A mass formula for light mesons from a potential model

The quark dynamics inside light mesons, except pseudoscalar ones, can be quite well described by a spinless Salpeter equation supplemented by a Cornell interaction (possibly partly vector, partly scalar). A mass formula for these mesons can then be obtained by computing analytical approximations of the eigenvalues of the equation. We show that such a formula can be derived by combining the results of two methods: the dominantly orbital state description and the Bohr-Sommerfeld quantization approach. The predictions of the mass formula are compared with accurate solutions of the spinless Salpeter equation computed with a Lagrange-mesh calculation method.Comment: 5 figure

H1N1 disseminated infection in a 3-month-old boy

Earlier this year a new influenza virus emerged. In children, the clinical manifestations of H1N1 infection are similar to those reported during periods of seasonal influenza. We report on a 3-month-old boy with an upper respiratory tract infection who presented enteropathy, coagulopathy and encephalitis related to H1N1. The infection was confirmed in nasopharyngeal aspirate, stools and cerebrospinal fluid by real-time PCR. Treatment with oseltamivir was started.info:eu-repo/semantics/publishedVersio

J/psi production at RHIC-PHENIX

The J/psi is considered to be among the most important probes for the deconfined quark gluon plasma (QGP) created by relativistic heavy ion collisions. While the J/psi is thought to dissociate in the QGP by Debye color screening, there are competing effects from cold nuclear matter (CNM), feed-downs from excited charmonia (chi_c and psi') and bottom quarks, and regeneration from uncorrelated charm quarks. Measurements that can provide information to disentangle these effects are presented in this paper.Comment: 4 pages, 3 figures, conference proceedings: the 20th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, Quark Matter 2008, Jaipur (India), 4-10 February 2008, submitted to J. Phys. G: Nuclear and Particle Physic

Punctuated equilibrium theory in Brazilian public policy: the case of Ceará

Este artigo faz uma análise do processo de decisão orçamental dos municípios do Estado do Ceará. Através deste estudo, procura-se perceber em que medida a distribuição dos orçamentos aos governos locais sofrem (ou não) variações. Já em um segundo momento, tenta-se depreender quais as receitas de cada um dos municípios (as variáveis independentes) que melhor descrevem e auxiliam a opção política de investimento local (esta será a variável dependente). Considerando o período de 2006 a 2010 e fazendo uso de um desenho de pesquisa de tipo transversal, conclui-se que nos governos locais do Ceará o investimento público apresenta períodos de estabilidade seguido por períodos de grande alteração dos orçamentos – confirmando a hipótese de pesquisa. Estas conclusões confirmam os pressupostos da teoria do equilíbrio pontuado. Conclui-se igualmente que o investimento público que vem sendo realizado é dependente das transferências que a União faz para os governos locais do Estado do Ceará e das receitas de capital. Face a estas condições, é pertinente equacionar até que nível e grau o endividamento pode ocorrer em virtude da escassez cada vez maior do financiamento público.This research aims to analyze the budget decision process in Ceará municipalities in order to understand in which way budget distributions change (or not) during the research period under consideration. This research also aims to understand which revenues (the independent variables) of each municipality better expla in the political choices for local government investments (the dependent variable). Making use of data from 2006 to 2010 and using a cross - sectional research design, the study concludes a stability in local government investments periods of stress where su ch investments have both positive and negative significant fluctuations – confirming our working hypothesis. These results confirm punctuated Equilibrium Theory assumptions and also find that local government public investment is dependent on money transfe rs from the central government and also from capital revenues. Thus, it is important to question to what degree public indebtedness should be allowed, due to a scarcity of public fundsinfo:eu-repo/semantics/publishedVersio

Faddeev approach to confined three-quark problems

We propose a method that allows for the efficient solution of the three-body Faddeev equations in the presence of infinitely rising confinement interactions. Such a method is useful in calculations of nonrelativistic and especially semirelativistic constituent quark models. The convergence of the partial wave series is accelerated and possible spurious contributions in the Faddeev components are avoided. We demonstrate how the method works with the example of the Goldstone-boson-exchange chiral quark model for baryons.Comment: 6 page

A unified meson-baryon potential

We study the spectra of mesons and baryons, composed of light quarks, in the framework of a semirelativistic potential model including instanton induced forces. We show how a simple modification of the instanton interaction in the baryon sector allows a good description of the meson and the baryon spectra using an interaction characterized by a unique set of parameters.Comment: 7 figure

Baryon spectra with instanton induced forces

Except the vibrational excitations of $K$ and $K^*$ mesons, the main features of spectra of mesons composed of quarks $u$, $d$, and $s$ can be quite well described by a semirelativistic potential model including instanton induced forces. The spectra of baryons composed of the same quarks is studied using the same model. The results and the limitations of this approach are described. Some possible improvements are suggested.Comment: 5 figure

Systematic Theoretical Search for Dibaryons in a Relativistic Model

A relativistic quark potential model is used to do a systematic search for quasi-stable dibaryon states in the $u$, $d$, and $s$ three flavor world. Flavor symmetry breaking and channel coupling effects are included and an adiabatic method and fractional parentage expansion technique are used in the calculations. The relativistic model predicts dibaryon candidates completely consistent with the nonrelativistic model.Comment: 12 pages, latex, no figure