On a recent paper of Misra et al

Ward, J. P.

doi:10.1088/0305-4470/7/13/001

Cited by 24 publications

(33 citation statements)

References 6 publications

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“…If we assume the 22 Mg+p structure, J π = 5/2 + allows three different configurations: (i) the ground state of 22 Mg (J π = 0 + ) couples to the d-wave valence proton, (ii) the first excited state of 22 Mg (E x =1.25 MeV, J π = 2 + ) couples to the s-wave valence proton, and (iii) the first excited state of 22 (ii) is only 0.2%, and that of case (iii) is 23%. It is noted that, in the mirror partner 23 Ne, the d-wave valence neutron is dominant in the ground state, which was shown by the 22 Ne(d, p) 23 Ne reactions [26]. Thus, the configuration with the d-wave valence proton is the most probable for 23 Al.…”

Section: Rapid Communicationsmentioning

confidence: 96%

Measurement of the spin and magnetic moment ofAl23

et al. 2006

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For the first time, we obtained the g factor for the ground state of 23 Al by use of a β-NMR measurement. 23 Al has a small proton separation energy and is a potential proton-halo candidate. The obtained g factor, |g| = 1.557 ± 0.088, clearly shows the spin and parity, J π = 5/2 + , for 23 Al, which is the same as that of its mirror partner, 23 Ne. The possible nuclear structure of 23 Al is also discussed. Studies of exotic nuclei far from the stability line have attracted much interest during the past two decades since the first observation of the neutron halo in 11 Li [1]. Further experiments have confirmed the neutron halo in 11 Li, and have also shown the existence of a neutron halo in other neutron-rich nuclei [2]. However, the number of experiments on the proton halo are relatively few compared with those on the neutron halo. Recently, experimental evidence for the proton halo in very proton-rich nuclei has become available: 8 B [3][4][5], 17 Ne [6,7], and 26,27,28 P [8]. 23 Al is one of the potential candidates for a proton-halo nucleus, because its proton separation energy is quite small (125 keV). Recently, a large reaction cross section of 23 Al was measured at the intermediate energy (∼36A MeV), although the error was still large [9,10]. The authors of Ref. [9,10] analyzed the data by a Glauber model with simply a core nucleus ( 22 Mg) plus a valence proton (p) configuration. According to their analysis, the density distribution of 23 Al should have a halolike long tail. Because the density of a loosely bound s-wave proton can be extended, it is suggested that the spin and parity (J π ) of 23 Al might be 1/2 + . However, the J π of its mirror partner, 23 Ne, is 5/2 + . Thus, if the ground-state J π of 23 Al is 1/2 + , the proton halo structure can be anticipated, but the mirror symmetry will be broken between the bound ground states of mirror pairs, which has not been observed for known nuclei so far. Because the magnetic moment of its mirror partner, 23 Ne, is known to be −1.077±0. 004 [11], the magnetic moment of 23 Al allows one to discuss the spin expectation value [12] of the A = 23 mirror pair with T = 3/2, where T is the isobaric spin. In p-shell nuclei, the 9 C-9 Li mirror moments (T = 3/2) yield an anomalous large spin expectation value, which suggests an exotic structure of proton-rich 9 C [13]. A similar anomaly may be found in the sd-shell region.Determining

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Section: Rapid Communicationsmentioning

confidence: 96%

Measurement of the spin and magnetic moment ofAl23

et al. 2006

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“…In these nuclei, in fact, the yrast negative-parity even-spin band can be observed down to as low a spin and an excitation energy as 4h and ∼2 MeV and provides, basically, the whole feeding of the lowest-observed negative-parity odd-spin states, through M1(+E2) transitions [4][5][6]. The lowest-observed negative-parity levels, however, lie below the energy threshold represented by twice the proton pairing gap 1 in all even barium isotopes with 118 A 126 [4][5][6][7][8][9]. This, excluding a simple quasiproton interpretation, hints at a possible role of octupole correlations in the origin of low-lying negative-parity levels.…”

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confidence: 99%

Evidence for octupole correlations inBa124,125

Mason¹,

Benzoni²,

Bracco³

et al. 2005

Phys. Rev. C

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The γ decay of the nuclei 124,125 Ba has been investigated by means of the EUROBALL spectrometer, coupled to the DIAMANT array of charged-particle detectors, using the reaction 64 Ni + 64 Ni at E beam = 255 and 261 MeV. In the nucleus 125 Ba six new E1 transitions have been found to link opposite-parity bands currently interpreted as νd 5/2 (+g 7/2 ), νh 11/2 structures. The previously unknown J π = 3 − level in the nucleus 124 Ba has also been identified; its excitation energy is accurately reproduced by a microscopic calculation including octupole correlations. Both issues are bolstered by sizable B(E1)/B(E2) ratios.

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“…Deorientation effect measurements corresponding to this "hot ionization" situation have been carried out in light (A ss40) and heavy (A χ 150) nuclei [101][102][103][104][105][106][107], The results have been summarized by Goldring [108] and Sprouse [109]. If one treats the electronic rearrangement as a statistical process, the fluctuating magnetic fields introduce a time dependence of the γ-ray angular distribution with Legendre polynomial coefficients A k (t) = A k G k (t)(k = 2,4).…”

Section: B) Delayed Feedingsmentioning

confidence: 99%

12 The Measurement of Nuclear Lifetimes

1997

Experimental Techniques in Nuclear Physics

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Table of Contents I. Scope and definitions 425 II. Decay constants of "rare" decays 427 A. Very long lifetimes 427 B. Very small activities 428 C. Precision studies of the neutron lifetime 434 III. Direct timing methods (10~6 > τ > 10" 15 s) 437 A. Electronic and pulsed beam timing methods 437 B. Recoil shadow timing methods 445 C. The recoil distance "plunger" method 447 D. The Doppler shift attenuation method 453 E. The GRID method 466 IV. Measurement of very short lifetimes (τ < 10" 15 s) 472 A. X-ray timing 473 B. Crystal blocking 474 C. Nuclear resonance fluorescence 475 D. Determination of narrow resonance widths 478 References 482 I. Scope and definitionsThe decay modes of ground states and the low-lying nuclear states up to about 10 MeV excitation energy via ß-decay, electromagnetic radiations, particle emission and/or fission have been extensively studied for many decades. In all domains of nuclear structure investigations, the measurement of absolute decay probabilities and nuclear lifetimes has given important insight into the facets of nuclear many-body systems and has provided detailed data for in-depth tests of nuclear models. Some of these decay modes involve fundamentally known interactions, e.g. the electro-weak interaction in the case of β-and γ-decay processes, and thus are directly sensitive to the nuclear model wave functions to be tested. Other processes like nucleon emission, α-decay and fission are more difficult to deal with theoretically, as here the wave functions of the nuclear states involved in the transition and the nuclear transition operator, which both determine the decay probabilities, depend on the model used.The experimentally accessible range of nuclear lifetimes covers more than forty-five (!) orders of magnitude. When just considering α-decays, we have, on the one hand, the Unauthenticated Download Date | 6/13/16 9:10 AM

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On a recent paper of Misra et al

Cited by 24 publications

References 6 publications

Measurement of the spin and magnetic moment ofAl23

Measurement of the spin and magnetic moment ofAl23

Evidence for octupole correlations inBa124,125

12 The Measurement of Nuclear Lifetimes

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