Isobaric spin

The partial sucess/failure slowed down the applications, especially as the computers at that time were too slow to manage larger model spaces and additional, more complicated, A -representability conditions. Some hope was offered by applying symmetries—orbital rotation, spin, isobaric spin—and it was stimulating to explore them with Bob Erdahl and my younger collaborator Bojan Golli [32], However, new ideas were needed. 

The term isobaric spin is also frequently used. 

We note that also other types of isovector giant resonances have been suggested as a source of information on the neutron skin, such as the spin-dipole giant resonance [33] and the isobaric analog state [34], At present studies of these reactions have not led to quantitative constraints for the neutron skin of... 

Newton (/ ) and of Cameron (17) have been tried and the values of Zp calculated do not show sharp discontinuities at shell crossings. The mass formula of Cameron takes shell effects and spin terms into account much as does the mass formula of Kumar and Preston, however, the mass formula of the latter is specifically used for isobaric sequences which show discontinuities in 8-decay energies versus charge curves when shells are crossed. 

MeV level is likely to have isotopic spin zero since it breaks up into the systems (Li + a) and (Be + /) and the 0.72 and 2.15 MeV levels are similarly T = 0 because the T = i level is definitely identified at I.74 MeV by comparison with isobaric nuclei and by inelastic scattering experiments. The spin of the 0.72 MeV level is set at 1" or 2" by the angular correlation experiment, which is consistent with the Mi —E2 correlation although the latter may be a mixture oi E 2 and M1. The apparent failure of the isotopic spin dipole selection rule may be due to the interference of a 1" state with T = 1 near the 6.89 MeV level of B . 

The beta transition between the isobars has the superallowed character. The lower levels of the two nuclei show similar structure and spins, although the first... 

The beta transitions are both simple that of is of very low energy, so that the excitation of the first T = state in CP is at an energy approximately equal to the isobaric correction. The spin of the radioactive nucleus has been measured and is found to be f, in agreement with the // prediction for d l. The magnetic moment of CP agrees better with the prediction from this same configuration than with the Schmidt value for d /. The S ->CP decay is allowed, but not superallowed since these nuclei are not a true mirror pair. 

The nucleus K is unstable with respect to decay into both its even-even isobars. Because of its high spin the corresponding beta transitions are highly forbidden, and the lifetime is 14.6 X 10 yr. The transition is to the ground state of Ca and the electron capture transition to the first excited state (probably... 

The similarity of the proton and neutron was one of the earliest observations indicating a possible compositeness of the elementary particles they have almost identical masses and -in spite of the fact that the proton has electric charge and the neutron has none - they have very similar potentials in the nuclear field. The concept of the nucleon was introduced with two eigenstates, neutron and proton, and a quantum number, the isospin. Its only similarity to spin is that it belongs to the same symmetry group, SU(2). Iso stands for isobaric. isobars are a set of nuclei of the same mass number but different charge and they can be identified using the isospin quantum number. 

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