Pion to upsilon from kappa-deformed Poincare phenomenology

In the extreme rarity of meaningful results for four dimensional physics produced from the mathematically very well developed theory of quantum groups, we present a phenomenological fit to the rotational and radial excitations of mesons with very few parameters, From pion to upsilon, the heavy and light mesons are fitted with the same degree of precision.

CHIRAL BACKGROUND FOR THE 2-PION EXCHANGE NUCLEAR-POTENTIAL - A PARAMETRIZED VERSION

We argue that the minimal chiral background for the two-pion exchange nucleon-nucleon (NN) interaction has nowadays a rather firm conceptual basis, which entitles it to become a standard ingredient of any modern potential. In order to facilitate applications, we present a parametrized version of a configuration space potential derived previously. We than use it to assess the phenomenological contents of some existing NN potentials.

Modificacoes na ação mecânica do coração isolado de cobaia por doses de propafenon capazes de alterar o eletrocardiograma

Inotropic effects of Propafenon were studied in isovolumic isolated guinea pig hearts submitted to infusion of the drug during 10 minutes. The dosages utilized caused: bradycardia, depression of AV nodal conduction and QRS widening. Simultaneously there was: decrease of the developed pressure (DP) and of the rate of rise of pressure (dp/dt), and elongation of the time of peak pressure. Since there was no clear relation between the heart rate and the inotropic indices (PD and dp/dt), it could be supposed that the depressor effect was not due to impairment of the chronotropism only. After the infusion of Propafenon, the chronotropic effect disapeared after 15 min, while the inotropic state presented a less satisfatory recuperation. The coronary output accompanied the myocardial metabolic needs, that is to say, there was a fall during the period of depressed cardiac function and a later tendency to increase during recovery.

Pion interferometry and resonances in pp and AA collisions

We study the sensitivity of pion interferometry in pp and pp collisions at ISR energies to the resonance abundance. We show that those data are not compatible with the full resonance fractions predicted by the Lund model. The preliminary S+S and O+Au data at 200 A GeV are, however, not incompatible with the Lund predictions, although their sensitivity to resonances is significantly weaker than in the pp/pp case. © 1992.

Resolving power of 2D pion interferometry

A χ2 analysis is performed to test the resolving power of two-dimensional pion interferometry using for illustration the preliminary E802 data on Si+Au at 14.6 A GeV/c. We find that the resolving power to distinguish two decoupling geometries of different dynamical models is enhanced by studying the variation of the mean χ2 per degrees of freedom with respect to the range of the analysis in the qT, qL plane. The preliminary data seem to rule out dynamical models with significant ω, η resonance formation yields.

Patologia do Coração na AIDS. Estudo de 73 Necropsias Consecutivas

Purpose - To study the incidence and the etiology of the cardiac lesions in AIDS patients. Methods - The autopsy protocols and the filled slides of the heart from 73 consecutive AIDS patients were reviewed. There were, at least, 2 slides of each heart stained by haematoxylin-eosin; when indicated, Ziehl-Nielsen, Gram and Gomori Grocott stains were used. Results - No cause of death was assigned to the heart. There was involvement of the heart in 66 (90%) cases. Marked atrophy of cardiac fibers with or without lipomatosis was observed in 38 patients. Interstitial infiltrates of myocardium were present in 38 necropsies and in 13 of these cases a probable pathogen was demonstrated: cryptococcus neoforms in three cases and mycobacteria tuberculosis, atypical mycobacteria, toxoplasma gondii, trypanosoma cruzi and cytomegalovirus in two cases each. Bacterial endocarditis was found in 4 autopsies and Kaposi sarcome in one. The pericardium was involved in 22 cases; in 12 there was only non specific mononuclear infiltration. Conclusion - Autopsy examination of the heart from AIDS patients revealed frequent pathologic involvement.

Quark-antiquark correlation in the pion

The electromagnetic tensor for inclusive electron scattering off the pion Wμν for momentum transfers such that q+ = 0, (q+ = q0 + q3) is shown to obey a sum-rule for the component W++. From this sum-rule, one can define the quark-antiquark correlation function in the pion, which characterizes the transverse distance distribution between the quark and antiquark in the light-front pion wave-function. Within the realistic models of the relativistic pion wave function (including instanton vacuum inspired wave function) it is shown that the value of the two-quark correlation radius (rqq̄) is near twice the pion electromagnetic radius (rπ), where rπ ≈ 2/3 fm. We also define the correlation length lcorr where the two-particle correlation have an extremum. The estimation of lcorr ≈ 0.3-0,5 fm is very close to estimations from instanton models of QCD vacuum. It is also shown that the above correlation is very sensitive to the pion light-front wave-function models. © 1997 Elsevier Science B.V.

Gerasimov-Drell-Hearn sum rule and the single-pion photoproduction multipole E0+ close to threshold

The long-standing discrepancy between the Gerasimov-Drell-Hearn sum rule and the analysis of pion photoproduction multipoles is greatly diminished by use of s-wave multipoles that are in accord with the predictions of chiral perturbation theory and describe the experimental data in the threshold region. The remaining difference may be due to contributions of channels with more pions and/or heavier mesons whose contributions to the sum rule remain to be investigated by a direct measurement of the photoabsorption cross sections.

Renormalization of the one-pion-exchange interaction

A renormalization scheme for the nucleon-nucleon (NN) interaction based on a subtracted T-matrix equation is proposed and applied to the one-pion-exchange potential supplemented by contact interactions. The singlet and triplet scattering lengths are given to fix the renormalized strengths of the contact interactions. With only one scaling parameter (μ), the results show an overall very good agreement with neutron-proton data, particularly for the observables related to the triplet channel. The agreement is qualitative in the 1 S0 channel. Between the low-energy NN observables we have examined, the mixing parameter of the 3S1-3D1 states is the most sensitive to the scale. The scheme is renormalization group invariant for μ → ∞. © 1999 Elsevier Science B.V. All rights reserved.

Nucleon-nucleon interaction: Central potential and pion production

We show that the tail of the chiral two-pion exchange nucleon-nucleon potential is proportional to the pion-nucleon (πN) scalar form factor and discuss how it can be translated into effective scalar meson interactions. We then construct a kernel for the process NN → πNN, due to the exchange of two pions, which may be used in either three-body forces or pion production in NN scattering. Our final expression involves a partial cancellation among three terms, due to chiral symmetry, but the net result is still important. We also find that, at large internucleon distances, the kernel has the same spatial dependence as the central NN potential and we produce expressions relating these processes directly.