RESUMO
We observed the atomic 1s and 2p states of π^{-} bound to ^{121}Sn nuclei as distinct peak structures in the missing mass spectra of the ^{122}Sn(d,^{3}He) nuclear reaction. A very intense deuteron beam and a spectrometer with a large angular acceptance let us achieve a potential of discovery, which includes the capability of determining the angle-dependent cross sections with high statistics. The 2p state in a Sn nucleus was observed for the first time. The binding energies and widths of the pionic states are determined and found to be consistent with previous experimental results of other Sn isotopes. The spectrum is measured at finite reaction angles for the first time. The formation cross sections at the reaction angles between 0° and 2° are determined. The observed reaction-angle dependence of each state is reproduced by theoretical calculations. However, the quantitative comparison with our high-precision data reveals a significant discrepancy between the measured and calculated formation cross sections of the pionic 1s state.
Assuntos
Pteridinas , Urina , Fenômenos Químicos , Química , Cromatografia em Papel , Cristalização , Eletroforese , Humanos , Ácido Clorídrico , Raios Infravermelhos , Manganês , Oxirredução , Hidróxido de Sódio , Análise Espectral , Raios Ultravioleta , ÁguaRESUMO
A WWW-based, on-line, data-entry system for the collection of statistical data on the management of Japanese national university hospitals has been developed. Trial operation of the system showed that it can reduce the labour and budgetary costs of data collection and also demonstrated that an on-line, data-entry system is feasible in Japan. In April 1997, we began production use of the system, and we are to develop another WWW-based data-entry system that can deal with all other statistics on hospital management.