Study of reactions induced by 6He on 9Be

We present the results of experiments using a 6He beam on a 9Be target at\ud energies 7 − 9 times the Coulomb barrier. Angular distributions of the elastic, inelastic\ud scattering (target breakup) and the -particle production in the 6He+9Be collision have\ud been analysed. Total reaction cross sections were obtained from the elastic scattering\ud analyses and a considerable enhancement has been observed by comparing to stable systems.FAPESPFundação Araucári

The Li-8(p, alpha)He-5 reaction at low energies, and Be-9 spectroscopy around the proton threshold

We present a direct measurement of the low-energy Li-8(p, alpha)He-5 cross section, using a radioactive Li-8 beam impinging on a thick target. With four beam energies, we cover the energy range between E-c.m. = 0.2 and 2.1 MeV. An R-matrix analysis of the data is performed and suggests the existence of two broad overlapping resonances (5/2(+) at E-c.m. = 1.69 MeV and 7/2(+) at E-c.m. = 1.76 MeV). At low energies our data are sensitive to the properties of a subthreshold state (E-x = 16.67 MeV) and of two resonances above threshold. These resonances were observed in previous experiments. The R-matrix fit confirms spin assignments, and provides partial widths. We propose a new Li-8(p, alpha)He-5 reaction rate and briefly discuss its influence in nuclear astrophysics. DOI: 10.1103/PhysRevC.86.064321Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [2003/10099-2, 2004/07379-6, 2008/09341-7]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Comissao de Aperfeicoamento do Ensino Superior (CAPES)Comissao de Aperfeicoamento do Ensino Superior (CAPES

Efeito da transferência-alfa no sistema 'ANTPOT.16 O' + 'ANTPOT.24 MG'

Efeito da transferência-alfa no sistema \'ANTPOT.16 O\' + \'ANTPOT.24 MG\'Efeito da transferência-alfa no sistema \'ANTPOT.16 O\' + \'ANTPOT.24 MG\

Estudo do sistema ANTPOT.12 C + ANTPOT.24 MG

ESTUDO DO SISTEMA 12C + 24MgEstudo do sistema ANTPOT.12 C + ANTPOT.24 M

alpha-Spectroscopic factor of (16)O(gs) from the (12)C((16)O,(12)C)(16)O reaction

Elastic scattering angular distributions of (16)O + (12)C in the center of mass energy range from 8.55 MeV to 56.57 MeV have been analyzed considering the effect of the exchange of an alpha particle between projectile and target leading to the same nuclei of the entrance channel (elastic-transfer). An alpha particle spectroscopic factor for the ground state of the (16)O was determined. (C) 2011 Elsevier B.V. All rights reserved.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2008/09341-7]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CAPES (Comissao de Aperfeicoamento do Ensino Superior)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Decoherence of quantum kinematical correlations: Elastic scattering of identical particles

We include the dynamics of the angular straggling process in the angular distributions of Mott scattering of heavy ions. We model the passage of an incoming nucleus through a target as a diffusion process. It is then possible to derive a simple and physically transparent expression for the angular dispersion due to the straggling. The angular dispersion should be folded with the theoretical Mott cross section to see its effect on the amplitude of the Mott oscillations. Our results agree very well with data of Pb-208 + Pb-208 scattering. We define the "classical" limit as the limit when the angular dispersion due to straggling becomes comparable with the Mott oscillation period and get the disappearance of quantum interference occurring at the limit 0.050 root xi Z(4)/E-3/2 >= 1, where xi stands for the target thickness, Z is the system's charge, and E is the center-of-mass energy. The experiments on lead are very close to this limit. We show that the kinematical correlations due to the identity of the particles is maintained, as it should be, and the action of the environment is to reduce the fringe visibility

Elongated shape isomers in the (36)Ar nucleus

A recent analysis of the (12)C + (24)Mg scattering [W. Sciani et al., Phys. Rev. C 80, 034319 (2009)] suggests the existence of a hyperdeformed band in the (36)Ar nucleus, completely in line with the predictions of alpha [W. D. M. Rae and A. C. Merchant, Phys. Lett. B279, 207 (1992)] and binary cluster calculations [J. Cseh et al., Phys. Rev. C 70, 034311 (2004)]. Here we review the structural understanding of the superdeformed and the hyperdeformed states of (36)Ar and present new results on the shape isomers as well. Special attention is paid to the clusterization of these states, which indicates the appropriate reaction channels for their formation.OTKA[K72357], HungaryFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq

Possible hyperdeformed band in (36)Ar observed in (12)C+(24)Mg elastic scattering

Fifteen strongly oscillating angular distributions of the elastic scattering of (12)C + (24)Mg at energies around the Coulomb barrier (E(c.m). = 10.67-16.00 MeV) are reproduced by adding five Breit-Wigner resonance terms to the l = 2, 4, 6, 7, and 8 elastic S matrix. The nonresonant, background elastic scattering S matrix S(l)(0) is calculated using the Sao Paulo potential. The J = 2, 4, 6, 7, and 8 (h) over bar molecular resonances fit well into a rotational molecular band, together with other higher lying resonances observed in the (16)O + (20)Ne elastic scattering. We propose that the presently observed, largely deformed molecular band corresponds to the hyperdeformed band, which has been found previously in alpha-cluster calculations, as well as in a new Nilsson model calculation. Systematic study of its possible clusterizations predicts the preference of the (12)C + (24)Mg and (16)O + (20)Ne molecular structure, in accordance with our present results.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)OTKA[K72357], Hungar

The (9)Be((8)Li, (9)Be)(8)Li elastic-transfer reaction

Angular distributions for the (9)Be((8)Li, (9)Be) (8)Li elastic-transfer reaction have been measured with a 27-MeV (8)Li radioactive nuclear beam. Spectroscopic factors for the <(9)Be vertical bar(8)Li + p > bound system were obtained from the comparison between the experimental differential cross sections and finite-range distorted-wave Born approximation calculations made with the code FRESCO. The spectroscopic factors so obtained are compared with shell-model calculations and other experimental values. Using the present value for the spectroscopic factors, cross sections and reaction rates for the (8)Li(p,gamma) (9)Be direct proton-capture reaction of astrophysical interest were calculated in the framework of the potential model.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo[FAPESP 2001/06676-9]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2006/00629-2]U. S. NSF National Science Foundation[PHY0354828]U. S. NSF National Science Foundation[INT03-05347]U. S. Department of Energy (DOE)[DE-FG02-08ER41533]U. S. Department of Energy (DOE)[DE-FC02-07ER41457]CONACY

Transfer reactions in the investigation of light-nuclei nucleosynthesis

Cross sections for the (6)Li(p,gamma)(7)Be, (7)Li(n,gamma)(8)Li (8)Li(n,gamma)(9)Li and (8)Li(p,gamma)(9)Be capture reactions have been investigated in the framework of the potential model. The main ingredients of the potential model are the potentials used to generate the continuum and bound-state wave functions and spectroscopic factors of the corresponding bound systems. The spectroscopic factors for the (7)Li circle times n=(8)Li(gs), (8)Li circle times n=(9)Li(gs) bound systems were obtained from a FR-DWBA analysis of neutron transfer reactions induced by (8)Li radioactive beam on a (9)Be target, while spetroscopic factor for the (8)Li circle times n=(9)Be(gs) bound system were obained from a proton transfer reaction. From the obtained capture reaction cross section, reaction rate for the (8)Li(n,gamma)(9)Li and (8)Li(p,gamma)(9)Be direct neutron and proton capture were determined and compared with other experimental and calculated values