arXiv subjects

J. L. Diaz Cruz

Publications and source records attributed to J. L. Diaz Cruz.

4 recordsLinked to original sources

arXiv2003

Probing the charged Higgs quantum numbers through the decay H^+ -> W^+ h^0

The vertex H^+_αW^-h^0_β, involving the gauge boson W^+- and the charged (H^+-_α) and neutral Higgs bosons (h^0_β), arises within the context of many extensions of the SM, and it can be used to probe the quantum numbers of the Higgs multiplet. After presenting a general discusion for the expected form of this vertex with arbitrary Higgs representations, we discuss its strength for several specific models, which include: i) the Two-Higgs Doublet Model (THDM), both the generic and the SUSY case, and ii) models with additional Higgs triplets, including both SUSY and non-SUSY cases. We find that in these models, there are regions of parameters where the decay H^+_α-> W^+ h^0_β, is kinematically allowed, and reaches Branching Ratios (BR) that may be detectable, thus allowing to test the properties of the Higgs sector.

hep-ph↗

arXiv2002

Present and Future Electroweak Precision Measurements and the Indirect Determination of the Mass of the Higgs Boson

We discuss the experimental and theoretical uncertainties on precision electroweak observables and their relationship to the indirect constraints on the Higgs-boson mass, $\MH$, in the Standard Model (SM). The critical experimental measurements ($\MW$, $\sweff$, $\mt$, ...) are evaluated in terms of their present uncertainties and their prospects for improved precision at future colliders, and their contribution to the constraints on $\MH$. In addition, the current uncertainties of the theoretical predictions for $\MW$ and $\sweff$ due to missing higher order corrections are estimated and expectations and necessary theoretical improvements for future colliders are explored. The constraints from rare B decays are also discussed. Analysis of the present experimental and theoretical precisions yield a current upper bound on $\MH$ of $\sim 200$ GeV. Including anticipated improvements corresponding to the prospective situation at future colliders (Tevatron Run II, LHC, LC/GigaZ), we find a relative precision of about 25% to 8% (or better) is achievable in the indirect determination of $\MH$.

hep-ph↗

arXiv2000

Testing models with non-minimal Higgs sector through the decay t->q+WZ

We study the contribution of charged Higgs boson to the rare decay of the top quark t->q+WZ (q=d,s,b) in models with Higgs sector that includes doublets and triplets. Higgs doublets are needed to couple charged Higgs with quarks, whereas the Higgs triplets are required to generate the non-standard vertex HWZ at tree-level. It is found that within a model that respect the custodial SU(2) symmetry and avoids flavour changing neutral currents by imposing discrete symmetries, the decay mode t->b+WZ, can reach a branching ratio of order 0.0178, whereas the decay modes t->(d,s)+WZ, can reach a similar branching ratio in models where flavour changing neutral currents are suppressed by flavour symmetries.

hep-ph↗

arXiv1995

Low-energy effects of Charged Higgs with general Yukawa couplings

We study a model with two Higgs doublets where FCNC are allowed at tree-level. In this model, the interactions of charged Higgs with fermions ($H^\pm f \bar{f'}$), include a term that is not proportional to the fermion masses, which we constraint using the following low-energy processes: i) tau decays ($τ\to ν_τ eν_e, ν_τμν_μ, ν_τπ$), ii) leptonic decays of pseudoscalar mesons ($π, K \to \ellν_{\ell}$) and iii) semileptonic b-decays. With these constraints it is possible to make predictions; we illustrate this by presenting the rates for the (FCNC) decay $c\to u+γ$, the (second class-current) decay $τ\to ν_τ+ ηπ$, and also the theoretical value of the neutron life-time.

hep-ph↗