RESUMO
Exclusive measurements of the quasifree ppâppπ^{+}π^{-} reaction have been carried out at WASA@COSY by means of pd collisions at T_{p}=1.2 GeV. Total and differential cross sections have been extracted covering the energy region T_{p}=1.08-1.36 GeV, which is the region of N^{*}(1440) and Δ(1232)Δ(1232) resonance excitations. Calculations describing these excitations by t-channel meson exchange are at variance with the measured differential cross sections and underpredict substantially the experimental total cross section. An isotensor ΔN dibaryon resonance with I(J^{P})=2(1^{+}) produced associatedly with a pion is able to overcome these deficiencies.
RESUMO
Taking advantage of the high acceptance and axial symmetry of the WASA-at-COSY detector, and the high polarization degree of the proton beam of COSY, the reaction p[over â]pâppη has been measured close to threshold to explore the analyzing power A_{y}. The angular distribution of A_{y} is determined with the precision improved by more than 1 order of magnitude with respect to previous results, allowing a first accurate comparison with theoretical predictions. The determined analyzing power is consistent with zero for an excess energy of Q=15 MeV, signaling s-wave production with no evidence for higher partial waves. At Q=72 MeV the data reveal strong interference of Ps and Pp partial waves and cancellation of (Pp)^{2} and Ss^{*}Sd contributions. These results rule out the presently available theoretical predictions for the production mechanism of the η meson.
RESUMO
Two children showed evidence of alpha-pattern coma (APC). One case followed a phenobarbital sodium overdose with complete recovery. The second case occurred subsequent to cardiopulmonary arrest with unfavorable outcome. These cases and others that we reviewed emphasize that the prognosis of APC in children, as in adults, is variable and appears to be related to the cause.