Two independent methods: Asymptotic Normalization Coefficients (ANC) and Modified Diffraction Model (MDM) were applied to new and existing experimental data to search for states with enhanced radii in isobaric analogue states (IAS) of 12 B and 12 N. The ANC analysis of the 11 B(d,p) 12 B reaction at E d = 21.5 MeV has confirmed neutron halo existence for two states of 12 B: 2 − , 1.67 MeV and 1 − , 2.62 MeV [1]. Some new results were obtained for higher excited states: halo-like states were observed for 0 + , 2.72 MeV and 3 − , 3.39 MeV states. It should be mentioned that the last one is unbound state, which is 19 keV above the neutron emission threshold and in both states last neutron has a non-zero orbital momentum (l n =1 and l n =2 correspondingly). We propose to use MDM to study isobaric analogue states of 12 B in the mirror 12 N nucleus and apply it to analyze the ( 3 He,t) reaction data. The existing in the literature data are not completed enough to make definite conclusion about halo in the 2 − and 1 − states of 12 N. This fact simulated us to carry out a new experiment on the 12 C( 3 He,t) 12 N reaction at the end of 2018. The measurements were conducted at the University of Jyväskylä (Finland) using the K130 cyclotron to produce a 3 He beam at E( 3 He)=40 MeV. The differential cross sections of the 12 C( 3 He,t) 12 N reaction were measured in the c.m. angular range 8°–70°. Preliminary results for angular distributions are obtained. MDM analysis of preliminary ( 3 He,t) experimental data is done.

The differential cross sections for the 12C(3He, t)12N reaction leading to formation of the 1+ (ground state), 2+ (0.96 MeV), 2− (1.19 MeV), and 1− (1.80 MeV) states of 12N are measured at E(3He) = 40 MeV. The analysis of the data is carried out within the modified diffraction model and distorted wave Born approximation. Increased rms radii have been obtained for the ground, 2− (1.19 MeV), and 1− (1.80 MeV) states. We revealed that 12B, 12N, and 12C in the isobaric analogue states with T = 1, and spin-parities 2− and 1− have increased radii and exhibit properties of neutron and proton halo states.

An experiment was done to search for states with a neutron halo in B-12. The measurements were carried out at the cyclotron of the University of Jyvaskyla (Finland) using Large Scattering Chamber (LSC). The idea of the work was to search for two states with the expected neutron halo, 1(-) and 2(-). Differential cross sections with excitation of B-12 states, including abovementioned states, were observed. The preliminary calculations on halo radii by the method of asymptotic normalization coefficients for the 2(-) and 1(-) states which are in a discrete spectrum gave following values: 5.6 fm and 7.4 fm, which is much larger than the radius of the valence neutron in the ground state. But strictly the presence of a neutron halo can be confirmed only for 1(-) state. The 2(-) state can be considered only as candidate for halo. An unexpected result was obtained for the 3(-), 3.39 MeV state, which is in continuum 19 keV above the decay threshold B-12 -> B-11 + n, preliminary estimation for its halo radius is similar to 6.5 fm. This indicates that the halo can be present in this state as well. But strict conditions for neutron halo are not fulfilled in the same way as for 2(-) state. Until now, the neutron halo in unbound states has been observed only for the members of the rotational bands.

We have measured the differential cross-sections for the elastic as well as inelastic scattering populating the 2.43[Formula: see text]MeV [Formula: see text] excited state in [Formula: see text] using [Formula: see text] beams at energies of 30, 40 and 47[Formula: see text]MeV on a [Formula: see text] target. The experimental results for the elastic scattering were analyzed within the framework of the optical model using the Woods–Saxon and double-folding potentials. The theoretical calculations for the concerned excited states were performed using the coupled-channel method. The optimal deformation parameters for the excited states of [Formula: see text] nucleus were extracted.

An experiment was done to search for states with a neutron halo in 12B. The measurements were carried out at the cyclotron of the University of Jyvaskyla (Finland) using Large Scattering Chamber (LSC). The idea of the work was to search for two states with the expected neutron halo, 1 ̄ and 2 ̄. Differential cross sections with excitation of 12B states, including abovementioned states, were observed. The preliminary calculations on halo radii by the method of asymptotic normalization coefficients for the 2 ̄ and 1 ̄ states which are in a discrete spectrum gave following values: 5.6 fm and 7.4 fm, which is much larger than the radius of the valence neutron in the ground state. But strictly the presence of a neutron halo can be confirmed only for 1 ̄ state. The 2 ̄ state can be considered only as candidate for halo. An unexpected result was obtained for the 3 ̄, 3.39 MeV state, which is in continuum 19 keV above the decay threshold 12B → 11B + n, preliminary estimation for its halo radius is ∼ 6.5 fm. This indicates that the halo can be present in this state as well. But strict conditions for neutron halo are not fulfilled in the same way as for 2 ̄ state. Until now, the neutron halo in unbound states has been observed only for the members of the rotational bands.

We present the results of measurements and analysis of the differential cross sections of the 11B(d, p)12B reaction leading to formation of the 1+ ground state and the 0.953-MeV 2+, 1.674-MeV 2−, 2.621-MeV 1−, 2.723-MeV 0+, 3.389-MeV 3− excited states of 12B at Ed = 21.5 MeV. The analysis of the data was carried out within the coupled-reaction-channels method for the direct neutron transfer and the Hauser-Feshbach formalism of the statistical compound-nucleus model. We deduced the spectroscopic factors, asymptotic normalization coefficients, and rms radii of the last neutron in all states studied. The existence of the neutron halos in the 1.674-MeV 2− and 2.621-MeV 1− states was found in consistence with the earlier published data. New information about the enlarged rms radii (6.5 fm) of the last neutron in the unbound 3.389-MeV 3− states of 12B was obtained, which may indicate the evidence of the neutron halo with the orbital momentum of the last neutron equal to two.

Differential cross-sections of the elastic and inelastic 13C + α scattering were measured at E(α) = 90 MeV. The root mean-square radii() of 13C nucleus in the states: 8.86 (1/2−), 3.09 (1/2+) and 9.90 (3/2−) MeV were determined by the Modified diffraction model (MDM). The radii of the first two levels are enhanced compared to that of the ground state of 13C, confirming the suggestion that the 8.86 MeV state is an analogue of the Hoyle state in 12C and the 3.09 MeV state has a neutron halo. Some indications to the abnormally small size of the 9.90 MeV state were obtained.

The study of inelastic scattering and multi-nucleon transfer reactions was performed by bombarding a 9Be target with a 3He beam at an incident energy of 30 MeV. Angular distributions for 9Be(3He,3He)9Be, 9Be(3He,4He)8Be, 9Be(3He,7Be)5He, 9Be(3He,6Li)6Li and 9Be(3He,7Li)5Li reaction channels were measured. Cross sections for channels leading to unbound 5Heg.s., 5Lig.s. and 8Be systems were obtained from singles measurements where the relationship between the energy and the scattering angle of the observed stable ejectile is constrained by two-body kinematics. Information on the cluster structure of 9Be was obtained from the transfer channels. It was concluded that cluster transfer is an important mechanism in the investigated nuclear reactions. In the present work an attempt was made to estimate the relative strengths of the interesting 8Be+n and 5He+α cluster configurations in 9Be. The branching ratios have been determined confirming that the 5He+α configuration plays an important role. The configuration of 9 Be consisting of two bound helium clusters 3He+6He is significantly suppressed, whereas the two-body configurations 8Be+n and 5He+α including unbound 8Be and 5He are found more probable.

A resonance-like structure in the excitation function for elastic and inelastic 14C + 12C interactions is investigated. Angular distributions for the 14C(12C,10Be)16O reaction at center-of-mass energies of 21.1, 23.5, and 24.6 MeV are obtained. It is shown that the angular distribution at the maximum cross section corresponds to the 12+ resonance and the 10Be + 16O structure. The position of the level with an angular momentum of 10+ is predicted.

The study of inelastic scattering and multi-nucleon transfer reactions was performed by bombarding a Be-9 target with a He-3 beam at an incident energy of 30 MeV. Angular distributions for Be-9(He-3, He-3) Be-9, Be-9(He-3, He-4) Be-8, Be-9(He-3, Be-7) He-5, Be-9(He-3, Li-6) Li-6 and Be-9(He-3, Li-7)(5) Li reaction channels were measured. Cross sections for channels leading to unbound He-5(g.s)., Li-5(g.s). and Be-8 systems were obtained from singles measurements where the relationship between the energy and the scattering angle of the observed stable ejectile is constrained by two- body kinematics. Information on the cluster structure of Be-9 was obtained from the transfer channels. It was concluded that cluster transfer is an important mechanism in the investigated nuclear reactions. In the present work an attempt was made to estimate the relative strengths of the interesting Be-8+n and He-5+alpha cluster configurations in Be-9. The branching ratios have been determined confirming that the He-5+alpha configuration plays an important role. The configuration of Be-9 consisting of two bound helium clusters He-3+He-6 is significantly suppressed, whereas the two- body configurations Be-8+n and He-5+alpha including unbound Be-8 and He-5 are found more probable.

Exotic Nuclei, pp. 73-88 (2015) No AccessPROPERTIES OF LIGHT NUCLEI BY INELASTIC SCATTERING AND NUCLEON TRANSFER IN 3,4He + 9Be REACTIONS AT LOW ENERGIESA. S. Denikin, S. M. Lukyanov, Yu. E. Penionzhkevich, N.K. Skobelev, Yu. G. Sobolev, E.I. Voskoboynik, W. H. Trzaska, G.P. Tyurin, J. Mrazek, V. Kroha, V. Burjan, Ś Piskoř, V. Glagolev, S. V. Khlebnikov, M. N. Harakeh and K. A. KuterbekovA. S. DenikinInternational University "Dubna", Dubna, 141980, Russian FederationFlerov Laboratory of Nuclear Reactions, Dubna, 141980, Russian Federation, S. M. LukyanovFlerov Laboratory of Nuclear Reactions, Dubna, 141980, Russian Federation, Yu. E. PenionzhkevichFlerov Laboratory of Nuclear Reactions, Dubna, 141980, Russian FederationNational Research Nuclear University MEPhI, Moscow, Russian Federation, N.K. SkobelevFlerov Laboratory of Nuclear Reactions, Dubna, 141980, Russian Federation, Yu. G. SobolevFlerov Laboratory of Nuclear Reactions, Dubna, 141980, Russian Federation, E.I. VoskoboynikFlerov Laboratory of Nuclear Reactions, Dubna, 141980, Russian Federation, W. H. TrzaskaUniversity of Jyväskylä, Department of Physics, Finland, G.P. TyurinUniversity of Jyväskylä, Department of Physics, Finland, J. MrazekNuclear Physics Institute ASCR, 250068 Řež, Czech Republic, V. KrohaNuclear Physics Institute ASCR, 250068 Řež, Czech Republic, V. BurjanNuclear Physics Institute ASCR, 250068 Řež, Czech Republic, Ś PiskořNuclear Physics Institute ASCR, 250068 Řež, Czech Republic, V. GlagolevNuclear Physics Institute ASCR, 250068 Řež, Czech Republic, S. V. KhlebnikovKhlopin Institute, St. Petersburg, Russian Federation, M. N. HarakehKernfysisch Versneller Instituut, University of Groningen, Groningen, Netherlands and K. A. KuterbekovEurasian Gumilev University, Astana, Kazakhstanhttps://doi.org/10.1142/9789814699464_0008Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: A study of inelastic scattering and single-particle transfer reactions was performed by alpha and 3He beams on a 9Be target at energy about 50 MeV. Angular distributions of the differential cross sections for the 9Be(α,α')9Be*, 9Be(α,3He)10Be, 9Be(α,t)10B, 9Be(3He,6Li)6Li and 9Be(3He,6Be)6He reactions were measured. Experimental angular distributions of the differential cross sections for the ground state and a few low-lying states were analyzed in the framework of the optical model, coupled channels and distorted-wave Born approximation. The information on the cluster structure of the reaction products are obtained. An analysis of the spectroscopic factors was performed. Keywords: HI elastic and inelastic scatteringTransfer reactionsCluster in light nucleiCoupled channelsDWBAOptical model FiguresReferencesRelatedDetails Exotic NucleiMetrics History KeywordsHI elastic and inelastic scatteringTransfer reactionsCluster in light nucleiCoupled channelsDWBAOptical modelPDF download

The angular distribution of the products of the 14C + 12C reaction at the energies E cm = 22.1, 23.5, and 24.6 MeV has been studied near a 23.5-MeV quasimolecular resonance. Channels with the yield of 8,9,10Be have been considered for various excitation energies of the residual nucleus. The results have been analyzed within the cluster and DWBA models. It has been shown that an approach based on the assumption of direct processes reproduces the features of the angular distributions. Oscillations corresponding to the formation of a quasimolecular resonance with an angular momentum of 12+ have been detected near the resonance.

The differential cross sections for elastic and inelastic 11B + α scattering were measured at the alpha-particle energy of 65 MeV, the inelastic-scattering processes leading to the excitation of known states of 11B up to excitation energies of about 14 MeV. Data on elastic scattering were analyzed together with those that were published earlier for lower energies. The cross sections for inelastic scattering were analyzed on the basis of the distorted-wave method. A modified diffractionmodel was used to determine the root-mean-square radii of excited states. The radii of states whose excitation energies were below about 7MeV were found to agree with radius of the ground state to within 0.1 to 0.15 fm. This result complieswith the traditional idea that the low-lying states of 11B have a shell structure. The possibility that these states belong to the predicted rotational bands, which, if any, are truncated to three states, cannot be ruled out either. The majority of the observed highly excited states are distributed among four rotational bands. The moments of inertia of these bands are close; for the band based on the 3/2− state at E* = 8.56 MeV, they are even higher than those of the Hoyle state in the 12C nucleus. The measured radii of states associated with these bands of 11B are larger than the ground-state radius by 0.7 to 1.0 fm and are also close to the radius of the Hoyle state. The results of the present study agree with the existing predictions that the cluster structure of the 11B nucleus is diverse at high excitation energies. The hypothesis that the 11B nucleus features a “giant” state of size commensurate with those in heavy nuclei was not confirmed.

A study of inelastic scattering and multi-particle transfer reactions was performed by alpha and 3He beams on a 9Be target at energy about 50 MeV. Angular distributions of the differential cross sections for the 9Be(α,α′)9Be*, 9Be(α,3He)10Be, 9Be(α,t)10B, 9Be(3He,6Li)6Li and 9Be(3He,6Be)6He reactions were measured. Experimental angular distributions of the differential cross sections for the ground state and a few low-lying states were analyzed in the framework of the optical model, coupled channels and distorted-wave Born approximation. The information on the cluster structure of the reaction products are obtained. An analysis of the obtained spectroscopic factors was performed.

The study of inelastic scattering and multi-nucleon transfer reactions was performed by bombarding a 9Be target with a 3He beam at an incident energy of 30 MeV. Angular distributions for 9Be(3He,3He)9Be, 9Be(3He,4He)8Be, 9Be(3He,7Be)5He, 9Be(3He,6Li)6Li and 9Be(3He,7Li)5Li reaction channels were measured. Cross sections for channels leading to unbound 5Heg.s., 5Lig.s. and 8Be systems were obtained from singles measurements where the relationship between the energy and the scattering angle of the observed stable ejectile is constrained by two-body kinematics. Information on the cluster structure of 9Be was obtained from the transfer channels. It was concluded that cluster transfer is an important mechanism in the investigated nuclear reactions. In the present work an attempt was made to estimate the relative strengths of the interesting 8Be+n and 5He+α cluster configurations in 9Be. The branching ratios have been determined confirming that the 5He+α configuration plays an important role. The configuration of 9 Be consisting of two bound helium clusters 3He+6He is significantly suppressed, whereas the two-body configurations 8Be+n and 5He+α including unbound 8Be and 5He are found more probable.

A study of inelastic scattering and multi-particle transfer reactions was performed by alpha and 3 He beams on a 9 Be target at energy about 50 MeV. Angular distributions of the differential cross sections for the 9 Be(α,α′) 9 Be*, 9 Be(α, 3 He) 10 Be, 9 Be(α,t) 10 B, 9 Be( 3 He, 6 Li) 6 Li and 9 Be( 3 He, 6 Be) 6 He reactions were measured. Experimental angular distributions of the differential cross sections for the ground state and a few low-lying states were analyzed in the framework of the optical model, coupled channels and distorted-wave Born approximation. The information on the cluster structure of the reaction products are obtained. An analysis of the obtained spectroscopic factors was performed.

A. S. Denikin a, b, , S. M. Lukyanov , N. K. Skobelev , Yu.G. Sobolev , E. I. Voskoboynik , Yu. E. Penionzhkevich b, , W. H. Trzaska , G. P. Tyurin , V. Burjan , V. Kroha , J. Mr azek , S. Pisko r , V. Glagolev , Yi Xu , S. V. Khlebnikov f , M.N. Harakeh , K. A. Kuterbekov h, , Yu. Tuleushev i a International University ©Dubnaa, Dubna, Russia b Joint Institute for Nuclear Research, Dubna c National Research Nuclear University MEPhI, Moscow d Department of Physics, University of Jyvéaskyléa, Jyvéaskyléa, Finland e Nuclear Physics Institute, Re z, Czech Republic f Khlopin Institute, St. Petersburg, Russia g Kernfysisch Versneller Instituut, University of Groningen, Groningen, Netherlands h Eurasian Gumilev University, Astana i Nuclear Physics Institute, Almaty, Kazakhstan