Showing papers by "Chary Rangacharyulu published in 1990"

Orbital magnetic dipole strength in 148,150,152,154Sm and nuclear deformation.

Abstract: Nuclear-resonance-fluorescence spectra have been measured in the chain of $^{148,150,152,154}\mathrm{Sm}$ isotopes. Together with supplementary information from inelastic electron scattering and other reaction studies, orbital M1 transition strengths have been deduced for a number of ${1}^{+}$ states located around an excitation energy of 3 MeV. The systematic study, carried out for the first time, for nuclei within a large range of the deformation parameter \ensuremath{\delta} shows that the orbital M1 strength varies quadratically with \ensuremath{\delta}. This result is interpreted in terms of models containing explicitly neutron and proton degrees of freedom.

Total cross section for the γ d → π − pp reaction between 380 and 840 MeV

Abstract: The total cross section for the \ensuremath{\gamma}d\ensuremath{\rightarrow}${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$pp reaction has been measured for incident photon energies from 380 to 840 MeV in steps of 10 MeV, with the best energy resolution attained so far. A large-acceptance detector was used to observe the reaction products. Overall uncertainties in the deduced cross sections are less than 9% (\ensuremath{\sim}4% statistical and \ensuremath{\sim}8% systematic). The results are in excellent agreement with previous bubble chamber measurements and do not show any statistically significant structure which can be interpreted as evidence for the formation of dibaryon resonances. An upper limit at 95% confidence level of ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{peak}}$\ensuremath{\Gamma}230 \ensuremath{\mu}b MeV is obtained for a resonance in the vicinity of photon energy 700 MeV (mass\ensuremath{\sim}2490 MeV).