Large and Almost Maximal Neutrino Mixing within the Type II See-Saw Mechanism

Within the type II see-saw mechanism the light neutrino mass matrix is given by a sum of a direct (or triplet) mass term and the conventional (type I) see-saw term. Both versions of the see-saw mechanism explain naturally small neutrino masses, but the type II scenario offers interesting additional possibilities to explain large or almost maximal or vanishing mixings which are discussed in this paper. We first introduce ``type II enhancement'' of neutrino mixing, where moderate cancellations between the two terms can lead to large neutrino mixing even if all individual mass matrices and terms generate small mixing. However, nearly maximal or vanishing mixings are not naturally explained in this way, unless there is a certain initial structure (symmetry) which enforces certain elements of the matrices to be identical or related in a special way. We therefore assume that the leading structure of the neutrino mass matrix is the triplet term and corresponds to zero U_{e3} and maximal theta_{23}. Small but necessary corrections are generated by the conventional see-saw term. Then we assume that one of the two terms corresponds to an extreme mixing scenario, such as bimaximal or tri-bimaximal mixing. Deviations from this scheme are introduced by the second term. One can mimic Quark-Lepton Complementarity in this way. Finally, we note that the neutrino mass matrix for tri-bimaximal mixing can be -- depending on the mass hierarchy -- written as a sum of two terms with simple structure. Their origin could be the two terms of type II see-saw.Comment: 25 pages. Comments and references added, to appear in JHE

Focus Point SUSY at the LHC Revisited

The estimation of the backgrounds for gluino signals in focus point supersymmetry is extended by including the backgrounds from the production of four third generation quarks in the analysis. We find that these backgrounds are negligible if one uses the strong selection criteria proposed in the literature (including this analysis) for heavy gluino searches. Softer selection criteria often recommended for lighter gluino searches yield backgrounds which are small but numerically significant. We have also repeated the more conventional background calculations and compared our results with the other groups. We find that the size of the total residual background estimated by different groups using different event generators and hard kinematical cuts agree approximately. In view of the theoretical uncertainties in the leading order signal and background cross sections mainly due to the choice of the QCD scale, the gluino mass reach at the LHC cannot be pinpointed. However, requiring a signal with $\rm\geq 3$ tagged b-jets (instead of the standard choice of $\rm\geq 2$) it is shown that gluino masses close to 2 TeV can be probed at the LHC for a range of reasonable choices of the QCD scale for an integrated luminosity of 300 fb$^{-1}$.Comment: 17 pages, 4 figures, minor typos correctio

Reach of the Fermilab Tevatron for minimal supergravity in the region of large scalar masses

The reach of the Fermilab Tevatron for supersymmetric matter has been calculated in the framework of the minimal supergravity model in the clean trilepton channel. Previous analyses of this channel were restricted to scalar masses m_0<= 1 TeV. We extend the analysis to large values of scalar masses m_0\sim 3.5 TeV. This includes the compelling hyperbolic branch/focus point (HB/FP) region, where the superpotential \mu parameter becomes small. In this region, assuming a 5\sigma (3\sigma) signal with 10 (25) fb^{-1} of integrated luminosity, the Tevatron reach in the trilepton channel extends up to m_{1/2}\sim 190 (270) GeV independent of \tan\beta . This corresponds to a reach in terms of the gluino mass of m_{\tg}\sim 575 (750) GeV.Comment: 11 page latex file including 6 EPS figures; several typos corrected and references adde

Sublethal doses of glyphosate in combination with leaf manganese in marandu grass production

The drift of the herbicide glyphosate can stimulate growth and/or productive yield in non-target plants, which characterizes a hormonal effect, with a momentary yellowing in new leaves, characteristic of nutritional deficiency. Thus, the objective of this work was to evaluate the hormonal effect of glyphosate application in Urochloa brizantha cv. Marandu. The produtive response, aerial (PMS ) and root (MSR), for forage was evaluated by foliar application of seven sublethal doses of equivalent acid (e.a.) to glyphosate (5.40, 10.80, 21.60, 43.20, 64, 80, 86.40 and 108.00 g e.a. ha-1) and control, in the absence and presence of manganese (1000 g ha-1), in the spray solution, in four sequential harvests, featuring a factorial scheme 8 x 2 x 4, with four repetitions. The sublethal doses of glyphosate with the addition of manganese to the spray solution reduced the herbicidal effect, with persistence of PMS during the experimental period (4 cuts). For doses without manganese added to the spray solution, there was a productive failure in the cuts 2, 3 and 4, at doses 86.40 and 108.00 g e.a. ha-1. The presence of manganese in the spray solution ensured a root dry mass superior to those without the addition of manganese, with an effect herbicide in doses equal to and above 43.60 g e.a. ha-1.A deriva do herbicida glifosato pode estimular crescimento e/ou rendimento produtivo em plantas não-alvo, caracterizando efeito hormese. Ainda, manifesta-se amarelecimento momentâneo em folhas novas, característico de deficiência nutricional. Deste modo, o trabalho teve por objetivo avaliar o efeito hormese por aplicação de glifosato em Urochloa brizantha cv. Marandu. Foi avaliada a resposta produtiva aérea (PMS) e radicular (MSR) da forrageira por aplicação foliar de sete doses subletais do equivalente ácido (e.a.) de glifosato (5,40, 10,80, 21,60, 43,20, 64,80, 86,40 e 108,00, g e.a. ha-1) e controle, sob ausência e presença de manganês (1000 g ha-1) à calda de pulverização, em quatro colheitas sequenciais, caracterizando esquema fatorial 8 x 2 x 4, com quatro repetições. As doses subletais de glifosato com adição de manganês à calda de pulverização reduziram o efeito herbicida, com persistência de PMS durante período experimental (4 cortes). Para doses sem adição de manganês à calda de pulverização, houve falência produtiva nos cortes 2, 3 e 4, para doses 86,40 e 108,00 g e.a. ha-1. A presença de manganês à calda de pulverização assegurou massa seca de raiz superior àquelas sem adição de manganês, sendo constatado efeito do herbicida nas doses igual e superiores a 43,60 g e.a. ha-1