Proton resonant states in 18Ne have been investigated by the resonant scattering of 17F+p with a 17F beambombarding a thick H2 gas target. Several resonances have been observed. In particular, the astrophysically cruc...Proton resonant states in 18Ne have been investigated by the resonant scattering of 17F+p with a 17F beambombarding a thick H2 gas target. Several resonances have been observed. In particular, the astrophysically crucialstate 6.15 MeV was observed as a spin-parity assignment of 1?? with high statistics. The groove-like structureobserved in this work is completely different with previous peak one[1]. The confirmation of 1?? on a firm groundclarified this significant discrepancy. In addition, a new state was observed at Ex = 6.85 MeV with a tentativespin assignment of 0, which could be the mirror state of 6.88 MeV, 0?? in 18O, or a bandhead state (0+) of thesix-particle four-hole (6p-4h) band[2,3]. The resonant parameters have been determined by an R-matrix analysis ofthe excitation functions.展开更多
The lifetime of the first excited 2+ state in 18C was measured using an upgraded recoil shadow method to determine the electric quadrupole transition. The measured mean lifetime is 18.9±0.9(stat)±4.4(syst)ps...The lifetime of the first excited 2+ state in 18C was measured using an upgraded recoil shadow method to determine the electric quadrupole transition. The measured mean lifetime is 18.9±0.9(stat)±4.4(syst)ps,which corresponds to a B(E2; 2+1→0+gs) value of (4.3± 0.2±1.0) e2fm4,or about 1.5 Weisskopf units. The mean lifetime of the first 2+ state in 16C was remeasured to be about 18 ps,about four times shorter than the value reported previously. This discrepancy was explained by incorporating the γ-ray angular distribution measured in this work into the previous measurement. The observed transition strengths in 16,18C are hindered compared to the empirical transition strengths,indicating that the anomalous hindrance observed in 16C persists in 18C.展开更多
文摘Proton resonant states in 18Ne have been investigated by the resonant scattering of 17F+p with a 17F beambombarding a thick H2 gas target. Several resonances have been observed. In particular, the astrophysically crucialstate 6.15 MeV was observed as a spin-parity assignment of 1?? with high statistics. The groove-like structureobserved in this work is completely different with previous peak one[1]. The confirmation of 1?? on a firm groundclarified this significant discrepancy. In addition, a new state was observed at Ex = 6.85 MeV with a tentativespin assignment of 0, which could be the mirror state of 6.88 MeV, 0?? in 18O, or a bandhead state (0+) of thesix-particle four-hole (6p-4h) band[2,3]. The resonant parameters have been determined by an R-matrix analysis ofthe excitation functions.
基金Ministry of Education, Culture,Sports,Science and Technology of Japan(15204017,20740163)
文摘The lifetime of the first excited 2+ state in 18C was measured using an upgraded recoil shadow method to determine the electric quadrupole transition. The measured mean lifetime is 18.9±0.9(stat)±4.4(syst)ps,which corresponds to a B(E2; 2+1→0+gs) value of (4.3± 0.2±1.0) e2fm4,or about 1.5 Weisskopf units. The mean lifetime of the first 2+ state in 16C was remeasured to be about 18 ps,about four times shorter than the value reported previously. This discrepancy was explained by incorporating the γ-ray angular distribution measured in this work into the previous measurement. The observed transition strengths in 16,18C are hindered compared to the empirical transition strengths,indicating that the anomalous hindrance observed in 16C persists in 18C.
