Fine-tuning in gauge mediated supersymmetry breaking models and induced top Yukawa coupling

It is shown that fine-tuning of the Higgs parameters stronger than a few % is required at the best in the models with gauge mediated supersymmetry breaking. With the aim of solving this problem, we consider a new type of models in which the top Yukawa coupling is induced at TeV scale through mass mixing with unknown matter fields. Then it is found that the fine-tuning problem can be eliminated essentially. We discuss some phenomenological features of this model and also consider the extension to the next-to-minimal models.Comment: 14 pages, 9 Postscript figures, uses revtex4.sty, Some comments and a reference added, to appear in Phys. Rev.

Induced top Yukawa coupling and suppressed Higgs mass parameters

In the scenarios with heavy top squarks, mass parameters of the Higgs field must be fine-tuned due to a large logarithmic correction to the soft scalar mass. We consider a new possibility that the top Yukawa coupling is small above TeV scale. The large top mass is induced from strong Yukawa interaction of the Higgs with another gauge sector, in which supersymmetry breaking parameters are given to be small. Then it is found that the logarithmic correction to the Higgs soft scalar mass is suppressed in spite of the strong coupling and the fine-tuning is ameliorated. We propose an explicit model coupled to a superconformal gauge theory which realizes the above situation.Comment: RevTeX4 style, 10 pages, 3 figure

The magnetic structure of the intermelallic compounds in the cubic Laves phase (C15) crystal

Magnetic structure of intermetallic compounds of rare earth and 3d transition metal with the C15 structure is studied on the basis of the classical Heisenberg model. By making use of the Lyons-Kaplan method, magnetic phase diagram is calculated with respect to the states with the modulation wave vector Q equivalent to [0,0,0] to obtain seven types of spin structure, and their stability is compared with screw structures of Q parallel with [0,0,1], [1,1,0] and [1,1,1]. The stable region of the Q = [0,0,0] states is limited most drastically by the modulation of Q ∥ [1,1,0].Article信州大学理学部紀要 30(1): 7-23(1995)departmental bulletin pape

Exponents of 2-multiarrangements and multiplicity lattices

We introduce a concept of multiplicity lattices of 2-multiarrangements, determine the combinatorics and geometry of that lattice, and give a criterion and method to construct a basis for derivation modules effectively.Comment: 14 page

Suppressed supersymmetry breaking terms in the Higgs sector

We study the little hierarchy between mass parameters in the Higgs sector and other SUSY breaking masses. This type of spectrum can relieve the fine-tuning problem in the MSSM Higgs sector. Our scenario can be realized by superconformal dynamics. The spectrum in our scenario has significant implications in other phenomenological aspects like the relic abundance of the lightest neutralino and relaxation of the unbounded-from-below constraints.Comment: 14 pages, late

Influência da temperatura no controle de fungos causadores e podridões de melão.

Atualmente os patógenos causadores de doenças na pós-colheita são controlados com agroquímicos, de forma indiscriminada e excessiva provocando a contaminação química da fruta. Com a tendência mundial de redução do uso desses agroquímicos na fase de pós-colheita há uma demanda por compostos e estratégias alternativas no controle de doenças fúngicas das frutas. O objetivo desse trabalho foi determinar os binômios de tempos e temperaturas letais para o fungo Fusarium pallidoroseum, causador de doenças na pós-colheita de melão, para apoiar estudos sobre a utilização do tratamento térmico por aspersão de água quente com escovação, como uma alternativa ao uso de fungicidas. Discos de micélio foram colocados em bolsas de gaze estéril e dispostos no interior de um balão de 3 bocas, com água a temperatura desejada, com termômetro e um agitador. Após o tempo de tratamento os micélios colocados em água fria a 20 °C e plaqueados em meio BDA e incubados à 25°C para avaliação diária do crescimento micelial. O F. pallidoroseum apresentou elevada termo resistência mostrando-se os binômios: 52°C/540s; 54°C/300s; 56°C/180s; 58°C/60s; 60°C/20s e 62°C/15s. Pelo gráfico de log do tempo x temperatura é possivel identificar as combinações de tempos e temperaturas capazes de controlar o fungo. Curtos tempos de exposição em temperaturas mais elevadas mostraram-se efetivos no controle do fungo, demonstrando que o uso do tratamento hidrotérmico por aspersão de água quente por curto intervalo de tempo é um método potencial de controle alternativo à utilização de fungicidas no tratamento pós-colheita de melão