The European Physical Journal A最新文献

(^{180})Hg is experimentally found to fission asymmetrically. This result was not expected as a naive fragment shell effects study would support the symmetric mode to be the most probable. In the present study we investigate both symmetric and asymmetric (^{180})Hg fission modes at the mean field level using various multipole moment constraints. Potential energy surfaces are analysed in terms of shell effects that shape their topographies and connections to fragment shell effects are made. The non-occurrence of low energy symmetric fission is interpreted in terms of (^{90})Zr fragment properties. Throughout this study a comparison with (^{264})Fm and its symmetric doubly magic (^{132})Sn fission fragments is done.

We present results from an experiment dedicated to measure the lifetimes of the low-lying excited states of ²⁰⁵Bi. This nucleus was studied in the one-proton transfer reaction ²⁰⁴Pb(¹⁶O,¹⁵N)²⁰⁵Bi and the lifetimes of the (11/2^-_1), (7/2^-_1), (5/2^-_1), (7/2^-_2) states were determined by utilizing the Recoil Distance Doppler Shift method. Upon comparing the results with the expectations of the particle-core coupling model, it indicates a low quadrupole collectivity in the structure of these states.

Several refined prompt emission model codes, nowadays employed, use the partition of total excitation energy (TXE) according to the temperature ratio R_T = T_L/T_H of fully accelerated fragments. In such codes R_T is given as input, either as an unique value for all fragmentations or as a function of A_H; This temperature ratio R_T being obtained by fitting the experimental ν(A) data with the respective prompt emission model code. This paper proposes a method for obtaining “experimental R_T(A_H)” (also based on experimental ν(A)), but without resorting to prompt emission model calculations for the fit of ν(A) data. So that this is an independent method providing R_T(A_H) which can be employed by any prompt emission model code in which the TXE partition is done at the full acceleration according to R_T given as input. A procedure which facilitates the parameterization of R_T(A_H) is proposed, too. A prediction of the R_T(A_H) shape at very high excitation energies of the fissioning nucleus is also reported. The comparison of R_T(A_H) ratios obtained from any TXE partition based on modeling at scission with those provided by the present method can constitute a supplementary validation of the respective modeling at scission.

We calculate the spectroscopic parameters of resonance X(4630) observed in the process (B^{+}rightarrow J/Psi phi K^{+}) by at the LHCb experiments at CERN by means of thermal QCD sum rule method at non-zero temperature. The exotic vector X(4630) is assigned as the diquark–antidiquark state ([cs][overline{cs}]) with spin-parity (J^{PC}=1^{-+}). Employing the two-point QCD sum rule approach up to the sixth order of the operator dimension by including non-perturbative contribution, we calculate the mass and decay constant of X(4630) at (Tne 0). The numerical analyses demonstrate that the values of the mass and decay constant of X(4630) near the deconfinement temperature decrease up to (9.8%) and (60%) of their vacuum values. At (Trightarrow 0), the obtained results for the mass (m_{X(4630)}=(4649pm 40)) MeV and decay constant (lambda _{X(4630)}=(10.07pm 0.8)times 10^{-3} ) MeV are in excellent agreement with the results reported by LHCb experiments and other theoretical predictions.

The nuclei lying in the vicinity of the proton drip line are proton emitters. A systematic analysis of the half-life of one proton emitter was estimated using the Effective Liquid Drop Model. We have exploited various mass tables say AME2020, WS4+RBF, FRDM, and KTUY in evaluating the Q-values. The half-lives obtained using various mass tables are compared with experimental values. Among the theoretical mass tables, WS4 is found to have less deviation in the prediction of the half-lives of one proton emission. Alpha-decay half-lives are also estimated to determine which decay mode dominates in the selected isotopes. Geiger–Nutall plots have been plotted and the linear nature of the graph has been successfully reproduced for all the mass tables. The New Geiger–Nuttal law, which illustrates the angular momentum dependency on half-life, also reproduces the linear nature of the graph.

This Topical Collection of the European Physics Journal A is devoted to recent progress in the nuclear many-body problem. In particular, it aims at a comprehensive compilation of developments related to the work of a pioneer in that field, Peter Schuck, who passed away in 2022. Together with Peter Ring, he co-authored the book on “The Nuclear Many-Body Problem”. Different concepts presented in this seminal book have been elaborated further within a broad international collaboration. For instance, the quasi-particle approaches in connection with nuclear superfluidity and cluster formation in nuclear systems, in particular alpha-particle condensation and quartetting at subsaturation densities, have been put forward inspired by Peter Schuck. These advances obtained in the nuclear many-body problem can also be applied to other systems, for instance solid state physics. This Topical Collection is considered as addendum and continuation of the textbook of P. Ring and P. Schuck.

Superfluid dilute neutron matter and ultracold gas, close to the unitary regime, exhibit several similarities. Therefore, to a certain extent, fermionic ultracold gases may serve as emulators of dilute neutron matter, which forms the inner crust of neutron stars and is not directly accessed experimentally. Quantum vortices are one of the most significant properties of neutron superfluid, essential for comprehending neutron stars’ dynamics. The structure and dynamics of quantum vortices as a function of pairing correlations’ strength are being investigated experimentally and theoretically in ultracold gases. Certain aspects of these studies are relevant to neutron stars. We provide an overview of the characteristics of quantum vortices in s-wave-type fermionic and electrically neutral superfluids. The main focus is on the dynamics of fermionic vortices and their intrinsic structure.

The scissors mode is investigated in the actinide region, including even–even superheavy nuclei up to (^{256})No, within the Time Dependent Hartree–Fock–Bogoliubov (TDHFB) approach. The solution of TDHFB equations by the Wigner Function Moments method predicts a splitting of the scissors mode into three intermingled branches due to spin degrees of freedom. Both the calculated energy centroid and integrated M1 strength in (^{254})No are in good agreement with the results of recent measurements performed by the Oslo method. The energy centroids and summed B(M1) values for other transuranium nuclides are predicted.

We aim to explore the bubble nature of the exotic nucleus ( ^{20})N within the microscopic antisymmetrized molecular dynamics (AMD) approach. Constraining its structural parameters, we analyse its static properties. Subsequently, we use the AMD infused finite range distorted wave Born approximation theory to calculate the Coulomb breakup of ( ^{20})N as an indirect approach to estimate the ( ^{19})N((n,gamma )^{20})N radiative capture rate.

Whether for fundamental studies or nuclear data evaluations, first-principle calculations of atomic nuclei constitute the path forward. Today, performing ab initio calculations (a) of heavy nuclei, (b) of doubly open-shell nuclei or (c) with a sub-percent accuracy is at the forefront of nuclear structure theory. While combining any two of these features constitutes a major challenge, addressing the three at the same time is currently impossible. From a numerical standpoint, these challenges relate to the necessity to handle (i) very large single-particle bases and (ii) mode-6, i.e. three-body, tensors (iii) that must be stored repeatedly. Performing second-order many-body perturbation theory(ies) calculations based on triaxially deformed and superfluid reference states of doubly open-shell nuclei up to mass (A=72), the present work achieves a significant step forward by addressing challenge (i). To do so, the memory and computational cost associated with the handling of large tensors is scaled down via the use of tensor factorization techniques. The presently used factorization format is based on a randomized singular value decomposition that does not require the computation and storage of the very large initial tensor. The procedure delivers an inexpensive and controllable approximation to the original problem, as presently illustrated for calculations that could not be performed without tensor factorization. With the presently developed technology at hand, one can envision to perform calculations of yet heavier doubly open-shell nuclei at sub-percent accuracy in a foreseeable future.