arXiv subjects

A. Gutiérrez-Rodríguez

Publications and source records attributed to A. Gutiérrez-Rodríguez.

At least 37 records · Page 2Linked to original sources

arXiv2019

Anomalous quartic $WWγγ$ couplings in $ep$ collisions at the LHeC and the FCC-he

We conducted a study on measuring $W^+W^-$ production and on the sensitivity limits at $95\%$ Confidence Level on thirteen anomalous couplings obtained by dimension-8 operators which are related to the anomalous quartic $WWγγ$ couplings. We consider the main $e^-p \to e^-γ^*γ^*p \to e^-W^+W^-p$ reaction with the sub-process $γ^*γ^* \to W^+W^-$ at the Large Hadron electron Collider (LHeC) and the Future Circular Collider-hadron electron (FCC-he). For the LHeC, energies of the $e^-$ beams are taken to be $E_e =60$ and 140 GeV and the energy of the $p$ beams is taken to be $E_p = 7$ TeV. For the FCC-he, energies of the $e^-$ beams are taken to be $E_e =60$ and 140 GeV and the energy of the $p$ beams is taken to be $E_p = 50$ TeV, respectively. It is interesting to notice that the LHeC and the FCC-he will lead to model-independent limits on the anomalous quartic $WWγγ$ couplings which are one order of magnitude stringent than the CMS Collaboration limits, in addition to being competitive with other limits reported in the literature.

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arXiv2019

Projections for model-independent sensitivity estimates on top-quark anomalous electromagnetic couplings at the FCC-he

The measurement of the top-quark anomalous electromagnetic couplings is one of the most important goals of the top-quark physics program in the present and future collider experiments. This would provide direct information on the non-standard interactions of the top-quark. We study a top-quark pair production scenario at the Future Circular Collider Hadron-Electron (FCC-he) through $e^-p \to e^-γ^*γ^*p \to e^-t\bar t p$ collisions, which will provide information about sensitivities on anomalous $\hat a_V$ and $\hat a_A$ couplings at $95\%\hspace{0.8mm}C.L.$, and the possibility of probing new physics. Energy of the $e^-$ beams is taken to be $E_e=250\hspace{0.8mm}GeV$ and $500\hspace{0.8mm}GeV$ and the energy of the $p$ beams is taken to be $E_p=50\hspace{0.8mm}TeV$, with these energies the FCC-he may sensitivity estimates on top-quark electromagnetic dipole moments $\hat a_V$ and $\hat a_A$ of the order ${\cal O}(10^{-2}-10^{-1})$.

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arXiv2019

Probing model-independent limits on $W^+W^-γ$ triple gauge boson vertex at the LHeC and the FCC-he

We study the cross-section of production of a single $W^-$ boson in association with a neutrino through the process $e^-p \to e^-γ^*p \to ν_eW^- p$. Additionally, we obtain the anomalous couplings $Δκ_γ$ and $λ_γ$ of the $W^+W^-γ$ vertex at the Large Hadron Electron Collider (LHeC) and the Future Circular Collider Hadron-Electron (FCC-he). The impact of the polarized beam due to the electron is also analyzed. Our best limits for $Δκ_γ$ and $λ_γ$ at the $95\%$ C.L. are: $Δκ_γ= \pm 0.0017$, $λ_γ= \pm 0.0053$ (unpolarized electron beam) and $Δκ_γ= \pm 0.0013$, $λ_γ= \pm 0.0046$ (polarized electron beam) identifying the $W^-$ boson through the hadronic decay channel. In addition, the $e^-γ^* \to ν_eW^-$ collision is one of the clean, pure and simple process to investigate the $W^+W^-γ$ coupling without the complications of QCD backgrounds.

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arXiv2019

Model-independent limits for anomalous triple gauge bosons $W^+W^-γ$ coupling at the CLIC

We investigate the potential of the Compact Linear Collider (CLIC) to probe the anomalous $W^+W^-γ$ coupling in $γγ$, $γγ^*$ and $γ^*γ^*$ collisions through the processes $γγ\rightarrow W^+ W^-$, $e^+ γ\rightarrow e^+ γ^{*} γ\rightarrow e^+ W^- W^+$ and $e^+ e^-\rightarrow e^+ γ^{*} γ^{*} e^- \rightarrow e^+ W^- W^+ e^-$. We perform leptonic, semi-leptonic and hadronic decays channels for $W^+W^-$ production in the final state. Taking ${\cal L}=1\hspace{0.8mm}{\rm ab^{-1}}@ \sqrt{s}=0.380\hspace{0.8mm}{\rm TeV}$, ${\cal L}=2.5\hspace{0.8mm}{\rm ab^{-1}}@ \sqrt{s}=1.5\hspace{0.8mm}{\rm TeV}$ and ${\cal L}=5\hspace{0.8mm}{\rm ab^{-1}}@ \sqrt{s}=3\hspace{0.8mm}{\rm TeV}$, based on future CLIC data, the limits for $Δκ_γ$ and $λ_γ$ might reach up to ${\cal O}(10^{-5}-10^{-4})$ level in the most ideal with 5\hspace{0.8mm}${\rm ab^{-1}}$ set data, which shows a potential advantage compared to those from LHC, Tevatron and LEP data. Thus, our results represent that the processes $γγ\rightarrow W^+ W^-$, $e^+ γ\rightarrow e^+ γ^{*} γ\rightarrow e^+ W^- W^+$ and $e^+ e^-\rightarrow e^+ γ^{*} γ^{*} e^- \rightarrow e^+ W^- W^+ e^-$ at the CLIC are a very good prospect for probing the anomalous $W^+W^-γ$ couplings.

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arXiv2019

Sensitivity measuring expected on the electromagnetic anomalous couplings in the $t\bar tγ$ vertex at the FCC-he

In this paper, we consider the electroweak production cross-section of a single anti-top-quark, a neutrino and a photon via charged current through the $e^-p \to e^-\bar b \to \bar t ν_e γ\to \bar t(\to W^- \to (qq', l^- \barν_l)+b) ν_eγ$ signal. Further, we derived the sensitivity expected to the magnetic dipole moment $(\hat a_V)$ and the electric dipole moment $(\hat a_A)$ of the top-quark at the Future Circular Collider Hadron Electron (FCC-he). We present our study for $\sqrt{s}=7.07, 10\hspace{0.8mm}TeV$, ${\cal L}=50, 100, 300, 500, 1000\hspace{0.8mm}fb^{-1}$, $δ_{sys}=0, 3, 5\hspace{0.8mm}\%$ and $P_{e^-}=0\%, 80\%, -80\%$, respectively. We find that the sensitivity estimated on dipole moments of the top-quark is of the order of magnitude ${\cal O}(10^{-1})$ for both hadronic and leptonic decay modes of $W^-$: $\hat a_V=[-0.2308, 0.2204]$, $|\hat a_A|=0.2259$ at $95\%$ C.L. in the hadronic channel with unpolarized electron beam $P_{e^-}=0\%$. Our results with polarized electron beam for $P_{e^-}=80\%$ and $P_{e^-}=-80\%$ are $\hat a_V=[-0.3428, 0.3321]$, $|\hat a_A|=0.3371$ and $\hat a_V=[-0.2041, 0.1858]$, $|\hat a_A|=0.1939$ at $95\%$ C.L. in the hadronic channel. The corresponding results for the leptonic channel with $P_{e^-}=0\%, 80\% -80\%$ are $\hat a_V=[-0.3067, 0.2963]$, $|\hat a_A|=0.3019$, $\hat a_V=[-0.4563, 0.4456]$, $|\hat a_A|=0.4505$ and $\hat a_V=[-0.2695, 0.2512]$, $|\hat a_A|=0.2592$, respectively. The results for $\hat a_V$ and $\hat a_A$ in the leptonic channel are weaker by a factor of 0.75 than those corresponding to the hadronic channel. Given these prospective sensitivities we highlight that the FCC-he is potential top-quark factory that is particularly well suited to sensitivity study on its dipole moments and with cleaner environments.

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arXiv2019

FCC-he sensitivity estimates on the anomalous electromagnetic dipole moments of the top-quark

In this paper, we study the production of a top-quark in association with a bottom-quark and a electron-neutrino at the Future Circular Collider Hadron Electron (FCC-he) to probe the sensitivity on its magnetic moment $(\hat a_V)$ and its electromagnetic dipole moment $(\hat a_A)$ through the process $e^-p \to e^-γp \to \bar t ν_e b p$. Assuming a large amount of collisions, as well as of data with cleaner environments, the FCC-he is an excellent option to study new physics, such as the $\hat a_V$ and $\hat a_A$. For our sensitivity study on $\hat a_V$ and $\hat a_A$, we consider center-of-mass energies $\sqrt{s}= 7.07, 10\hspace{0.8mm}TeV$ and luminosities ${\cal L}=50, 100, 300, 500, 1000\hspace{0.8mm}fb^{-1}$. In addition, we apply systematic uncertainties $δ_{sys}=0\%, 3\%, 5\%$ and we consider unpolarized and polarized electron beam. Our results show that the FCC-he is a very good perspective to probe the $\hat a_V$ and $\hat a_A$ at high-energy and high-luminosity frontier.

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arXiv2019

Feasibility at the LHC, FCC-he and CLIC for sensitivity estimates on anomalous $τ$-lepton couplings

In this paper, we present detailed studies on the feasibility at $pp$, $e^-p$ and $e^+e^-$ colliders for model-independent sensitivity estimates on the total cross-section and on the anomalous $τ^+τ^-γ$ interaction through the tau pair production channels $pp \to pτ\bar τγp$, $e^-p \to e^- τ\bar τγp$ and $e^+e^- \to e^+ τ\bar τγe^-$ at the $γ^*γ^* \to τ^+τ^-γ$ mode. Measurements of the anomalous couplings of the $τ$-lepton $\tilde{a}_τ$ and $\tilde{d}_τ$ provide an excellent opportunity to probing extensions of the Standard Model. We estimate the sensitivity at the $95\%$ Confidence Level, and we consider that the $τ$-lepton decays leptonically or semi-leptonically. We found that of the three considered colliders, the future CLIC at high energy and high luminosity should provide the best sensitivity on the dipole moments of the $τ$-lepton $\tilde a_τ= [-0.00128, 0.00105]$ and $ |\tilde{d}_τ({\rm ecm})|= 6.4394\times 10^{-18}$, which show a potential advantage compared to those from LHC and FCC-he.

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arXiv2018

The $μ^+μ^-$ collider to sensitivity estimates on the magnetic and electric dipole moments of the tau-lepton

Using the effective Lagrangian formalism, the anomalous magnetic and electric dipole moments of the tau-lepton in the $μ^{+}μ^{-} \rightarrow μ^{+}γ^{*} γ^{*} μ^{-}\rightarrow μ^{+}τ\barτμ^{-}$ process at the future muon colliders at the $\sqrt{s}=1.5, 3$ and $6$ TeV are investigated. In addition, the bounds at the $95\%$ confidence level on the dipole moments of the tau-lepton using different integrated luminosities are estimated. It is shown that the $μ^{+}μ^{-} \rightarrow μ^{+}γ^{*} γ^{*} μ^{-}\rightarrow μ^{+}τ\barτμ^{-}$ process leads to a remarkable improvement in the existing experimental bounds on the anomalous magnetic and electric dipole moments of the tau-lepton.

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arXiv2017

Improved sensitivity on the electromagnetic dipole moments of the top quark in $γγ$, $γγ^$ and $γ^γ^*$ collisions at the CLIC

We realize a phenomenological study to examine the sensitivity on the magnetic moment and electric dipole moment of the top quark through the processes $γγ\rightarrow t \bar{t}$, $e γ\rightarrow e γ^{*} γ\rightarrow e t \bar{t}$ and $e^{-} e^{+}\rightarrow e^{-} γ^{*} γ^{*} e^{+} \rightarrow e^{-} t \bar{t}e^{+}$ at the CLIC. We find that with a center-of-mass energy of the CLIC-1.4$\hspace{0.8mm}TeV$, integrated luminosity of ${\cal L}=1500\hspace{0.8mm}fb^{-1}$ and CLIC-3$\hspace{1mm}TeV$, integrated luminosity of ${\cal L}=2000\hspace{0.8mm}fb^{-1}$ with systematic uncertainties of $δ_{sys}=0, 5, 10\hspace{1mm}\%$ at the $95\%\hspace{1mm}C. L.$, it is possible the CLIC may put limits on the electromagnetic dipole moments of the top quark $\hat a_V$ and $\hat a_A$ with a sensitivity of ${\cal O}(10^{-3}-10^{-2})$. Therefore, we show that the sensitivity with the CLIC data is much greater than that for the LHC data.

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arXiv2017

Probing the electromagnetic dipole moments of the tau-neutrino in the $U(1)_{B-L}$ model at the ILC and CLIC energies

In this work we study the sensitivity on the anomalous magnetic and electric dipole moments of the tau-neutrino in the framework of the $SU(2)_L\times U(1)_Y\times U(1)_{B-L}$ electroweak model at future $e^+e^-$ linear colliders as the ILC and CLIC. For our study we consider the process $e^{+}e^{-}\rightarrow ( Z, Z', γ) \to ν_τ\bar ν_τγ$. For center-of-mass energies of $\sqrt{s}=1000-3000\hspace{0.8mm}GeV$ and integrated luminosities of ${\cal L}=500-2000\hspace{0.8mm}fb^{-1}$, we derive $95 \% \hspace{1mm}$ C.L. limits on the dipole moments $|μ_{ν_τ}(μ_B)| \leq 6.28 \times 10^{-9}$ and $|d_{ν_τ}(e cm)| \leq 1.21 \times 10^{-21}$ improve the existing limits by two or three orders of magnitude. Our study complements other studies on the dipole moments of the tau-neutrino at hadron and $e^+e^-$ colliders.

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arXiv2017

Stellar energy loss rates in the pair-annihilation process beyond the standard model

We calculate the stellar energy loss due to neutrino-pair production in $e^+e^-$ annihilation in the context of a 331 model, a left-right symmetric model and a simplest little Higgs model in a way that can be used in supernova calculations. We also present some simple estimates which show that such process can act as an efficient energy loss mechanism in the shocked supernova core. We find that the stellar energy loss is almost independent on the parameters of the models in the allowed range for these parameters. This work complements other studies on the stellar energy loss rate in $e^+e^-$ annihilation.

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arXiv2015

Improved bounds on the dipole moments of the tau-neutrino at high-energy $γ^* e^-$ and $γ^* γ^*$ collisions: ILC and CLIC

In this work we study the potential of the processes $e^+e^- \to e^+γ^* e^- \to e^+τ\barν_τν_e $ and $e^+e^- \to e^+γ^* γ^* e^- \to e^+ν_τ\barν_τe^- $ at a future high-energy and high-luminosity linear electron positron collider, such as the ILC and CLIC to study the sensibility on the anomalous magnetic and electric dipole moments of the tau-neutrino. For integrated luminosity of 590\hspace{1mm}$fb^{-1}$ and center-of-mass energy of 3\hspace{1mm}$TeV$, we derive $95 \% \hspace{1mm}C. L.$ limits on the dipole moments: $μ_{ν_τ}\leq 1.44 \times 10^{-6}μ_B$ and $d_{ν_τ}\leq 2.78 \times 10^{-17}\hspace{1mm} e\hspace{0.5mm} cm$ in the $γ^* e^-$ collision mode and of $μ_{ν_τ}\leq 3.4 \times 10^{-7}μ_B$ and $d_{ν_τ}\leq 6.56 \times 10^{-18}\hspace{1mm} e\hspace{0.5mm}cm$ with the $γ^*γ^*$ collision mode, improving the existing limits.

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arXiv2004

Limits on the Dipole Moments of the $τ$-Lepton via the Process $e^{+}e^{-}\to τ^+ τ^- γin a Left-Right Symmetric Model

Limits on the anomalous magnetic moment and the electric dipole moment of the $τ$ lepton are calculated through the reaction $e^{+}e^{-}\to τ^+ τ^- γ$ at the $Z_1$-pole and in the framework of a left-right symmetric model. The results are based on the recent data reported by the L3 Collaboration at CERN LEP. Due to the stringent limit of the model mixing angle $ϕ$, the effect of this angle on the dipole moments is quite small.

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arXiv2003

Higgs Pair-Production in the Standard Model at Next Generation Linear $e^+e^-$ Colliders

We study the Higgs pair-production in the Standard Model of the strong and electroweak interactions at future $e^{+}e^{-}$ collider energies, with the reaction $e^{+}e^{-}\to t \bar t HH$. We evaluated the total cross section of $t\bar tHH$ and calculate the number total of events considering the complete set of Feynman diagrams at tree-level. The numerical computation is done for the energy which is expected to be available at a possible Next Linear $e^{+}e^{-}$ Collider: with center-of-mass energy $800, 1600$ $GeV$ and luminosity 1000 $fb^{-1}$.

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arXiv2003

Pair Production and Angular Distribution of Helicity Flipped Neutrinos in a Left-Right Symmetric Model

We assume that a massive Dirac neutrino is characteized by two phenomenological parameters, a magnetic moment, and a charge radius, and we calculate the cross-section of the scattering $e^+e^-\to ν\bar ν$ in a left-right symmetric model. We also analyze the angular distribution of the neutrino (antineutrino) with respect to the original direction of the electron (positron) to different state of helicity of the neutrino. We find that the favored directions for the neutrino (antineutrino) with respect to the electron (positron) is forward $(θ=0)$ and backward $(θ= π)$, and is not very probable in the perpendicular direction $(θ= \fracπ{2})$. The calculation is for $ϕ= -0.005$ and $M_{Z_2}=500$ $GeV$, parameters of the Left-Right symmetric model.

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arXiv2001

Neutron Beta Decay in a Left-Right Symmetric Model

We start from a Left-Right Symmetric Model and we analyze the beta decay of the free neutron $n\to p+e^{-}+\barν_{e}$. We applied this model to incorporate the right currents, whereby we propose an amplitude whose leptonic part contains the parameter $λ$ defined as left-right asymmetry parameter which measures the parity violation. The analysis consists of seeing how the spectrum of energy of the electrons, the total rate of decay, and the lifetime $τ$ of the neutron are affected by the left-right asymmetry parameter, besides taking into account corrections of mass, that is, $m_{e}\neq 0$, $m_{p}\neq m_{n}$, and the recoil of the proton.

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arXiv2001

Elastic neutrino-electron scattering and effective couplings $(g^{νe}_V)_{LRSM}$ and $(g^{νe}_A)_{LRSM}$ in a Left-Right symmetric model

We start from a Left-Right Symmetric Model with massive Dirac neutrinos, with an electromagnetic structure that consists of a charge radius, and we calculate the cross-section of the scattering $ν_μe^-\to ν_μe^-$. Subsequently, we calculate the simultaneous contribution of the charge radius, of the additional $Z_{2}$ heavy gauge boson and of the mixing angle $ϕ$ parameter of the model at the constants of couplings $(g^{νe}_{V})_{LRSM}$ and $(g^{νe}_{A})_{LRSM}$.

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arXiv2001

Production of the MSSM Higgs Bosons at Next Generation Linear $e^+e^-$ Colliders

% insert abstract here We study the production of the Higgs bosons predicted in the Minimal Supersymmetric extension of the Standard Model $(h^0, H^0, A^0, H^\pm)$, with the reactions $e^{+}e^{-}\to b\bar b h^0 (H^0, A^0)$, and $e^+e^-\to τ^-\bar ν_τH^+, τ^+ν_τH^-$, using the helicity formalism. We evaluate cross section of $h^0, H^0, A^0$ and $H^\pm$ in the limit when $\tanβ$ is large. The numerical computation is done considering two stages of a possible Next Linear $e^{+}e^{-}$ Collider: the first with $\sqrt{s}=500$ $GeV$ and design luminosity 50 $fb^{-1}$, and the second with $\sqrt{s}=1$ $TeV$ and luminosity 100-200 $fb^{-1}$.

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