Stop Decay with LSP Gravitino in the final state: t~1→G~ W b\tilde{t}_1\to\widetilde{G}\,W\,b

In MSSM scenarios where the gravitino is the lightest supersymmetric particle (LSP), and therefore a viable dark matter candidate, the stop $\tilde{t}_1$ could be the next-to-lightest superpartner (NLSP). For a mass spectrum satisfying: $m_{\widetilde{G}}+m_t>m_{\tilde{t}_1}>m_{\widetilde{G}}+m_b+m_W$, the stop decay is dominated by the 3-body mode $\tilde{t}_1\rightarrow b\,W\,\tilde{G}$. We calculate the stop life-time, including the full contributions from top, sbottom and chargino as intermediate states. We also evaluate the stop lifetime for the case when the gravitino can be approximated by the goldstino state. Our analytical results are conveniently expressed using an expansion in terms of the intermediate state mass, which helps to identify the massless limit. In the region of low gravitino mass ($m_{\widetilde{G}}\ll m_{\tilde{t}_1}$) the results obtained using the gravitino and goldstino cases turns out to be similar, as expected. However for higher gravitino masses $m_{\widetilde{G}} \lesssim m_{\tilde{t}_1}$ the results for the lifetime could show a difference of O(100)\%

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.Comment: Typeset using REVTEX and EPSF, 5 pag, 2 figure

An effective lagrangian description of charged Higgs decays H^+ -> Wg, WZ and Wh

Charged Higgs decays are discussed within an effective lagrangian extension of the two-higgs doublet model, assuming new physics appearing in the Higgs sector of this model. Low energy constrains are used to imposse bounds on certain dimension -six operators that describe the modified charged Higgs interactions. These bounds are used then to study the decays H^+ -> Wg, WZ and Wh, which can have branching ratios of order 10^-5, 10^-1 and O(1), respectively; thse modes are thus sensitive probes of the symmetries of the Higgs sector that could be tested at future colliders.Comment: 15 pages, 3 figure

Indice General

[Indice General], Libreta No. 6, Jurisprudenciahttps://ecollections.law.fiu.edu/diaz-cruz-index/1076/thumbnail.jp

Competencia

Competencia. Arts. 51 al 115 de la Ley E.C. [Ley de Enjuiciamiento Civil]https://ecollections.law.fiu.edu/diaz-cruz-index/1039/thumbnail.jp

Declarativos

Declarativos. ART. 480 al 522 de la Ley de E.C. [Ley de Enjuiciamiento Civil]https://ecollections.law.fiu.edu/diaz-cruz-index/1034/thumbnail.jp