$α$ decaying states of $^{44, 46, 52}$Ti were investigated with angular correlation functions between $t$ and $α$ with the $^{40, 42, 48}$Ca($^7$Li, $tα$)$^{40, 42, 48}$Ca reactions at E = 26.0 MeV. Many $α$ cluster states were newly observed in the 10 - 15 MeV excitation energy of $^{44}$Ti and their spin-parities were assigned, in which $J^π=7^-$ state was found at 11.95 MeV as a candidate for the member of the $K=0_1^-$ negative parity band. In $^{46}$Ti many $α$ cluster states were also found in the 11 - 17 MeV excitation energy with the $^{42}$Ca($^7$Li, $tα$)$^{42}$Ca reaction, though its strength is weak compared to $^{44}$Ti. No $α$ cluster states were detected for the $^{48}$Ca($^7$Li, $tα$)$^{48}$Ca reaction, in which the number of coincidence events decaying from $^{48}$Ca was very small.
In a measurement of the 9Be(7Li,alpha 7Li)n alpha reaction at E = 52 MeV it is unambigously established for the first time that the 9Be excited states around 6.5 and 11.3 MeV decay into the alpha + 5He channel. This fact may support previous claims that the 11.3 MeV state is also a member of the ground state rotational band.
The effects of cluster correlations have been studied in the $^{12}$C + $^{12}$C reaction at 50 MeV/nucleon, using three AMD models, the AMD (AMD/D) without any additional cluster correlations, AMD/D-COALS with nucleon correlations based on a coalescence prescription for light cluster formations with $A\leq4$ and AMD-Cluster with an extended cluster correlation in two-nucleon collision processes and a special treatment for intermediate fragment formation with A $\le 9$. The angular distributions and energy spectra of fragments have been simulated and compared with the available experimental da…
Dissipative 12C+12C reactions at 95 MeV are fully detected in charge with the GARFIELD and RCo apparatuses at LNL. A comparison to a dedicated Hauser-Feshbach calculation allows to select events which correspond, to a large extent, to the statistical evaporation of highly excited 24Mg, as well as to extract information on the isotopic distribution of the evaporation residues in coincidence with their complete evaporation chain. Residual deviations from a statistical behaviour are observed in αyields and attributed to the persistence of cluster correlations well above the 24Mg threshold for 6 α…
The lattice QCD analysis of the HAL QCD Collaboration has recently derived $ΩN$ and $ΩΩ$ interacting potentials with nearly physical quark masses ($m_π\simeq $ 146 MeV and $m_K \simeq $ 525 MeV). They found an attractive interaction in the $ΩN$ $^5S_2$ channel which supports a bound state with a central binding energy of 1.54 MeV. The $ΩΩ$ $^1S_0$ channel shows an overall attraction with a bound state with a central binding energy of 1.6 MeV. In this paper we looked closely at the $ΩNN$ and $ΩΩN$ three-body systems making use of the latest HAL QCD Collaboration $ΩN$ and $ΩΩ$ interactions. Our …
We analyze if the nucleon structure of the $α$ decaying nucleus can be visible in the experimental bremsstrahlung spectra of the emitted photons which accompany such a decay. We develop a new formalism of the bremsstrahlung model taking into account distribution of nucleons in the $α$ decaying nuclear system. We conclude the following: (1) After inclusion of the nucleon structure into the model the calculated bremsstrahlung spectrum is changed very slowly for a majority of the $α$ decaying nuclei. However, we have observed that visible changes really exist for the $^{106}{\rm Te}$ nucleus ($Q_…
A study of the 7Li(9Be,4He 10Be)2H reaction at E{beam}=70 MeV has been performed using resonant particle spectroscopy techniques and provides the first measurements of alpha-decaying states in 14C. Excited states are observed at 14.7, 15.5, 16.4, 18.5, 19.8, 20.6, 21.4, 22.4 and 24.0 MeV. The experimental technique was able to resolve decays to the various particle bound states in 10Be, and provides evidence for the preferential decay of the high energy excited states into states in 10Be at ~6 MeV. The decay processes are used to indicate the possible cluster structure of the 14C excited state…
Isoscalar monopole strength function in $^{16}$O up to $E_{x}\simeq40$ MeV is discussed. We found that the fine structures at the low energy region up to $E_{x} \simeq 16$ MeV in the experimental monopole strength function obtained by the $^{16}$O$(α,α^{\prime})$ reaction can be rather satisfactorily reproduced within the framework of the $4α$ cluster model, while the gross three bump structures observed at the higher energy region ($16 \lesssim E_{x} \lesssim 40$ MeV) look likely to be approximately reconciled by the mean-field calculations such as RPA and QRPA. In this paper, it is emphasize…
On the base of potential theory of light nuclei cluster photodisintegration the characteristics of Lithium nuclei cluster photodisintegration reactions are considered in the range of low and intermediate energies. For the inverse reaction the interference has an opposite character: in forward semisphere it is deconstructive, and in backward semisphere it is constructive. In the energy range above several MeV the E2-multipole becomes dominating. The effect of appearance of the node structure of the wave function of relative motion has been considered in the characteristics of Li cluster photodi…
The experimentally available angular distributions (ADs) for 6,7Li and 20Ne ions elastically scattered from a 24Mg target are reanalyzed using various nuclear potentials based on phenomenological and microscopic approaches. The ADs for the 6Li + 24Mg system at energies Elab = 20, 88, and 240 MeV are considered, as are the ADs for the 7Li + 24Mg system at Elab = 20, 34, and 88 MeV, and the ADs for the 20Ne + 24Mg systems at Elab = 50, 60, 80, 90, and 100 MeV. Special emphasis is placed on the (d + α) and (t + α) cluster structures of 6Li and 7Li weakly bound projectiles, which appear at relativ…
A phenomenological model, proposed for the Kaonic Nuclear Cluster (KNC) K^-pp, is applied to the theoretical analysis of the KNC K^-pnn (or S^0). The theoretical values of the binding energy and the width are equal to epsilon_(S^0) = - 197 MeV and Gamma_(S^0) = 16 MeV. They agree well with the experimental data epsilon^(exp)_(S^0) = - 194.0(+ 1.5/- 4.4) MeV and Gamma^(exp)_(S^0) < 21 MeV} (PLB 597, 263 (2004)) and the theoretical values epsilon_(S^0) = - 191 MeV and Gamma_(S^0) = 13 MeV, obtained by Akaishi and Yamazaki within the potential model approach.
We compute energy distributions of three particles emerging from decaying many-body resonances. We reproduce the measured energy distributions from decays of two archetypal states chosen as the lowest $0^{+}$ and $1^{+}$-resonances in $^{12}$C populated in $β$-decays. These states are dominated by sequential, through the $^{8}$Be ground state, and direct decays, respectively. These decay mechanisms are reflected in the ``dynamic'' evolution from small, cluster or shell-model states, to large distances, where the coordinate or momentum space continuum wavefunctions are accurately computed.
The characteristics of fragment emission in peripheral $^{197}$Au+$^{197}$Au collisions 35 MeV/A are studied using the two clusterization approaches within framework of \emph{quantum molecular dynamics} model. Our model calculations using \emph{minimum spanning tree} (MST) algorithm and advanced clusterization method namely \emph{simulated annealing clusterization algorithm} (SACA) showed that fragment structure can be realized at an earlier time when spectators contribute significantly toward the fragment production even at such a low incident energy. Comparison of model predictions with expe…
A molecule model is proposed for the description of the properties of the kaonic nuclear cluster (KNC) anti-KNN with the structure N(ant-KN)_(I = 0) and quantum numbers I(J^P) = 1/2(0^-), the large binding energy B^(\exp)_(anti-KNN) = 103(6) MeV and the width Gamma^(\exp)_(anti-KNN) = 118(13) MeV, observed recently by the DISTO Collaboration. The theoretical values of the binding energy B^(th)_(anti-KNN) = 118 MeV, the width Gamma^(th)_(anti-KNN) = 142 MeV of the KNC anti-KNN and the density n_(anti-KNN) = 2.71 n_0, where n_0= 0.17 fm^(-3) is the normal nuclear density, reproduce well the larg…
Background The nuclear structure of the cluster bands in $^{20}$Ne presents a challenge for different theoretical approaches. It is especially difficult to explain the broad 0$^+$, 2$^+$ states at 9 MeV excitation energy. Simultaneously, it is important to obtain more reliable experimental data for these levels in order to quantitatively assess the theoretical framework. Purpose To obtain new data on $^{20}$Ne $α$ cluster structure. Method Thick target inverse kinematics technique was used to study the $^{16}$O+$α$ resonance elastic scattering and the data were analyzed using an \textit{R} mat…
Angular distributions of differential cross sections for the interaction of $K^{+}$ mesons with $^{^{12}}$C nucleus at beam momenta of 635, 715, and 800 MeV/c have been analyzed using 3$α$-particle model of $^{^{12}}$C. Differential cross sections for inelastic transitions to the (2$^{^{+}}$; 4.44 MeV) and (3$^{-}$; 9.64 MeV) states in $^{^{12}}$C are calculated, and deformation lengths $δ_{2}$ and $δ_{3}$ are extracted and consistent with other works. Good agreement with experimental data of elastic and inelastic $K^{\pm}$-$^{12}$C scattering is obtained.
Recently an alpha-cluster model based on the pn-pair interactions with using the isospin invariance of nuclear force has been proposed. According to the model the excess neutron pairs fill out the free space in the core determined by the difference in the charge and matter radii of the alpha-clusters. Then the number of excess neutrons in beta-stable nuclei depends on the number of the core alpha-clusters. In such a representation the specific density of binding energy of core is the only parameter to fit the experimental binding energies of beta-stable nuclei and it turned out to be a constan…
The structure of the isodoublet hypernuclei, $^{10}_Λ$B and $^{10}_Λ$Be within the framework of an $α+α+Λ+N$ four-body cluster model is studied. Interactions between the constituent subunits are determined so as to reproduce reasonably well the observed low-energy properties of the $αα$, $αN$, $αΛ$, $ααΛ$ and $ααN$ subsystems. Furthermore, the two-body $ΛN$ interaction is adjusted so as to reproduce the $0^+$-$1^+$ splitting of $^4_Λ$H. The $Λ$ binding energies of $^{10}_Λ$B and $^{10}_Λ$Be are 8.76 MeV and 8.94 MeV, respectively. The energy splitting of the $1^-$-$2^-$ levels in $^{10}_Λ$B is…
We point out an intriguing possibility that there exist topological soliton-like excitations in nuclei with $α$ cluster condensation. The excitations are vortices in superfluid, a property possessed by such Bose condensed nuclei. We show that the vortex-like states possess quantum numbers $J^{P}=n^{(-1)^n}$ and energies $\sim $ several MeV, measured from the ground state energies of the $n α$ condensed states. We point out actual candidates, for instance, $2^{+}(3 {MeV})$ for $^{8}$Be, $3^{-}(9.6 {MeV})$ for $^{12}$C, etc, although the topological nature as a vortex is obscure in such light nu…
We investigated cluster and toroidal aspects of isoscalar dipole excitations in $^{12}$C based on the shifted basis antisymmetrized molecular dynamics combined with the generator coordinate method, which can describes 1p-1h excitations and $3α$ dynamics. In the $E=10-15$ MeV region, we found two low-energy dipole modes separating from the giant dipole resonance. One is the developed $3α$-cluster state and the other is the toroidal dipole mode. The cluster state is characterized by the large amplitude cluster motion beyond the 1p-1h model space, whereas the toroidal dipole mode is predominantly…
The H dihyperon (DH) is studied in the framework of the SU(3) chiral quark model. It is shown that except the $σ$ chiral field, the overall effect of the other SU(3) chiral fields is destructive in forming a stable DH. The resultant mass of DH in a three coupled channel calculation is ranged from 2225 $MeV$ to 2234 $MeV$.
We analyse the properties of the kaonic nuclear cluster (KNC) anti-KNN with the structure Nx(anti-KN)_(I = 0), having the quantum numbers I(J^P) = 1/2(0^-), and treated as a quasi-bound hadronic molecule state. We describe the properties of the hadronic molecule, or the KNC Nx(anti-KN)_(I = 0), in terms of vibrational degrees of freedom with oscillator wave functions and chiral dynamics. These wave functions, having the meaning of trial wave functions of variational calculations, are parameterised by the frequency of oscillations of the (anti-KN)_(I = 0) pair, which is fixed in terms of the bi…
Effects of light-cluster degrees of freedom on collective flows in heavy-ion collisions at FOPI energies
Shanghai Jiao Tong University（上海交通大学）；Henan Normal University（河南师范大学）；East China Normal University（华东师范大学）；Sun Yat-sen University（中山大学）；Henan Academy of Science（河南省科学院）；Fudan University（复旦大学）
New calculations of the quasi-bound state positions in $K^{-}K^{-}pp$ kaonic nuclear cluster are performed using non-relativistic four-body Faddeev-type equations in AGS form. The corresponding separable approximation for the integral kernels in the three- and four-body kaonic clusters is obtained by using the Hilbert-Schmidt expansion procedure. Different phenomenological models of $\bar{K}N-πΣ$ potentials with one- and two-pole structure of $Λ$(1405) resonance and separable potential models for $\bar{K}$-$\bar{K}$ and nucleon-nucleon interactions, are used. The dependence of the resulting fo…
The prototype of a Kbar nuclear cluster, K^-pp, has been investigated using effective KbarN potentials based on chiral SU(3) dynamics. Variational calculation shows a bound state solution with shallow binding energy B(K^-pp)=20 \pm 3 MeV and broad mesonic decay width Γ(KbarNN -> πY N)=40 - 70 MeV. The KbarN(I=0) pair in the K^-pp system exhibits a similar structure as the Λ(1405). We have also estimated the dispersive correction, p-wave KbarN interaction, and two-nucleon absorption width.
