One-neutron transfer reaction and refractive effects in the 16O+16O system

Bohlen, H. G.; Khoa, Dao T.; Oertzen, W. von; Gebauer, B.; Nuoffer, F.; Bartnitzky, G.; Blažević, A.; Mittig, W.; Roussel‐Chomaz, P.

doi:10.1016/s0375-9474(01)01676-1

Cited by 7 publications

(26 citation statements)

References 21 publications

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“…Given the electric transition strengths of these states of 16 O well determined from the (e, e ′ ) data (like the Hoyle state considered here), the DWBA or CC description of high-precision inelastic 16 O+ 16 O scattering data, which cover a wide angular range and 6 orders of the cross-section magnitude, was possible only if the absorption in the exit channel is significantly increased [38]. Such an enhanced absorption was also found for the exit channel of one-neutron transfer ø17o15 reaction to the 3/2 − excited state of 15 O [39]. The enhanced absorption in the exit channel is a direct consequence of the suppression of nuclear refraction in nonelastic channels [29].…”

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confidence: 63%

“…Namely, a short-lived (excited) and loosely bound cluster like 16 O * 2 + or 15 O * 3/2 − has a shorter mean free path in the nuclear medium which implies a weaker refraction or stronger absorption [40,41] in the exit channel compared to the entrance channel where both nuclei are in their (stable) ground states (for detailed discussion see Refs. [29,38,39]). In a similar scenario, the 0 + 2 state of 12 C is very weakly bound and particle unstable (with a mean lifetime τ ≈ 10 −16 s) and it is natural to expect that the OP in the α+ 12 C * (0 + 2 ) exit channel is more absorbing than the OP in the entrance α+ 12 C channel.…”

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confidence: 99%

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Missing monopole strength of the Hoyle state in the inelastic α+12C scattering

Khoa

Cuong

2008

Physics Letters B

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Analyses of the inelastic α+ 12 C scattering at medium energies have indicated that the strength of the Hoyle state (the isoscalar 0 + 2 excitation at 7.65 MeV in 12 C) seems to exhaust only 7 to 9% of the monopole energy weighted sum rule (EWSR), compared to about 15% of the EWSR extracted from inelastic electron scattering data. The full monopole transition strength predicted by realistic microscopic αcluster models of the Hoyle state can be shown to exhaust up to 22% of the EWSR. To explore the missing monopole strength in the inelastic α+ 12 C scattering, we have performed a fully microscopic folding model analysis of the inelastic α+ 12 C scattering at E lab = 104 to 240 MeV using the 3-α resonating group wave function of the Hoyle state obtained by Kamimura, and a complex density-dependent M3Y interaction newly parametrized based on the Brueckner Hartree Fock results for nuclear matter. Our folding model analysis has shown consistently that the missing monopole strength of the Hoyle state is not associated with the uncertainties in the analysis of the α+ 12 C scattering, but is most likely due to the short lifetime and weakly bound structure of this state which significantly enhances absorption in the exit α+ 12 C * (0 + 2 ) channel.Given a vital role in the stellar synthesis of Carbon, the isoscalar 0 + 2 state at 7.65 MeV in 12 C (known as the Hoyle state) has been studied over the years in numerous experiments. Although this state was clearly identified long ago in the inelastic α+ 12 C scattering at medium energies [1,2,3,4] and inelastic electron scattering [5] as an isoscalar E0 excitation, our knowledge about its ⋆ Research supported, in part, by Natural Science Council of Vietnam, EU Asia-Link Program CN/ASIA-LINK/008 (94791) and Vietnam Atomic Energy Commission (VAEC).

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confidence: 63%

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confidence: 99%

Missing monopole strength of the Hoyle state in the inelastic α+12C scattering

Khoa

Cuong

2008

Physics Letters B

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“…In general, due to a stronger absorption, these non-elastic rainbow Figure 34. Results of the DWBA calculation for the ø17o15 one-neutron transfer reaction to the 15 O 1/2 − ground state at E lab = 250 → 1120 MeV in comparison with the data [108]. The dashed curves were obtained with the same complex OP for the 17 [108] patterns (which have no counterparts in the optical rainbow) should be less pronounced and harder to observe experimentally.…”

Section: Rainbow Features In Other Quasi-elastic Scattering Channelsmentioning

confidence: 92%

“…Results of the DWBA calculation for the ø17o15 one-neutron transfer reaction to the 15 O 1/2 − ground state at E lab = 250 → 1120 MeV in comparison with the data [108]. The dashed curves were obtained with the same complex OP for the 17 [108] patterns (which have no counterparts in the optical rainbow) should be less pronounced and harder to observe experimentally. The rainbow effects have been investigated, e.g., in the inelastic scattering and one-neutron transfer reactions measured with 12,13 C+ 12 C systems at the energy of 20 MeV/nucleon [13].…”

Section: Rainbow Features In Other Quasi-elastic Scattering Channelsmentioning

confidence: 92%

Nuclear rainbow scattering and nucleus–nucleus potential

Khoa

Oertzen

Bohlen

et al. 2007

J. Phys. G: Nucl. Part. Phys.

197

308

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Abstract. Elastic scattering of α-particle and some tightly-bound light nuclei has shown the pattern of rainbow scattering at medium energies, which is due to the refraction of the incident wave by a strongly attractive nucleus-nucleus potential. This review gives an introduction to the physics of the nuclear rainbow based essentially on the optical model description of the elastic scattering. Since the realistic nucleusnucleus optical potential (OP) is the key to explore this interesting process, an overview of the main methods used to determine the nucleus-nucleus OP is presented. Given the fact that the absorption in a rainbow system is much weaker than that usually observed in elastic heavy-ion scattering, the observed rainbow patterns were shown to be linked directly to the density overlap of the two nuclei penetrating each other in the elastic channel, with a total density reaching up to twice the nuclear matter saturation density ρ 0 . For the calculation of the nucleus-nucleus OP in the doublefolding model, a realistic density dependence has been introduced into the effective M3Y interaction which is based originally on the G-matrix elements of the Reid-and Paris nucleon-nucleon (NN) potentials. Most of the elastic rainbow scattering data were found to be best described by a deep real OP like the folded potential given by this density dependent M3Y interaction. Within the Hartree-Fock formalism, the same NN interaction gives consistently a soft equation of state of cold nuclear matter which has an incompressibility constant K ≈ 230 − 260 MeV. Our folding analysis of numerous rainbow systems has shown that the elastic α-nucleus and nucleus-nucleus refractive rainbow scattering is indeed a very helpful experiment for the determination of the realistic K value. The refractive rainbow-like structures observed in other quasielastic scattering reactions have also been discussed. Some evidences for the refractive effect in the elastic scattering of unstable nuclei are presented and perspectives for the future studies are discussed.

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“…The appearance of such effects depends on the correspondence between a number of parameters of the entrance and exit channels (see, e.g., Refs. [5,6]). The procedure for identifying Airy minima in transfer reaction angular distributions is similar to that used in the case of elastic scattering (e.g., Refs.…”

Section: Introductionmentioning

confidence: 99%

S-matrix Description of Refractive Effects in One-nucleon Stripping Reactions Induced by \(\alpha \)-particles on \(^{28}\)Si

Berezhnoy¹,

Molev²

2022

Acta Phys. Pol. B

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We analyze the angular distributions for the (α, 3 He) and (α, t) reactions on 28 Si for projectile energies ranging from 50 to 120 MeV based on the partial-wave representation of the transfer amplitude expressed in terms of the S-matrices for the entrance and exit channels, with an emphasis on identifying Airy minima of various orders. The calculations have been performed using a six-parameter S-matrix model and S-matrix parameters obtained from the analysis of elastic scattering data. The first-and (or) second-order Airy minima are clearly identified in the analyzed transfer reaction angular distributions at intermediate angles. The detected Airy minima are found to be due to the interference between several inner and surface partial waves. The impact parameters of these waves are in the range of 1-6 fm, the upper boundary of which is less than the strong absorption radius.

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One-neutron transfer reaction and refractive effects in the 16O+16O system

Cited by 7 publications

References 21 publications

Missing monopole strength of the Hoyle state in the inelastic α+12C scattering

Missing monopole strength of the Hoyle state in the inelastic α+12C scattering

Nuclear rainbow scattering and nucleus–nucleus potential

S-matrix Description of Refractive Effects in One-nucleon Stripping Reactions Induced by \(\alpha \)-particles on \(^{28}\)Si

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