXiv2010

Electroweak right-handed neutrinos and new signals at the LHC

We explore in detail the Higgs phenomenology that results in a model where right-handed neutrinos have a mass scale of the order of the electroweak scale. In this model all scales arise from spontaneous symmetry breaking, and this is achieved with a Higgs sector that includes an extra Higgs singlet in addition to the standard model Higgs doublet. The scalar spectrum includes two neutral CP-even states ($h$ and $H$ with $m_{h} < m_{H}$)and a neutral CP-odd state ($σ$) that can be identified as a pseudo-Majoron. The parameter of the Higgs potential are constrained using a perturbativity criteria. Higgs BR and cross-sections are discussed, with special emphasis on the detection at the LHC.

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