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M. C. Rodriguez

Publications and source records attributed to M. C. Rodriguez.

At least 37 records · Page 2Linked to original sources

The Minimal Supersymmetric Standard Model (MSSM) and General Singlet Extensions of the MSSM (GSEMSSM), a short review

In this lectures, we give a review about the Minimal Supersymmetric Standard Model (MSSM) and the General Singlet Extensions of the MSSM (GSEMSSM). We, first introduce the minimal set of fields to built both models. Then we introduce their superfields and using them we build the lagrangian of those models in the superspace formalism. We show how to get the mass spectrum of those model in the $R$-parity scenarios and we also show how to get some Feynman Rules with the Gauge Bosons.

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Supersymmetric $U(1)_{Y^{\prime}}\otimes U(1)_{B-L}$ extension of the standard model

We build a supersymmetric version with $SU(3)_C\otimes SU(2)_L\otimes U(1)_{Y^\prime}\otimes U(1)_{B-L}$ gauge symmetry, where $Y^\prime$ is a new charge and $B$ and $L$ are the usual baryonic and leptonic numbers. The model has three right-handed neutrinos with identical $B-L$ charges, and can accommodate all fermion masses at the tree level. In particular, the type-I seesaw mechanism is implemented for the generation of the active neutrino masses. We obtain the mass spectra of all sectors and for the scalar one we also give the flat directions allowed by the model.

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Flat Directions and Leptogenesis in a "New" $μν$SSM

In this paper, we give a brief review of the Minimal Supersymmetric Standard Model (MSSM) and "$μ$ from $ν$" Supersymmetric Standard Model ($μν$SSM). Then we propose a generalization of $μν$SSM in order to explain the recent ATLAS, CMS and LHCb results. This "new" $μν$SSM generalizes the superpotential $W_{suppot}$ of $μν$SSM by including two terms that generate a mixing among leptons, gauginos and higgsinos while keeping the charginos and neutralinos masses unchanged. Also, it is potentially interesting for cosmological applications as it displays flat directions of the superpotential and a viable leptogenesis mechanism.

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Supersymmetric reduced minimal 3-3-1 model

We build an supersymmetric version of the minimal 3-3-1 model with just two Higgs triplets using the superfield formalism. We study the mass spectrum of all particles in concordance with the experimental bounds. At the tree level, the masses of charged gauge bosons are the same as those of charged Higgs bosons. We also show that the electron, muon and their neutrinos as well as down and strange quarks gain mass through the loop correction. The narrow constraint on the ratio t_w = \frac{w}{w^\prime} is given by studying the new invisible decay mode of the Z boson.

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Photino and Gluino Production in SQED and SQCD

This review starts out with a brief history of the photino-gluino phenomenology. Next, it describes difficulties encountered in the construction of Feynman amplitudes when dealing with Majorana fermions and outlines a procedure that circumvents this difficulty by means of a prescription based on a well-defined fermion flow without explicit charge-conjugation matrices at the vertex equations. Finally, as an illustration, it calculates the cross section for the production of photinos and gluinos.

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Neutrino Masses in Supersymmetric Economical SU(3)_C X SU(3)_L X U(1)_X Model

The R-symmetry formalism is applied for the supersymmetric economical SU(3)_C X SU(3)_L X U(1)_X (3-3-1) model. The generalization of the minimal supersymmetric standard model relation among R-parity, spin and matter parity is derived, and discrete symmetries for the proton stability in this model are imposed. We show that in such a case it is able to give leptons masses at just the tree level. A simple mechanism for the mass generation of the neutrinos is explored. With the new R-parity, the neutral fermions get mass matrix with two distinct sectors: one light which is identified with neutrino mass matrix, another heavy one which is identified with neutralinos one. The similar situation exists in the charged fermion sector. Some phenomenological consequences such as proton stability, neutrinoless double beta decays are discussed.

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Gluino production in ultrarelativistic heavy ion collisions and nuclear shadowing

In this article we investigate the influence of nuclear effects in the production of gluinos in nuclear collisions at the LHC, and estimate the transverse momentum dependence of the nuclear ratios $R_{pA} = {\frac{dσ(pA)}{dy d^2 p_T}} / A {\frac{dσ(pp)}{dy d^2 p_T}}$ and $R_{AA} = {\frac{dσ(AA)}{dy d^2 p_T}} / A^2 {\frac{dσ(pp)}{dy d^2 p_T}}$. We demonstrate that depending on the magnitude of the nuclear effects, the production of gluinos could be enhanced, compared to proton-proton collisions. The study of these observables can be useful to determine the magnitude of the shadowing and antishadowing effects in the nuclear gluon distribution. Moreover, we test different SPS scenarios, corresponding to different soft SUSY breaking mechanisms, and find that the nuclear ratios are strongly dependent on that choice.

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Mass Spectrum in the Minimal Supersymmetric 3-3-1 model

We consider the minimal supersymmetric extension of the 3-3-1 model. We study the mass spectra of this model in the fermionic and gauge bosons sectors without the antisextet. We also present some phenomenological consequences of this model at colliders such as Large Hadron Collider (LHC) and International Linear Collider(ILC).

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History of Supersymmetric Extensions of the Standard Model

We recall the many obstacles which seemed, long ago, to prevent supersymmetry from possibly being a fundamental symmetry of Nature. We also present their solutions, leading to the construction of the supersymmetric extensions of the Standard Model. Finally we discuss briefly the early experimental searches for Supersymmetry.

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Gluino production in some supersymmetric models at the LHC

In this article we review the mechanisms in several supersymmetric models for producing gluinos at the LHC and its potential for discovering them. We focus on the MSSM and its left-right extensions. We study in detail the strong sector of both models. Moreover, we obtain the total cross section and differential distributions. We also make an analysis of their uncertainties, such as the gluino and squark masses, which are related to the soft SUSY breaking parameters.

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Investigating gluino production at the LHC

Gluinos are expected to be one of the most massive sparticles (supersymmetric partners of usual particles) which constitute the Minimal Supersymmetric Standard Model (MSSM). The gluinos are the partners of the gluons and they are color octet fermions, due this fact they can not mix with the other particles. Therefore in several scenarios, given at SPS convention, they are the most massive particles and their nature is a Majorana fermion. Therefore their production is only feasible at a very energetic machine such as the Large Hadron Collider (LHC). Being the fermion partners of the gluons, their role and interactions are directly related with the properties of the supersymmetric QCD (sQCD). We review the mechanisms for producing gluinos at the LHC and investigate the total cross section and differential distributions, making an analysis of their uncertainties, such as the gluino and squark masses, as obtained in several scenarios, commenting on the possibilities of discriminating among them.

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Radiative Mechanism to Light Fermion Masses in the MSSM

In a previous work we have showed that the ${\cal Z}_{2}^{\prime}$ Symmetry, imply that the light fermions, the electron and the quarks, $u,d$ and $s$, get their masses only at one loop level. Here, we considere the more general hypothesis for flavour mixing in the sfermion sector in the MSSM. Then, we present our results to the masses of these light fermions and as a final result we can explain why the $s$ quark is heavier than the $u,d$ quarks. This mechanism is in agrement with the experimental constraint on the sfermion's masses values.

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Double Chargino Production in $e^{-}e^{-}$ scattering

We point out the production of the charginos and neutralinos in electron-electron process in several supersymmetric models, in order to show that the International Linear Collider can discover double charged charginos if these particles really exist in nature.

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Supersymmetric economical 3-3-1 model

The supersymmetric extension of the economical 3-3-1 model is presented. The constraint equations and the gauge boson identification establish a relation between the vacuum expectation values (VEVs) at the top and bottom elements of the Higgs triplet $χ$ and its supersymmetric counterpart $χ^\prime$. Because of this relation, the exact diagonalization of neutral gauge boson sector has been performed. The gauge bosons and their associated Goldstone ones mix in the same way as in non-supersymmetric version. This is also correct in the case of gauginos. The eigenvalues and eigenstates in the Higgs sector are derived. The model contains a heavy neutral Higgs boson with mass equal to those of the neutral non-Hermitian gauge boson $X^0$ and a charged scalar with mass equal to those of the $W$ boson in the standard model, i. e. $ m_{\varrho_1} = m_W$. This result is in good agreement with the present estimation: $m_{H^\pm} > 79.3$ GeV, CL= 95 %. We also show that the boson sector and the fermion sector gain masses in the same way as in the non-supersymmetric case.

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A supersymmetric 3-4-1 model

We build the complete supersymmetric version of a 3-4-1 gauge model using the superfield formalism. We point out that a discrete symmetry, similar to the R-symmetry in the minimal supersymmetric standard model, is possible to be defined in this model. Hence we have both R-conserving and R-violating possibilities. We also discuss some phenomenological results coming from this model.

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Scalar Sector in the Minimal Supersymmetric 3-3-1 model

We consider the minimal supersymmetric extension of the 3-3-1 model and we study the mass spectra in the scalar sector of this model without the anti-sextet. We show that all our lighest scalars are in agreement with the experimental limits.

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Neutrino Masses in the Supersymmetric SU(3)_C X SU(3)_L X U(1)_X Model with right-handed neutrinos

The R-symmetry formalism is applied for the supersymmetric SU(3)_C X SU(3)_L X U(1)_X (3-3-1) model with right-handed neutrinos. For this kind of models, we study generalization of the MSSM relation among R-parity, spin and matter-parity. Discrete symmetries for the proton stable in this model are imposed, and we show that in such a case it is able to give leptons masses at only the tree level contributions required. A simple mechanism for the mass generation of the neutrinos is explored. We show that at the low-energy effective theory, neutrino spectrum contains three Dirac fermions, one massless and two degenerate in mass. At the energy-level where the mixing among them with neutralinos turned on, neutrinos obtain Majorana masses and correct the low-energy effective result which naturally gives rise to an inverted hierarchy mass pattern. This mass spectrum can fit the current data with minor fine-tuning. Consistent values for masses of the charged leptons are also given. In this model, the MSSM neutralinos and charginos can be explicitly identified in terms of the new constraints on masses which is not as in a supersymmetric version of the minimal 3-3-1 model.

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