<i>K</i>dependence in the gamma decay of neutron resonances in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">Er</mml:mi></mml:mrow><mml:mprescripts /><mml:mrow /><mml:mrow><mml:mn>168</mml:mn></mml:mrow><mml:mrow /><mml:mrow /></mml:mmultiscripts></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">Hf

Rekstad, J.; Tveter, T.S.; Guttormsen, M.; Bergholt, L.

doi:10.1103/physrevc.47.2621

Cited by 14 publications

(6 citation statements)

References 14 publications

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“…We do not know if the states with different K are already sufficiently mixed in the region of neutron resonances. The radiation capture (n, ~/) experiments [19] seem to indicate the presence of the remnants of this symmetry, but the situation is controversial. From the viewpoint of thermal fluctuations, temperature in this region is still low enough to destroy completely the geometrical symmetry since usually the energy difference between different stable mean field symmetries is at least 1-2 MeV.…”

Section: What Is Seen In Nucleimentioning

confidence: 96%

Chaos, spins and symmetries in nuclear structure

Zelevinsky

2002

Czech J Phys

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A pedagogic introduction to recent developments in "many-body quantum chaos", complicated dynamics at high level density in a finite quantum system with strong interaction between constituents, is given. Topics relating chaotic dynamics to the concept of symmetry are discussed: spectral statistics, extreme sensitivity to perturbations violating the symmetry, correlations between the states of different symmetry, and many examples of applications to nuclear structure. One of manifestations is the strikin~ predominance of ground states with zero spin in a system with arbitrary but rotationally invariant two-body interactions.1 Many-body quantum chaos 1.1 Does quantum chaos exist?The expression "quantum chaos" is controversial. The routine viewpoint [1] is that one' can speak only on "quantum signatures of classical chaos", and quantum chaos does not exist. Let us first try to understand what is the real meaning of such statements.Classical chaos is nowadays a well studied phenomenon that has found its way to the modern textbooks [2]. Moreover, the standard stuff of books in classical mechanics (two-body problem, small amplitude oscillations, rigid body rotation and so on) seems to cover only very exceptional cases of regular (integrable) motion. The majority of realistic problems, starting with the classical three-body problem, include domains of chaotic motion. There are different degrees of chaoticity [3], but for our purpose it is sufficient to characterize typ!cal features of classical chaotic dynamics in very general terms.The symmetry arguments play a key role in all considerations of chaos. Usually the idea of chaotic motion implies that all symmetries of the problem are destroyed. The simplest example can be that of a billiard, a two-dimensional area where a particle moves freely being elastically reflected from the boundaries. In a billiard of good symmetry, as round or rectangular, motion is integrable; it is characterized, apart from energy, by an additional integral of motion, angular momentum or linear momentum of the unfolded trajectory (Fig. 1), respectively. In coordinate space one trajectory can cover uniformly the entire available area; but in momentum space we keep the fixed constant of motion. In a billiard of arbitrary shape, such conservation laws are destroyed. In fact it suffices to match rectilinear and round pieces of the boundary (a stadium billiard, Fig. 2) in order to come to chaotic motion. Now a single trajectory covers an area in phase space.

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Section: What Is Seen In Nucleimentioning

confidence: 96%

Chaos, spins and symmetries in nuclear structure

Zelevinsky

2002

Czech J Phys

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“…[2]. The fact that all the M1 transitions are in the forbidden group may partially explain why the LK forbiddeness is smaller using the more reliable method.…”

Section: The Unobserved Lines Have Been Included Inmentioning

confidence: 99%

“…For the procedure to be valid, the average must include both allowed and forbidden transitions. After this approximate elimination of the spin-parity dependence in the transition probabilities, the relative intensities x, from different spin-parity groups can be compiled into one forbidden and one al- [1,2,26]). This method necessitates a more careful treatment of doublets, and in earlier works [2,26] we have developed the following stand.…”

Section: The Unobserved Lines Have Been Included Inmentioning

confidence: 99%

“…Recently, evidence has been presented [1,2] which suggests that the gamma decay of neutron resonances produced in thermal and 2 keV neutron capture shows a tendency toward K forbiddenness. This result has elicited considerable opposition [3 -5].…”

Section: Introductionmentioning

confidence: 99%

“…A second and more reliable way of analyzing this problem is described in Ref. [2]. This method takes into account that the transition intensities depend on the spin and parity of the final state, and therefore compares transitions only within the same spin and parity group.…”

Section: Introductionmentioning

confidence: 99%

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ΔKforbiddenness in neutron capture resonances inLu177

et al. 1995

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Neutron capture resonances produced in Lu by thermal neutrons are shown to gamma decay with intensities which are dependent on a AK selection rule. The difI'erence between AK-forbidden (and AK-allowed) transition rates, corrected for the energy dependence, when summed over all forbidden (and allowed) transitions and divided by the number of transitions is 1.37 photons/10 neutron captures/MeV for the forbidden transitions and 5.49 photons/10 neutron captures/MeV for the allowed transitions which gives a ratio between forbidden and allowed transitions of 0.26. If we require that allowed and forbidden transitions only be compared within the same spin and parity group, many transitions are excluded because there are no forbidden transitions to negative parity states. The average values for the forbidden and allowed transition ensembles are then 0.59 and 1.31, respectively, giving a ratio of forbidden to allowed transition intensities of 0.45. PACS number(s): 23.20.Lv, 05.45.+b, 25.40.Lw, 27.70. +q The level structure of Lu has been studied by observing neutron capture in~7 sLu [7 -13], by the beta decay of Yb [14,15], by the 160-day isomeric decay of the 23/2 state in Lu [16 -18], by the (d, p) reaction on Lu [8], and by the ( He, d) and (n, t) reactions on Yb [19]. This has led to the fairly complex one-quasiparticle B. Three-quasipartiele states in LuBecause the odd-odd nucleus &76Lu has a 3.6 x 10&o yr half-life, it serves as an excellent target for both

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72-Hafnium

Sukhoruchkin

Soroko

Tables of Excitations From Reactions With Charged Particles. Part 3: Z = 63 - 99

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Kdependence in the gamma decay of neutron resonances inEr168andHf

Cited by 14 publications

References 14 publications

Chaos, spins and symmetries in nuclear structure

Chaos, spins and symmetries in nuclear structure

ΔKforbiddenness in neutron capture resonances inLu177

72-Hafnium

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