[en] We present results on the determination of the observable ratio R BR(H⁺ → τ⁺ν^-)/BR(H⁺ → t(bar b)) of charged Higgs boson decay rates as a discriminant quantity between Supersymmetric and non-Supersymmetric models. Simulation of measurements of this quantity through the analysis of the charged Higgs production process gb → tbH⁺ and relative backgrounds in the two above decay channels has been performed in the context of ATLAS. A ∼ 12-14% accuracy on R can be achieved for tan β = 50, m_H^±) = 300-500 GeV and after an integrated luminosity of 300 fb^-1. With this precision measurement, the Large Hadron Collider (LHC) can easily discriminate between models for the two above scenarios, so long as tan β > 20

[en] Good behaviour of zinc against atmospheric corrosion has leaded this material to be widely used, mainly for protection of steel. For this reason since approximately 50 years it have been making systematic studied in order to understand the mechanisms of its interaction with the atmosphere and nowadays it continues being object of intensive research. In this paper a review of the state-of-the-art in the knowledge of atmospheric corrosion of zinc is presented, when it is exposed in both outdoor and indoor atmospheres. (Author) 94 refs

[en] We study the Higgs-boson decays h⁰→bb-bar, h⁰→γγ and h⁰→γZ within the framework of the two Higgs doublet model (THDM) in the context of the decoupling regime, together with tree level unitarity constraints. We show that when the light CP-even Higgs boson of the THDM mimics the Standard Model Higgs boson, not only the one-loop effects to h⁰→{γγ,γZ} but also the one-loop contribution to h⁰→bb-bar can be used to distinguish between THDM and SM. The size of the quantum effects in h⁰→bb-bar are of the same order as in h⁰→{γγ,γZ} and can reach 25% in both cases

[en] A detailed analysis of the top-quark/squark quantum corrections to the lightest CP-even Higgs boson (h⁰) self-couplings is presented in the MSSM. By considering the leading one-loop Yukawa-coupling contributions of O (m_t⁴), we discuss the decoupling behavior of these corrections when the top squarks are heavy compared to the electroweak scale. As shown analytically and numerically, the large corrections can almost completely be absorbed into the h⁰-boson mass. Our conclusion is that the h⁰ self-couplings remain similar to the coupling of the SM Higgs boson for the heavy top-squark sector. (orig.)

[en] Adetailed study of top-quark polarizations and tt^- charge asymmetries, induced by top-squark-pair production at the LHC and the subsequent decays t → tχ₁⁰, is performed within the effective description of squark interactions, which includes the effective Yukawa couplings and another logarithmic term encoding the supersymmetry breaking. This effective approach is more suitable for its introduction into Monte-Carlo simulations and we make use of its implementation in MadGraph in order to investigate the possibilities of the charge asymmetry A_C, measured at the LHC and consistent with SM expectations, to discriminate between different SUSY scenarios and analyze the implications of these scenarios in the top polarizations and related observables. (orig.)

[en] Flavour-changing effects originating from the exchange of scalar particles in the processes e⁺e^-→H^xb anti s,H^x anti bs, with H^x≡h⁰,H⁰,A⁰, are investigated in the minimal supersymmetric standard model with non-minimal flavour violation at the one-loop level. The dominating SUSY-QCD contributions with squark-gluino loops are calculated and discussed. We consider the SUSY scenario with non-minimal flavour mixing in the down-type squark-mass matrix. The flavour-changing cross sections are derived, and we discuss the dependence on the MSSM parameters and the strength of flavour mixing. The values for the cross section can reach 10^-4 pb for the production of the heavy Higgs boson H⁰ or A⁰, and only 10^-7 pb for the light Higgs boson h⁰. Non-decoupling behaviour occurs for both h⁰,H⁰ production in the case of a common heavy SUSY mass scale. (orig.)

[en] The leading corrections to electroweak precision observables in the MSSM with non-minimal flavor violation (NMFV) are calculated and the effects on M_W and sin ²θ_eff are analyzed. The corrections are obtained by evaluating the full one-loop contributions from the third and second generation scalar quarks, including the mixing in the scalar top and charm, as well as in the scalar bottom and strange sector. Furthermore the leading corrections to the mass of the lightest MSSM Higgs-boson, m_h, is obtained. The electroweak one-loop contribution to M_W can amount up to 140 MeV and up to 70 x 10 ^-5 for sin ²_eff, allowing one to set limits on the NMFV parameters. The corrections for m_h are not significant for moderate generation mixing. (orig.)

[en] Expressions for SO(4) invariant euclidean QCD generating functionals are introduced which should produce non-vanishing gluon condensates. Their investigation is started here by initially considering the loop expansion of the corresponding effective action searching for a description differing from the usual perturbation theory. At this level, we consider special free propagators showing a sort or off-diagonal long range order. The calculation of the polarization tensor leads to a gluon mass term which is proportional to the squared root of the also finite value for < G²>. The summation of all the one-loop contributions to the energy having only mass insertions, indicates the spontaneous generation of the condensate from the perturbative grounds state in a way resembling the similar effect in the case of the chromomagnetic field models. This initial inspection suggests the need for a closer investigation which will be considered elsewhere. (author). 22 refs

[en] We study the heavy Higgs sector of the MSSM composed of the H^± H⁰ and A⁰ particles in the so-called decoupling limit where m_A⁰>>m_Z. By integrating out these heavy Higgs particles to one-loop, we compute the effective action for the electroweak gauge bosons and find out that, in the decoupling limit, all the heavy Higgs effects can be absorbed into redefinitions of the standard model electroweak parameters. This demonstrates explicitely that the decoupling theorem works for the heavy MSSM Higgs particles. This is also compared with the paradigmatic and different case of the standard model heavy Higgs particle. Finally, this work together with our two previous works, complete the demonstration that all the non-standard particles in the MSSM, namely, squarks, sleptons, charginos, neutralinos and the heavy Higgs particles, decouple to one-loop from the low energy electroweak gauge boson physics. (orig.)

[en] In the framework of the minimal supersymmetric standard model we compute the one-loop effective action for the electroweak bosons obtained after integrating out the different sleptons, squarks, neutralinos and charginos, and present the result in terms of the physical sparticle masses. In addition we study the asymptotic behavior of the two-, three- and four-point Green's functions with external electroweak bosons in the limit where the physical sparticle masses are very large in comparison with the electroweak scale. We find that in this limit all the effects produced by the supersymmetric particles can either be absorbed in the standard model parameters and gauge boson wave functions, or else they are suppressed by inverse powers of the supersymmetric particle masses. This work, therefore, completes the proof of decoupling of the heavy supersymmetric particles from the standard ones in the electroweak boson effective action and in the sense of the Appelquist-Carazzone theorem; we started this proof in a previous work. From the point of view of effective field theories this work can be seen as a (partial) proof that the SM can indeed be obtained from the MSSM as the quantum low-energy effective theory of the latter when the SUSY spectra are much heavier than the electroweak scale. (orig.)