Experimental test of the brink hypothesis

Szefliński, Z.; Szeflińska, G.; Wilhelmi, Z.; Rza̧ca‐Urban, T.; Klapdor, H. V.; Anderson, E. W.; Grotz, K.; Metzinger, J.

doi:10.1016/0370-2693(83)90582-8

Cited by 16 publications

(14 citation statements)

References 12 publications

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“…Within the GDR range it agrees quantitatively to the (γ,n)-data, which -of course -are connected to the ground state. As stated [45], this fact constitutes an impressive test of the Axel-Brink hypothesis [28,46]. Additionally, these data show a perfect agreement to a single Lorentzian with = 4 MeV, = 1 and = 0.…”

Section: Comparison To Previous Strength Function Studiessupporting

confidence: 56%

Nuclear dipole strength in the tail of the giant dipole resonance (GDR)

Grosse¹

2008

Proceedings of Workshop on Photon Strength Functions and Related Topics — PoS(PSF07)

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A hitherto unexplored method for the experimental determination of the photon strength function up to the neutron separation energy was developed at the Radiation Source ELBE in Dresden. It was applied to various heavy nuclei, preferentially to nuclides with increasing distance to the N=50 neutron shell, and it covers the high level density excitation energy range above 4 MeV. The observed quasi-continuous spectra of scattered photons can be -after a proper correction for multi-step processes -directly combined to nuclear photo effect data from literature. A remarkably good match of the photon strengths as measured below and above the neutron emission threshold is observed. The wide energy coverage of the combined data forms an excellent basis to derive a parameterization for the dipole strength function fully covering the range across the nucleon separation energies. In addition to the parameters defining the deformation of the nuclear ground states only one additional constant is needed to describe the dipole strength in the nuclei with 88

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Section: Comparison To Previous Strength Function Studiessupporting

confidence: 56%

Nuclear dipole strength in the tail of the giant dipole resonance (GDR)

Grosse¹

2008

Proceedings of Workshop on Photon Strength Functions and Related Topics — PoS(PSF07)

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“…The BH has been shown to be a reasonable concept for the GDR at low excitation energies in a variety of experiments, including those measuring average intensities of primary transitions from (n,γ) [11], (p,γ) [12], and (γ, γ ′ ) reactions [13]. Reactions with light ions which double excite the GDR also substantiate the BH [14,15].…”

mentioning

confidence: 99%

Evidence for radiative coupling of the pygmy dipole resonance to excited states

et al. 2012

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“…Note that that work defines q in the negative sense of its use here; that is to say, q in that work is defined as the parent energy minus the daughter energy. Up until neutrino trapping sets in at ρ ∼ 10 12 g/cm 3 , we may take f ν ≈ 0. Here f e (w,μ e ,T ) is the Fermi-Dirac distribution (1 + e (wm e −μ e )/T ) −1 .…”

Section: Computation Of Capture Ratementioning

confidence: 99%

“…During supernova core collapse, the density is very high, starting at around 10 10 g/cm 3 at the onset of collapse and proceeding to >10 14 g/cm 3 at bounce. The temperature is very high at ∼1-2 MeV, but the entropy per baryon is extremely low at ≈1 unit of Boltzmann's constant per baryon [33].…”

Section: Introductionmentioning

confidence: 99%

“…That is, if a given nucleus in its ground state has the resonance at 10 MeV excitation, then that same nucleus in an excited state would have that resonance at 10 MeV above the excited level, and indeed experiment bears this out [3]. The idea that the response properties of excited states might be similar to those of the ground state is alluring, especially for astrophysical weak interaction calculations, in part because it can be difficult to measure or calculate excited-state properties and relatively easier to study ground-state properties.…”

Section: Introductionmentioning

confidence: 99%

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Modification of the Brink-Axel hypothesis for high-temperature nuclear weak interactions

2014

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We present shell-model calculations of electron capture strength distributions in A = 28 nuclei and computations of the corresponding capture rates in supernova core conditions. We find that in these nuclei the Brink-Axel hypothesis for the distribution of Gamow-Teller strength fails at low and moderate initial excitation energy but may be a valid tool at high excitation. The redistribution of GT strength at high initial excitation may affect capture rates during collapse. If these trends which we have found in lighter nuclei also apply for the heavier nuclei which provide the principal channels for neutronization during stellar collapse, then there could be two implications for supernova core electron capture physics. First, a modified Brink-Axel hypothesis could be a valid approximation for use in collapse codes. Second, the electron capture strength may be moved down significantly in transition energy, which would likely have the effect of increasing the overall electron capture rate during stellar collapse.

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Experimental test of the brink hypothesis

Cited by 16 publications

References 12 publications

Nuclear dipole strength in the tail of the giant dipole resonance (GDR)

Nuclear dipole strength in the tail of the giant dipole resonance (GDR)

Evidence for radiative coupling of the pygmy dipole resonance to excited states

Modification of the Brink-Axel hypothesis for high-temperature nuclear weak interactions

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