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Experimental mirror energy differences (MED) for nuclei lying in the middle and the second part of the 1 f7/2 shell are compared with shell model calculations in the 1 f7/2 and in the full pf configuration spaces, as well as with cranked shell model calculations. MED plots are fully consistent with the description which emerges from the interpretation of SM calculations: i.e. the band-crossing of the gs band with high- K bands in A = 51 and 50 mirror pairs, as well as the seniority-3 quasi band-termination at $\ensuremath I^{\pi} = 19/2^-$ in A = 49 . Rotational alignment effects are excluded, contrarily to what even recently proposed. Some inconsistencies, as well as definition improprieties, are pointed out in the topical literature. [ABSTRACT FROM AUTHOR]

The role of the band quantum number K in influencing the character of allowed $ \beta$ transitions in heavy deformed nuclei is examined. The conditions for the occurrence of K -forbidden decays in this region are explored. Specific cases of “allowed” $ \beta$ decays proceeding via $ \Delta$ K = 2 to $ \Delta$ K = 6 channels are presented to illustrate the phenomenon. The listed $ \Delta$ K = 2 transitions, which by themselves contribute over 10% of all the presently known allowed transitions for A $ \geq$ 228 nuclei, are seen to have an average $\ensuremath\log ft \geq 9.0$ , which is clearly outside the normal range for allowed transitions. It is concluded that, wherever the $ \beta$ -connected states can be confidently labelled using the $\ensuremath I^{\pi}K$ quantum numbers, the K -forbiddenness is in general as significant as that involving the other two (spin and parity) quantum numbers. [ABSTRACT FROM AUTHOR]

By using the quark-exchange formalism, the realistic Faddeev wave function and the Fermi motion effect, we investigate the deep inelastic electron scattering from A = 3 mirror nuclei in the deep-valence region. The initial valence quark input is taken from the GRV's (Glück, Reya and Vogt) fitting procedure and the next-to-leading-order QCD evolution on F 2 p( x, Q 2) which gives a very good fit to the available data in the ( x, Q 2)-plane. It is shown that the free neutron to proton structure functions ratio can be extracted from the corresponding EMC ratios for 3He and 3H mirror nuclei by using the self-consistent iteration procedure and the results are in good agreement with the other theoretical models as well as the present available experimental data and especially the projected data expected from the proposed 11GeV Jefferson Laboratory in the near future. [ABSTRACT FROM AUTHOR]

It has been realised recently that charge symmetry of the nucleon-nucleon interaction leads to a certain relation between Asymptotic Normalization Coefficients (ANCs) in mirror-conjugated one-nucleon overlap integrals. This relation can be approximated by a simple analytical formula that involves mirror neutron and proton separation energies, the core charge and the range of the strong nucleon-core interaction. We perform detailed microscopic multi-channel cluster model calculations and compare their predictions to the simple analytical formula as well as to calculations within a single-particle model in which mirror symmetry in potential wells and spectroscopic factors are assumed. The validity of the latter assumptions is verified on the basis of microscopic cluster model calculations. For mirror pairs in which one of the states is above the proton decay threshold, a link exists between the proton partial width and the ANC of the mirror neutron. This link is given by an approximate analytical formula similar to that for a bound-bound mirror pair. We compare predictions of this formula to the results of microscopic cluster model calculations. Mirror symmetry in ANCs can be used to predict cross sections for proton capture at stellar energies using neutron ANCs measured with stable or “less radioactive” beams. [ABSTRACT FROM AUTHOR]

The properties of three pairs of mirror nuclei13N-13C,15N-15O and21Na-21Ne (these mirror nuclei are all made of a good inert core plus an unpaired valence nucleon) are investigated by using the nonlinear relativistic mean-field (RMF) theory. It is found that the calculated binding energies with two different parameter sets are very close to the experimental ones for both the ground states and the excited states except for the large deformed nuclei. The calculations show that the 2s1/2 excited states of15N and of21Na are both weakly bound with a proton halo and a proton skin (or a pigmy proton skin), respectively. In addition, the 1d5/2 excited state of13C and the 2s1/2 excited state of15O are also weakly bound with a neutron skin, respectively. The ratio of the valence nucleon radius to matter radius is deduced and it can be regarded as an additional criterion for the existence of exotic structure. The unbound 2s1/2 and 1d5/2 excited states of13N are also discussed. [ABSTRACT FROM AUTHOR]

The effects of the entrance channel and shell structure on the experimental evaporation residues have been studied by analyzing the 32S + 182W, 48Ti + 166Er and 60Ni + 154Sm reactions leading to 214Th*. the 40Ar + 181Ta reaction leading to 221Pa*; the 48 + 243Am, 248Cm, 249 reactions leading to the 291115, 296116 and 297118 superheavy compound nuclei, respectively. The fusion mechanism and the formation of evaporation residues of heavy and superheavy nuclei have been studied. In calculations of the excitation functions for capture, fusion and evaporation residues we used such characteristics as mass asymmetry of nuclei in the entrance channel, binding energies and shape of colliding nuclei, potential energy surface, driving potential, partial-fusion cross-sections and survival probability of the compound nucleus, Γn/ Γf ratio at each step along the de-excitation cascade of the compound nucleus. The calculations have allowed us to make useful conclusions about the mechanism of the fusion-fission process, which is in competition with the quasifission process, and the production of the evaporation residues. [ABSTRACT FROM AUTHOR]

The mirror nuclei 25Mg and 25A1 are expected to have very similar structures. The Gamow-Teller (GT) transitions from the J&b.pi; = 5/2+ ground state of 25Mg to the excited states in 25A1 were studied by high-resolution measurements of the 25Mg(3He, t) charge-exchange reaction at 0° and at 140 MeV/nucleon. Assuming the usual J&b.pi; = 1+ selection rule for the spin-isospin-type GT transitions, the states with J&b.pi; = 3/2+, 5/2+, and 7/2+ should be excited. However, of the more than ten states with these J&b.pi; values below 6 MeV excitation energy, only the 5/2+ ground state and the 7/2+, 1.613 MeV state in 25A1 were strongly populated, while all other states were strongly suppressed. The analysis of Mi transitions in 25Mg also suggested a very similar feature for the analogous Mi transitions. Both 25Mg and 25A1 are known to be largely deformed, and most low-lying states can be interpreted in terms of one-particle quantum numbers in the deformed potential and the associated rotational spectra. The observed suppression can be explained in terms of the K quantum number selection rules that are inherent to axially deformed nuclei. [ABSTRACT FROM AUTHOR]