Detection of Charged MSSM Higgs Bosons at CERN LEP-II and NLC

We study the possibility of detecting the charged Higgs bosons predicted in the Minimal Supersymmetric Standard Model $(H^\pm)$, with the reactions $e^{+}e^{-}\to \tau^-\bar \nu_{\tau}H^+, \tau^+\nu_\tau H^-$, using the helicity formalism. We analyze the region of parameter space $(m_{A^0}-\tan\beta)$ where $H^\pm$ could be detected in the limit when $\tan\beta$ is large. The numerical computation is done for the energie which is expected to be available at LEP-II ($\sqrt{s}=200$ GeV) and for a possible Next Linear $e^{+}e^{-}$ Collider ($\sqrt{s}=500$ GeV).Comment: Latex file and 5 figure

Majorana neutrino decay in an Effective Approach

The search strategy or the finding of new effects for heavy neutrinos often relies on their different decay channels to detectable particles. In particular in this work we study the decay of a Majorana neutrino with interactions obtained from an effective general theory modeling new physics at the scale $\Lambda$. The results obtained are general because they are based in an effective theory and not in specific models. We are interested in relatively light heavy Majorana neutrinos, with masses lower than the $W$ mass ($m_N<m_W$). This mass range simplifies the study by reducing the possible decay modes. Moreover, we found that for $\Lambda\sim 1$ T$e$V, the neutrino plus photon channel could give explanation to different observations: we analyze the potentiality of the studied interactions to explain some neutrino-related problems like the MiniBooNE and SHALON anomalies. We show in different figures the dominant branching ratios and the decay length of the Majorana neutrino in this approach. This kind of heavy neutral leptons could be searched for in the LHC with the use of displaced vertices techniques. \Comment: 15 page, 5 figure

Pairs-Production of Higgs in Association with Bottom Quarks Pairs at e+e−e^+e^- Colliders

In a previous paper, we studied the Higgs pair production in the standard model with the reaction $e^{+}e^{-}\to t \bar t HH$. Based on this, we study the Higgs pair production via $e^{+}e^{-}\to b \bar b HH$. We evaluate the total cross section of $b\bar bHH$ and calculate the number total of events considering the complete set of Feynman diagrams at tree-level, and compare this process with the process $e^{+}e^{-}\to t \bar t HH$. The numerical computation is done for the energy which is expected to be available at a possible Next Linear $e^{+}e^{-}$ Collider with a center-of-mass energy $800, 1000, 1600$ $GeV$ and luminosity 1000 $fb^{-1}$.Comment: 12 pages, 6 figure