The transition rates for the 2(1)+ states in (62,64,66)Fe were studied using the recoil distance Doppler-shift technique applied to projectile Coulomb excitation reactions. The deduced E2 strengths ...illustrate the enhanced collectivity of the neutron-rich Fe isotopes up to N = 40. The results are interpreted using the generalized concept of valence proton symmetry which describes the evolution of nuclear structure around N = 40 as governed by the number of valence protons with respect to Z ≈ 30. The trend of collectivity suggested by the experimental data is described by state-of-the-art shell-model calculations with a new effective interaction developed for the fpgd valence space.
Coulomb excitation of 74,76Zn Illana, A.; Zielińska, M.; Huyse, M. ...
Physical review. C,
10/2023, Letnik:
108, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The first experiment using radioactive beams post-accelerated by the HIE-ISOLDE facility has enabled to obtain a precise set of B(E2) transition probabilities in neutron-rich 74,76Zn isotopes. The ...resulting B(E2; 2+1→0+1) values are consistent with those determined in earlier REX-ISOLDE measurements. While the B(E2; 4+1→2+1) transition probability in 76Zn is also in agreement with earlier Coulomb-excitation results, the value obtained for 74Zn is considerably lower. For the first time, a spectroscopic quadrupole moment of the 2+1 state was measured for an exotic nucleus in this mass region. A detailed comparison is presented with large-scale shell-model and Monte Carlo shell-model calculations.
Coulomb excitation of Zn74,76 Illana, A.; Zielińska, M.; Huyse, M. ...
Physical review. C,
10/2023, Letnik:
108, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The first experiment using radioactive beams post-accelerated by the HIE-ISOLDE facility has enabled to obtain a precise set of B(E2)transition probabilities in neutron-rich Zn74,76 isotopes. The ...resulting B(E2; 2+1→0+1) values are consistent with those determined in earlier REX-ISOLDE measurements. While the B(E2; 4+1→2+1) transition probability in Zn76 is also in agreement with earlier Coulomb-excitation results, the value obtained for Zn74 is considerably lower. For the first time, a spectroscopic quadrupole moment of the 2+1 state was measured for an exotic nucleus in this mass region. A detailed comparison is presented with large-scale shell-model and Monte Carlo shell-model calculations.
Excited states have been studied in 35Ar following the 16O(24Mg,1alpha1n)35Ar fusion-evaporation reaction at 60 MeV using the Ge-detector array GASP. A comparison with the mirror nucleus 35Cl shows ...two remarkable features: (i) A surprisingly large energy difference for the 13/2(-) states, in which the hitherto overlooked electromagnetic spin-orbit term is shown to play a major role, and (ii) a very different decay pattern for the 7/2(-) states, which provides direct evidence of isospin mixing.
The lifetimes of the first excited states of the N=30 isotones Ca-50 and Sc-51 have been determined using the Recoil Distance Doppler Shift method in combination with the CLARA-PRISMA spectrometers. ...This is the first time such a method is applied to measure lifetimes of neutron-rich nuclei populated via a multinucleon transfer reaction. This extends the lifetime knowledge beyond the f(7/2) shell closure and allows us to derive the effective proton and neutron charges in the fp shell near the doubly magic nucleus Ca-48, using large-scale, shell-model calculations. These results indicate an orbital dependence of the core polarization along the fp shell.
To test the hypothesis that 5,10-methylenetetrahydrofolate reductase (MTHFR) polymorphisms modify the risk of pancreatic cancer,
we conducted a hospital-based, case-control study involving 347 ...patients with newly diagnosed pancreatic adenocarcinoma and
348 healthy controls, frequency matched by age, sex, and race. MTHFR polymorphisms were determined using the PCR-RFLP method. Association of these polymorphisms with the risk of pancreatic cancer
was estimated by unconditional logistic regression analysis. We found that the C667T (but not the A1298C) polymorphism had
a significant main effect on the risk of pancreatic cancer. The frequencies of the MTHFR 667CC, 667CT, and 667TT genotypes were 49.5%, 38.6%, and 11.9%, respectively, among cases compared with 48.5%, 45.0%, and
6.5%, respectively, among controls. Individuals with the 667TT genotype displayed a 2-fold increased risk for pancreatic cancer
compared with those with the CC/CT genotypes adjusted odds ratio (OR), 2.14; 95% confidence interval (95% CI), 1.14-4.01.
Multivariate analyses found that the effect of the 677TT genotype on the risk of pancreatic cancer was present among ever
smokers (OR, 5.53; 95% CI, 2.0-15.3) and ever alcohol drinkers (OR, 3.16; 95% CI, 1.30-7.69) but not in never smokers (OR,
0.82; 95% CI, 0.33-2.06) and never drinkers (OR, 1.42; 95% CI, 0.56-3.62). Furthermore, a positive interaction between the
MTHFR TT genotype and heavy smoking or heavy alcohol consumption was detected. The OR (95% CI) of pancreatic cancer was 6.83 (1.91-24.38)
for heavy smokers among the TT carriers compared with never smokers with the CC/CT genotypes and 4.23 (0.88-20.3) for heavy
drinkers with the TT genotype compared with nondrinkers with the CC/CT genotypes. These observations support a role for folate
metabolism in pancreatic cancer, especially among smokers and heavy drinkers.
Excited states in 63,65,67Mn were studied via in-beam γ -ray spectroscopy following knockout reactions from 68Fe. Similar level schemes, consisting of the 11/2−, 9/2−, 7/2− and 5/2− g.s. level ...sequence, connected by I → I − 1 transitions, were established, the first time for 65,67Mn. Their level structures show features consistent with strongly-coupled rotational bands with K = 5/2. State-of-the-art shellmodel calculations with the modified LNPS effective interaction reproduce the observed levels remarkably well and suggest the dominance of 4-particle-4-hole neutron configurations for all the states. The data on the low-lying excited states of odd-mass 53−67Mn provide a textbook example of nuclear structure evolution from weak coupling through decoupling to strong coupling along a single isotopic chain on the n-rich side of the β stability line. These results help to deepen our understanding of the N = 40 “island of inversion”.
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