Nuclear Theory·nucl-th

Wednesday·August 31, 2016

11 papers—9 primary·2 cross-listed

01
[Submitted on 29 Aug 2016]
$α$ -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.
Comments:
4 pages, 2 figures, Proc. NPA7, York, 2015; J. Phys. Conf. Series, in print
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1608.08233 [pdf]
J.Phys.Conf.Ser.(2018)·2 citations
02
[Submitted on 29 Aug 2016]
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.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1608.08272 [pdf]
0 citations
03
[Submitted on 30 Aug 2016]
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.
Comments:
6 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1608.08312 [pdf]
PRC(2017)·6 citations
04
[Submitted on 30 Aug 2016]
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.
Comments:
9 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1608.08383 [pdf]
PRC(2016)·42 citations
05
[Submitted on 30 Aug 2016]
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.
Comments:
LaTeX, 12 pages, 2 figures, submitted to EPJA
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1608.08405 [pdf]
EPJA(2017)·13 citations
06
[Submitted on 30 Aug 2016]
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.
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas)
arXiv:
1608.08411 [pdf]
PRA(2016)·20 citations
07
[Submitted on 30 Aug 2016]
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.
Comments:
31 pages, 19 figures, International Journal of Modern Physics E (in press)
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1608.08494 [pdf]
IJMPE(2016)·2 citations
08
[Submitted on 30 Aug 2016]
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.
Comments:
This comment was submitted to Physical Review C. The editors chose to invite an erratum from Satula et al
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1608.08615 [pdf]
0 citations
09
[Submitted on 30 Aug 2016]
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.
Comments:
161 pages, 38 figures, Ph.D. dissertation
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1608.08618 [pdf]
1 citation
10
[Submitted on 30 Aug 2016] (cross-list from hep-ph)
The influence of chiral chemical potential, parallel electric and magnetic fields on the critical temperature of QCD
M. Ruggieri🇨🇳 · Z. Y. Lu🇨🇳 · G. X. Peng🇨🇳
We study the influence of external electric, $E$ , and magnetic, $B$ , fields parallel to each other, and of a chiral chemical potential, $μ_{5}$ , on the chiral phase transition of Quantum Chromodynamics. Our theoretical framework is a Nambu-Jona-Lasinio model with a contact interaction. Within this model we compute the critical temperature of chiral symmetry restoration, $T_{c}$ , as a function of the chiral chemical potential and field strengths. We find that the fields inhibit and $μ_{5}$ enhances chiral symmetry breaking, in agreement with previous studies.
Comments:
11 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1608.08310 [pdf]
PRD(2016)·32 citations
11
[Submitted on 30 Aug 2016] (cross-list from hep-th)
Anomalous transport from holography: Part I
Yanyan Bu🇮🇱 · Michael Lublinsky🇮🇱 · Amir Sharon🇮🇱
We revisit the transport properties induced by the chiral anomaly in a charged plasma holographically dual to anomalous $U (1)_{V} \times U (1)_{A}$ Maxwell theory in Schwarzschild- $A d S_{5}$ . Off-shell constitutive relations for vector and axial currents are derived using various approximations generalising most of known in the literature anomaly-induced phenomena and revealing some new ones. In a weak external field approximation, the constitutive relations have all-order derivatives resummed into six momenta-dependent transport coefficient functions: the diffusion, the electric/magnetic conductivity, and three anomaly induced functions. The latter generalise the chiral magnetic and chiral separation effects. Nonlinear transport is studied assuming presence of constant background external fields. The chiral magnetic effect, including all order nonlinearity in magnetic field, is proven to be exact when the magnetic field is the only external field that is turned on. Non-linear corrections to the constitutive relations due to electric and axial external fields are computed.
Comments:
v1: 42 pages, 10 multi-figures, 3 appendices; v2: minor corrections introduced and a few refs added
Subjects:
High Energy Physics — Theory (hep-th); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1608.08595 [pdf]
JHEP(2016)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE