arXiv subjects

E. Cruz-Albaro

Publications and source records attributed to E. Cruz-Albaro.

12 recordsLinked to original sources

arXiv2026

Production of the top partner $T$ of the Bestest Little Higgs Model at the future muon collider

In this work, we evaluate the decay widths and branching ratios of the heavy top partner $T$, and perform a comprehensive phenomenological study of its pair and associated production at a muon collider within the framework of the Bestest Little Higgs Model (BLHM). The BLHM provides an attractive and natural mechanism for addressing the fine-tuning problem in the Standard Model (SM) of particle physics. In our study of the top partner $T$, we consider the production processes $μ^{+} μ^{-} \to (γ, Z, Z', h, H) \to T \bar{T}$ and $μ^{+} μ^{-} \to (γ, Z, Z', h, H)\to \bar{t}T+ t \bar{T}$, and we explore different center-of-mass energies of the muon collider to perform our numerical analysis of the production cross sections for the processes of interest. Our results show that pair production is the most promising channel for probing the top partner of the BLHM at a future muon collider.

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arXiv2025

Search for pseudoscalar Higgs boson $A_0$ of the Bestest Little Higgs model at the LHC and FCC-hh

We analyse the sensitivity of the Large Hadron Collider (LHC) and the Future Circular Collider-hadron-hadron (FCC-hh) to the existence of pseudoscalar Higgs boson $A_0$ predicted by the Bestest Little Higgs model. We study the tree-level (two and three body) and one-loop decays of the pseudoscalar, $A_0 \to b\bar b, t \bar t, γt\bar t, γb \bar b, Zt\bar t, Zb \bar b, Wt\bar b, h_0 t \bar t, h_0 b \bar b$, and $A_0 \to γγ, γZ, ZZ, gg, WW$, respectively. In addition, we perform a phenomenological study of the production of the pseudoscalar $A_0$ via gluon fusion $gg \to A_0 \to Y$ processes, where $Y \equiv γγ, γZ, ZZ, gg, WW$. From the cross section of the processes of interest and the expected integrated luminosity of the LHC and FCC-hh, we determined the number of events that could be produced in both colliders.

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arXiv2025

The new $Z'$ boson of the Bestest Little Higgs Model as a portal to signatures of Higgs bosons $h_0$ and $H_0$ at the future muon collider

We study the new $Z'$ boson as a portal for the production of Higgs bosons $h_0$ and $H_0$ predicted by the Bestest Little Higgs Model through the Higgs-strahlung processes $μ^+μ^- \to (Z, Z') \to Zh_0, ZH_0$. We focus on the resonance and non-resonance effects of the $Zh_0, ZH_0$ signals. In our analysis, we consider the center-of-mass energies of $\sqrt{s}=3, 4, 6, 10, 30$ TeV and integrated luminosities of ${\cal L}=2, 4, 6, 10, 30$ ${\rm ab^{-1}}$ projected for a future muon collider. The possibility of performing precision measurements for the Higgs bosons $h_0$ and $H_0$ is very promising at the future muon collider. Furthermore, our results may be helpful to the High Energy Physics community. Complementarily, we generate and provide the Feynman rules necessary for studying the processes $μ^+μ^- \to (Z, Z') \to Zh_0, ZH_0$.

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arXiv2024

New physics search with the new gauge boson $Z'$ of the bestest little Higgs model at the muon collider

The Bestest Little Higgs Model (BLHM) has attracted increasing attention in recent years, mainly because it can explain the hierarchy problem without fine-tuning by introducing one-loop corrections to the Higgs boson mass through heavy top quark partners and heavy gauge bosons. In the context of this new model, we exhaustively investigated the impact of the BLHM parameters on the Higgs-strahlung production processes $μ^{-} μ^{+} \to Z'h_0$ and $μ^{-} μ^{+} \to Z'H_0$, where $Z'$ and $H_0$ represent a new heavy gauge boson and a new heavy Higgs boson, respectively. We consider the integrated luminosities of ${\cal L}=2000, 20 000$ ${\rm fb^{-1}}$ and the respective center-of-mass energies of $\sqrt{s}=3000, 10 000$ GeV projected for a future muon collider to estimate the number of expected Higgs boson production events $h_0$ or $H_0$ in association with a new gauge boson $Z'$ at the muon collider. In addition, we derive and present the Feynman rules for scalars ($h_0, H_0, ϕ^{0}, η^{0}, σ, H^{\pm}, ϕ^{\pm}, η^{\pm}, A_0$) and include the self-interactions of Higgs bosons.

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arXiv2024

Chromomagnetic dipole moments of light quarks in the Bestest Little Higgs Model

In this paper, we research into the anomalous Chromomagnetic Dipole Moment (CMDM), denoted as $\hatμ_{q}^{BLHM}$, of the light quarks $q=(u, c, d, s, b)$ within the framework of the Bestest Little Higgs Model (BLHM) as an extension of the Standard Model (SM). Our investigation encompasses novel interactions among the light quarks, the heavy quark $B$, and the heavy bosons $(W^{\prime\pm}, H^{\pm}, ϕ^{\pm}, η^{\pm})$, incorporating the extended Cabibbo-Kobayashi-Maskawa (CKM) matrix characteristic of the BLHM. We thoroughly explore the permissible parameter space, yielding a spectrum of CMDM values ranging from $10^{-10}$ to $10^{-3}$.

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arXiv2024

Probing the heavy Higgs boson production and decay $H_0$ of the Bestest Little Higgs Model at the LHC and the FCC-hh

In the Bestest Little Higgs Model (BLHM) scenario, we analyze the branching ratios and production cross-section of the heavy Higgs boson $H_0$. The analysis is performed at the tree level and the one-loop level. In addition, we present results of the possible production of the heavy Higgs boson $H_0$ via gluon fusion for the center-of-mass energies and the integrated luminosities of the LHC, HE-LHC, HL-LHC, and FCC-hh. Our results show a very optimistic scenario for studying the $H_0$ scalar predicted by the BLHM and for the energies and luminosities of current and future hadron colliders.

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arXiv2023

Flavor-changing top quark rare decays in the Bestest Little Higgs Model

This paper investigates the effects of parameters in the Bestest Little Higgs Model (BLHM) on rare flavor-changing decays of the top quark. As a result, flavor-changing phenomena are introduced in the BLHM for the first time. In this study, we incorporate new flavor mixing terms between the light quarks of the Standard Model (SM) and the fermions and bosons of the BLHM. We compute the one-loop contributions from the heavy quark $(B)$ and the heavy bosons $(W^{\prime\pm}, ϕ^{\pm}, η^{\pm},H^{\pm})$. Our findings demonstrate that the branching ratios of decays $t\to qV$ and $t\to qh^0$, where $q=u,c$ and $V=Z, γ, g $, exhibit improvements compared to their counterparts in the SM, except for the gluon case. Moreover, we observe that the processes with higher sensitivity are $Br(t\to cZ)\sim 10^{-5}$, $Br(t\to cγ)\sim 10^{-6}$ and $Br(t \to ch^0) \sim 10^{-8}$ within the appropriate parameter space.

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arXiv2023

Searching the anomalous electromagnetic and weak dipole moments of the top-quark at the Bestest Little Higgs Model

In this paper, using a Bestest Little Higgs Model (BLHM) approach, we obtain bounds on the top-quark electromagnetic and weak dipole moments. These physical observables are sensitive to quantum corrections induced by virtual particles at the one-loop level. The contributions of the virtual particles are obtained from the vertices of scalar bosons, vector bosons, and heavy quarks: $tq_iS_i$, $S_i=h_0, H_0, A_0, ϕ^{0}, η^{0}, σ, H^{\pm}, ϕ^{\pm}, η^{\pm}$; $tq_iV_i$, $V_i= γ, Z, W, Z', W'$; $V q_i\bar q_i$, $V=γ,Z$, $q_i=b, t, B, T, T_5, T_6, T^{2/3}, T^{5/3}$; $ V W^{-}_{i}Φ^{+}_i $, $W_{i} \equiv W, W'$, $Φ^{\pm}_{i}= ϕ^{\pm}, η^{\pm}$; $ZZH_i$, $H_i=h_0, H_0$; $ZZ' H_i$; and $VW'W'$. With these new contributions, we evaluated the electroweak dipole moments $ a_t$, $ a^{W}_t $, $ d_t $ and $ d^{W}_{t} $ of the top-quark in the diagonalization schemes $y_2 > y_3$ and $y_2 < y_3$ to the Yukawa couplings. For the BLHM parameters, we choose the following values of $m_{A_0}= 1000$ GeV, $m_{η^0}= 100$ GeV, $f=[1000, 3000]$ GeV, $F=[3000, 6000]$ GeV and $\tanβ=3$, which give the best sensitivity on the electroweak dipole moments of the top-quark in this context: $a_t=1.39 \times 10^{-4} + i\, 6.55 \times 10^{-5}$; $a^{W}_t=6.31 \times 10^{-5} - i\, 1.39 \times 10^{-5}$ for the $y_2 > y_3 $ scenario, while $a_t= 2.12 \times 10^{-4} + i\, 4.49 \times 10^{-5}$; $a^{W}_t= 2.13 \times 10^{-4} - i\, 1.34 \times 10^{-5}$ for the $y_2 < y_3 $ scenario.

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arXiv2022

Research on the electromagnetic and weak dipole moments of the tau-lepton at the Bestest Little Higgs Model

In this paper, using the Bestest Little Higgs Model (BLHM) we calculate at the one-loop level the contributions to the Anomalous Magnetic Dipole Moment (AMDM) and Anomalous Weak Magnetic Dipole Moment (AWMDM) of the tau-lepton. The implications from this model are study, emphasizing the contributions of the new physics induced by the new scalar and vector bosons of the BLHM: $S_i=H_0, A_0, ϕ^{0}, η^{0}, σ, H^{\pm}, ϕ^{\pm}, η^{\pm}$, and $V_i=Z', W'$, because these quantify the new physics. With these new contributions we estimated bounds on both the real and imaginary parts of the AMDM and AWMDM of the tau-lepton. Our study complements other one-loop level research performed on models beyond the Standard Model.

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arXiv2022

Sensitivity limits on the weak dipole moments of the top-quark at the Bestest Little Higgs Model

We presented new researches for the sensitivity limits on the weak dipole moments of the top quark-$Z$ boson interactions in the context of the Bestest Little Higgs Model (BLHM). For this purpose, we derive the corresponding Feynman rules. Among the new contributions, there are those arising from the vertices of scalar bosons, vector bosons and heavy quarks contribution: $tq_iS_i$, ($S_i=h_0, H_0, A_0, ϕ^{0}, η^{0}, σ, H^{\pm}, ϕ^{\pm}, η^{\pm}$); $tq_iV_i$, ($V_i= γ, Z, W, Z', W'$); and $Zq_i\bar q_i$ ($q_i=b, t, B, T, T_5, T_6, T^{2/3}, T^{5/3}$). With these new vertices, we calculate the one-loop contributions to the weak dipole moments $a^W_t$ and $d^W_t$ of the top-quark in several scenarios. We found that with the parameters of the BLHM of $m_{A_0}= 1000$ GeV, $m_{η^0}= 100$ GeV, $F=4000$ GeV, $f=[1000, 3000]$ GeV and $\tanβ=3$, the $a^W_t$ reaches values with a sensitivity of $a^{W}_{t}= 2.49 \times 10^{-4}-1.26 \times 10^{-5}i$, $1.26 \times 10^{-4}-5.41\times 10^{-6}i$, where the main contribution comes from the scalars $h_0$ and $H_0$, which couples to the top-quark of the Standard Model and the top-quarks of the BLHM. These values seem to be out of the reach of the expected experimental sensitivity of present experiments. However, experiments on future colliders are expected to be sensitive enough to measure the AWMDM of the top-quark. Our study complements other studies at the level of one-loop with an extended scalar sector.

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arXiv2021

Chromomagnetic dipole moment of the top quark in the Bestest Little Higgs model

We calculate the chromomagnetic dipole moment of the top quark, $\hatμ_t$, in the context of the Bestest Little Higgs model. This extension of the Standard Model aims to solve the hierarchy problem without fine tuning, by introducing one-loop corrections to the Higgs boson mass through heavy top quark partners and heavy gauge bosons. We found that the largest resulting value for the chromomagnetic is $\hatμ_t\sim 10^{-5}$ and the lowest is around $10^{-6}$, mainly due to the Higgs boson of the Standard Model, which couples to both the top quark of the Standard Model and its heavy partners. Also, we present a wide variety of new Feynman rules involved in our calculation.

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arXiv2017

Heavy neutral pseudoscalar decays into gauge bosons in the Littlest Higgs Model

We study two-body decays of a new neutral pseudoscalar into gauge bosons within the context of the Littlest Higgs model. Concretely, the $Φ^P \to WW, VV, gg$ processes induced at the one-loop level, with $V=γ, Z$, are considered. Since the branching ratios of the $Φ^P \to VV$ decays result very suppressed, only the $Φ^P \to WW, gg$ processes are thoroughly studied. The branching ratios for the $Φ^P \to gg$ and $Φ^P \to WW$ decays are of the order of $10^{-4}$ and $10^{-6}$, respectively, for $f$ around 2 TeV, which represents the global symmetry breaking scale of the theory. The production cross section of the $Φ^P$ boson via gluon fusion at LHC is estimated.

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