J. Sá Borges

Extra neutral gauge boson from two versions of the 3-3-1 model in future linear colliders

Our aim is to establish some signatures of the extra gauge boson Z′, predicted in two versions of the SU(3)C×SU(3)L×U(1)X model and to show possible differences between these signatures. First, by considering the process e++e-→μ++μ-, we obtain some observables and next, by considering additional hadronic final states, we obtain lower bounds for MZ′, within 95% C.L. We also include our preliminary results concerning pp̄ and pp collisions in order to support our conclusions about the possibility to discriminate different versions of the 3-3-1 model. From our analysis we conclude that linear colliders can show a clear signature for the existence of Z′ predicted in the 3-3-1 model and also that it can discriminate the various versions.

Four leptons production in e−e+ collisions from 3–3–1 model

Abstract We study the process e − + e + → e + + e + + e − + e − for ILC and CLIC energy regimes, in the minimal 3–3–1 model framework. The main contributions, for the production of two bileptons each one decaying into two same-sign leptons, come from s-channel annihilation (via γ , Z and Z ′ ) and t-channel electron exchange. We evaluate the number of events for an extra neutral gauge boson mass M Z ′ in the range 1 TeV to 3 TeV. We compare some distributions from 3–3–1 model with the Standard Model background in order to extract a possible signature of the contribution of bilepton and Z ′ for the process. From our analysis we conclude that our results give clear signals for physics beyond the Standard Model in e − e + colliders.

Charged bilepton pair production at LHC including exotic quark contribution

Abstract The production of W + W − pair in hadron colliders was calculated up to loop corrections by some authors in the Electroweak Standard Model (SM) framework. This production was also calculated, at the tree level, in some extensions of the SM such as the vector singlet, the fermion mirror fermion and the vector doublet models by considering the contributions of new neutral gauge bosons and exotic fermions. The obtained results for e + e − and pp collisions pointed out that the new physics contributions are quite important. This motivates us to calculate the production of a more massive charged gauge boson predicted by the SU ( 3 ) C × SU ( 3 ) L × U ( 1 ) X model (3-3-1 model). Thus, the aim of the present paper is to analyze the role played by of the extra gauge boson Z ′ and of the exotic quarks, predicted in the minimal version of the 3-3-1 model, by considering the inclusive production of a pair of bileptons ( V ± ) in the reaction p + p → V + + V − + X , at the Large Hadron Collider (LHC) energies. Our results show that the correct energy behavior of the elementary cross section follows from the balance between the contributions of the extra neutral gauge boson with those from the exotic quarks. The extra neutral gauge boson induces flavor-changing neutral currents (FCNC) at tree level, and we have introduced the ordinary quark mixing matrices for the model when the first family transforms differently to the other two with respect to SU ( 3 ) L . We obtain a huge number of heavy bilepton pairs produced for two different values of the center of mass energy of the LHC.

Nucleon and delta sigma-terms

We discuss some phenomenological applications of an infrared finite gluon propagator characterized by a dynamically generated gluon mass. In particular we compute the effect of the dynamical gluon mass on pp and p̄p diffractive scattering. We also show how the data on γp photoproduction and hadronic γγ reactions can be derived from the pp and p̄p forward scattering amplitudes by assuming vector meson dominance and the additive quark model.

Symmetry breaking patterns of the 3-3-1 model at finite temperature

We consider the minimal version of an extension of the standard electroweak model based on the

Nucleon Finite Volume Effect and Nuclear Matter Properties in a Relativistic Mean-Field Theory

SU(3)_c \times SU(3)_L \times U(1)_X

Unitarity corrections to a low-energy pion–nucleon scattering amplitude

SU(3)c×SU(3)L×U(1)X gauge symmetry (the 3-3-1 model). We analyze the most general potential constructed from three scalars in the triplet representation of