Nuclear Theory·nucl-th

Wednesday·August 31, 2016

11 papers—9 primary·2 cross-listed

01
$α$ -induced reaction cross sections in the mass range $A \approx 20 - 50$ : a critical review
Peter Mohr
In a recent review it was shown that the cross sections of $α$ -induced reactions in the $A \approx 20 - 50$ mass range follow a general and smooth trend in most cases. For comparison of cross sections of different targets at various energies the method of reduced cross sections $σ_{red}$ and reduced energies $E_{red}$ was used. Four outliers were identified: $^{36}$ Ar and $^{40}$ Ar with unusally small cross sections and $^{23}$ Na and $^{33}$ S with unusually large cross sections. New data for $^{23}$ Na were presented at this NPA-7 conference; contrary to the previous data, these new data fit into the general systematics. In addition, a relation between the most effective energy $E_{0}$ for astrophysical reaction rates (the so-called Gamow window) and the reduced energy $E_{red}$ is presented.
nucl-thnucl-exJ.Phys.Conf.Ser.(2018)·2 citations
02
The Expectation Value of S(1).S(2)-Wave Functions Don't Matter
L. Zamick
We consider the expectation value of the quantity [3+ \sigma (1).\sigma (2)]/4 . This has a value +1 for 2 nucleons with spin S=1and zero for S=0. We show that for the jj coupling 2 particle configuration [j(1) j(2)]^{J} the expectation value has the structure A+B J(J+1) where A and B are constants. We then show that for a 2proton-2neutron configuration with total angular momentum I the expectation value per pair is independent of the details of the wave function and has a similar structure A' +B' I(I+1) with B'=B/6.
nucl-th0 citations
03
New concept for pairing anti-halo effect as a localized wave packet of quasi-particle
K. Hagino · H. Sagawa
The pairing anti-halo effect is a phenomenon that a pairing correlation suppresses a divergence of nuclear radius, which happens for single-particle states with orbital angular momenta of $l$ = 0 and 1 in the limit of vanishing binding energy. While this effect has mainly been discussed in terms of Hartree-Fock-Bogoliubov (HFB) theory, we here use a three-body model and provide its new intuitive concept as a localized wave packet for a quasi-particle, that is, a coherent superposition of a weakly bound and continuum wave functions due to a pairing interaction. We show that the one-particle density in the three-body model can be directly expressed with such quasi-particle wave functions, which have a close analog to wave functions in the HFB approximation.
nucl-thnucl-exPRC(2017)·6 citations
04
Systematic study of favored \alpha-decay half-lives of closed shell odd-A and doubly-odd nuclei related to ground and isomeric states
Xiao-Dong Sun · Ping Guo · Xiao-Hua Li
In this work, we systematically investigate the favored $α$ -decay half-lives and $α$ preformation probabilities of both odd- $A$ and doubly-odd nuclei related to ground and isomeric states around the doubly magic cores at $Z = 82$ , $N = 82$ and at $Z = 82$ , $N = 126$ , respectively, within a two-potential approach from the view of the valence nucleon (or hole). The results show that the $α$ preformation probability is linear related to $N_{p} N_{n}$ or $N_{p} N_{n} I$ , where $N_{p}$ , $N_{n}$ , and $I$ are the number of valence protons (or holes), the number of valence neutrons (or holes), and the isospin of the parent nucleus, respectively. Fitting the $α$ preformation probabilities data extracted from the differences between experimental data and calculated half-lives without a shell correction, we give two analytic formulas of the $α$ preformation probabilities and the values of corresponding parameters. Using those formulas and the parameters, we calculate the $α$ -decay half-lives for those nuclei. The calculated results can well reproduce the experimental data.
nucl-thnucl-exPRC(2016)·42 citations
05
Alpha-decay energies of superheavy nuclei for the Fayans functional
S. V. Tolokonnikov · I. N. Borzov · M. Kortelainen · Yu. S. Lutostansky · E. E. Saperstein
Alpha-decay energies for several chains of super-heavy nuclei are calculated within the self-consistent mean-field approach by using the Fayans functional FaNDF $^{0}$ . They are compared to the experimental data and predictions of two Skyrme functionals, SLy4 and SkM*, and of the macro-micro method as well. The corresponding lifetimes are calculated with the use of the semi-phenomenological formulas by Parkhomenko and Sobiczewski and by Royer and Zhang.
nucl-thEPJA(2017)·13 citations
06
From resonantly interacting fermions with effective range to neutron matter
Denis Lacroix🇫🇷
A density functional theory is proposed for strongly interacting fermions with arbitrary large negative scattering length. The functional has only two parameters that are directly fixed to reproduce the universal properties of unitary gas: the so-called "Bertsch parameter" $ξ_{0}$ and a parameter $η_{e}$ related to the possible influence of the effective range $r_{e}$ at infinite scattering length $a$ . Using most recent quantum Monte-Carlo (QMC) estimates of these two parameters, it is shown that the functional properly reproduces the experimental measurements of interacting Fermi systems not only at unitarity but also away from this limit over a wide range of $(a k_{F})^{- 1}$ values. The functional is applied to obtain an expression of the Tan's contact parameter including the effect of $r_{e}$ . Application is finally made to neutron matter. It is shown that most recent QMC results are well reproduced.
nucl-thcond-mat.quant-gasPRA(2016)·20 citations
07
Recent progress on superstrange dynamics
T. Gaitanos🇬🇷
We review the present activities related to hypernuclear production in hadronic in-medium reactions at intermediate energies. The status of theoretical predictions and experimental evidences for the in-medium formation of bound superstrange matter is discussed. Heavy-ion collisions and antiproton-induced reactions at energies close to strangeness production thresholds create the conditions of hypermatter formation. This allows to understand better in-medium hyperon interactions and sets constraints on the strangeness sector of the nuclear equation of state.
nucl-thIJMPE(2016)·2 citations
08
Comment on "No-core configuration-interaction model for the isospin- and angular-momentum-projected states" by Satuła, Baczyk, Dobaczewski, and Konieczka
I. Bentley · K. Neergård · S. Frauendorf
The authors state that results recently published by Carlsson and Toivanen "seem to contradict" the conclusions of some of our work. We show that this statement is based on a misinterpretation of the results of Carlsson and Toivanen.
nucl-th0 citations
09
Two-Particle Correlations in Heavy-Light Ion Collisions
Douglas E. Wertepny🇺🇸
We study the initial, high-energy scatterings in heavy ion collisions using the saturation/Color Glass Condensate framework. We focus on two-particle long-range rapidity correlations which are modeled as two-gluon correlations. We calculate the two-gluon production cross section using the saturation framework in the heavy-light ion regime, including all-order saturation effects in the heavy nucleus while considering only two-orders in the light ion. The two-gluon production cross section generates four types of long-range in rapidity correlations: (i) geometric correlations, (ii) Hanbury Brown and Twiss (HBT) like correlations accompanied by a back-to-back maximum, (iii) near-side correlations, and (iv) away-side azimuthal correlations. The geometric correlations (i) are due to the fact that nucleons are correlated by simply being confined within the same nucleus. Correlations (iii) and (iv) have exactly the same amplitudes along with azimuthal and rapidity shapes: one centered around $Δ ϕ = 0$ and the other one centered around $Δ ϕ = π$ (here $Δ ϕ$ is the azimuthal angle between the two produced gluons). The geometry dependence of the correlation function leads to stronger azimuthal near- and away-side correlations in the tip-on-tip U+U collisions than in the side-on-side U+U collisions, an exactly opposite behavior from the correlations generated by the elliptic flow of the quark-gluon plasma: a study of azimuthal correlations in the U+U collisions may help to disentangle the two sources of correlations. Finally we rewrite our result for the two-gluon production cross-section in a $k_{T}$ -factorized form resulting in an expression involving a convolution of one- and two-gluon Wigner distributions over the transverse momenta and impact parameters. This differs from the $k_{T}$ -factorized forms used in the literature.
nucl-thhep-phnucl-ex1 citation

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first authorsco-authorsvia INSPIRE