Nuclear Theory·nucl-th

Monday·April 25, 2016

10 papers—7 primary·3 cross-listed

01
[Submitted on 21 Apr 2016]
Update on nuclear structure effects in light muonic atoms
Oscar Javier Hernandez🇨🇦 · Nir Nevo Dinur🇨🇦 · Chen Ji🇨🇦 · Sonia Bacca🇨🇦 · Nir Barnea🇮🇱
We present calculations of the nuclear structure corrections to the Lamb shift in light muonic atoms, using state-of-the-art nuclear potentials. We outline updated results on finite nucleon size contributions.
Comments:
4 pages, 1 figure, Proceedings of the SSP 2015 conference
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1604.06496 [pdf]
Hyperfine Interact.(2016)·18 citations
02
[Submitted on 22 Apr 2016]
Luneburg-lens-like universal structural Pauli attraction in nucleus-nucleus interactions: origin of emergence of cluster structures and nuclear rainbows
Shigeo Ohkubo
The Pauli exclusion principle plays an important role in many-body fermion systems preventing them from collapsing by repulsion. For example, the Pauli principle causes a repulsive potential at short distances between two $α$ particles. On the other hand, the existence of nuclear rainbows demonstrates that the inter-nuclear potential is sufficiently attractive in the internal region to cause refraction. The two concepts of repulsion and attraction are seemingly irreconcilable. Contrary to traditional understanding, it is shown that the Pauli principle causes a {\it universal structural Pauli attraction} between nuclei rather than a {\it structural repulsive core}. Through systematic studies of $α$ + $α$ , $α$ + $^{16}$ O, $α$ + $^{40}$ Ca and $^{16}$ O+ $^{16}$ O systems, it is shown that the emergence of cluster structures near the threshold energy at low energies and nuclear rainbows at high energies is a direct consequence of the Pauli principle.
Comments:
6 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1604.06528 [pdf]
PRC(2016)·13 citations
03
[Submitted on 22 Apr 2016]
From dilute matter to the equilibrium point in the energy--density--functional theory
C.J. Yang🇫🇷 · M. Grasso🇫🇷 · D. Lacroix🇫🇷
Due to the large value of the scattering length in nuclear systems, standard density--functional theories based on effective interactions usually fail to reproduce the nuclear Fermi liquid behavior both at very low densities and close to equilibrium. Guided on one side by the success of the Skyrme density functional and, on the other side, by resummation techniques used in Effective Field Theories for systems with large scattering lengths, a new energy--density functional is proposed. This functional, adjusted on microscopic calculations, reproduces the nuclear equations of state of neutron and symmetric matter at various densities. Furthermore, it provides reasonable saturation properties as well as an appropriate density dependence for the symmetry energy.
Comments:
4 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1604.06587 [pdf]
PRC(2016)·34 citations
04
[Submitted on 22 Apr 2016]
Pairing effects on neutrino transport in low-density stellar matter
S. Burrello · M. Colonna · F. Matera
We investigate the impact of pairing correlations on neutrino transport in stellar matter. Our analysis is extended to nuclear matter conditions where large density fluctuations develop, associated with the onset of the liquid-vapor phase transition, and clustering phenomena occur. Within a thermodynamical treatment, we show that at moderate temperatures, where pairing effects are still active, the scattering of neutrinos in the nuclear medium is significantly affected by pairing correlations, which increase the neutrino trapping, thus modifying the cooling mechanism, by neutrino emission, of neutron stars.
Comments:
5 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1604.06642 [pdf]
PRC(2016)·14 citations
05
[Submitted on 22 Apr 2016]
On Single Particle Energies and Nuclear g Factors
Shadow Robinson · Larry Zamick
If we add one neutron to doubly magic ^{100}Sn, we can associate the low lying states in^{101} Sn with single particle states.The the J=5/2^{+} and J= 7/2^{+} states are identified as d_{5/2}and g_{7/2}states respectively...They are separated by an energy of 0.18 MeV.Unfortunately there is a disputeas to the ordering of these states.We examine how the 2 scenarios-- J=5/2^{+} ground state or J=7/2^{+}ground state-- affect spectra of higher Sn isotopes .
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1604.06698 [pdf]
IJMPE(2017)·2 citations
06
[Submitted on 22 Apr 2016]
Octupole correlations in the nucleus $^{144}$ Ba described with symmetry conserving configuration mixing calculations
Rémi N. Bernard · Luis M. Robledo · Tomás R. Rodríguez
We study the interplay of quadrupole and octupole degrees of freedom in the structure of the isotope $^{144}$ Ba. A symmetry conserving configuration mixing method (SCCM) based on a Gogny energy density functional (EDF) has been used. The method includes particle number, parity and angular momentum restoration as well as axial quadrupole and octupole shape mixing within the generator coordinate method. Predictions both for excitation energies and electromagnetic transition probabilities are in good agreement with the most recent experimental data.
Comments:
6 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1604.06706 [pdf]
PRC(2016)·53 citations
07
[Submitted on 22 Apr 2016]
Neutron capture reactions relevant to s-process and p-process in the domain of the $N = 50$ shell closure
Saumi Dutta · G. Gangopadhyay · Abhijit Bhattacharyya
Radiative thermal neutron capture cross sections for nuclei participating in s-process and p-process nucleosynthesis in and around $N = 50$ closed neutron shell have been calculated in statistical semi-microscopic Hauser-Feshbach approach for the energy range of astrophysical interest. A folded optical model potential is constructed utilizing the standard DDM3Y real nucleon-nucleon interaction. The folding of the interaction with target radial matter densities, obtained from the relativistic-mean-field approach, is done in coordinate space using the spherical approximation. The standard nuclear reaction code TALYS1.8 is used for cross-section calculation. The cross sections are compared with experimental results and reasonable agreements are found for almost all cases. Maxwellian-averaged cross sections (MACS) for the nuclei are presented at a single thermal energy of 30 keV relevant to s-process. We have also presented the MACS values over a range of energy from 5 to 100 keV for neutron magic nuclei with $(N = 50)$ .
Comments:
16 pages, 10 figures, 4 tables
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
1604.06757 [pdf]
PRC(2016)·9 citations
08
[Submitted on 22 Apr 2016] (cross-list from hep-ph)
Exploring universality of transversity in proton-proton collisions
Marco Radici🇮🇹 · Alessandro M. Ricci🇮🇹 · Alessandro Bacchetta🇮🇹 · Asmita Mukherjee🇮🇳
We consider the azimuthal correlations of charged hadron pairs with large total transverse momentum and small relative momentum, produced in proton-proton collisions with one transversely polarized proton. One of these correlations directly probes the chiral-odd transversity parton distribution in connection with a chiral-odd interference fragmentation function. We present predictions for this observable based on previous extractions of transversity (from charged pion pair production in semi-inclusive deep-inelastic scattering) and of the interference fragmentation function (from the production of back-to-back charged pion pairs in electron-positron annihilations). All analyses are performed in the framework of collinear factorization. We compare our predictions to the recent data on proton-proton collisions released by the STAR collaboration at RHIC, and we find them reasonably compatible. This comparison confirms for the first time the predicted role of transversity in proton-proton collisions and it allows to test its universality.
Comments:
5 pages, revtex4-1 with pdflatex, 4 figures in pdf format
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1604.06585 [pdf]
PRD(2016)·41 citations
09
[Submitted on 22 Apr 2016] (cross-list from hep-ph)
The decays $Λ_{b, c} \to N^{*} l ν$ in QCD
Maximilian Emmerich🇩🇪 · Nils Offen🇩🇪 · Andreas Schäfer🇩🇪
We present an exploratory study of the $Λ_{c, b} \to N^{*}$ -form factors and the semileptonic decay width within the framework of light-cone sum rules. We use two different methods and two different interpolating currents for the $Λ_{c, b}$ . As interpolating currents we choose an axial-vector like and a pseudoscalar like current. Our results show that the procedure of eliminating negative parity partners is not well suited for the case at hand and that the second approach using structures with highest powers of $p_{+}$ with an axial-vector like interpolating current gives the most reliable results. Our predictions are based on the models obtained in \cite{Anikin:2015ita,Braun:2014wpa}. The largest uncertainty comes from the uncertainty of the twist 4 parameters $η_{10}, η_{11}$ and we take the spread between the two models in \cite{Anikin:2015ita} as a measure for this. We get \begin{eqnarray} \Gamma(\Lambda_b\to N^*(1535) l \nu)&=&\left(0.0058^{+0.0010}_{-0.0009}\right)\cdot\left(\dfrac{V_{ub}}{3.5\cdot10^{-3}}\right)^2,\quad\mbox{LCSR(1)} \nonumber \Gamma(\Lambda_b\to N^*(1535) l \nu)&=&\left(0.00070^{+0.00012}_{-0.00011}\right)\cdot\left(\dfrac{V_{ub}}{3.5\cdot10^{-3}}\right)^2,\quad\mbox{LCSR(2)} \nonumber \Gamma(\Lambda_c\to N^*(1535) l \nu)&=&\left(0.0064^{+0.0012}_{-0.0011}\right)\cdot \left(\dfrac{V_{cd}}{0.225}\right)^2,\quad\mbox{LCSR(1)}\nonumber \Gamma(\Lambda_c\to N^*(1535) l \nu)&=&\left(0.00077^{+0.00016}_{-0.00014}\right)\cdot \left(\dfrac{V_{cd}}{0.225}\right)^2,\quad\mbox{LCSR(2)}\nonumber \end{eqnarray} as predictions for the respective decay widths, where LCSR(1) and LCSR(2) refer to the two different models of the distribution amplitudes of the $N^{*}$ . It is seen that even a rough measurement of these decays will greatly help to discriminate different models.
Comments:
15 pages, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1604.06595 [pdf]
J.Phys.G(2016)·8 citations
10
[Submitted on 22 Apr 2016] (cross-list from hep-ph)
Could the static properties of nuclei be deduced from the dynamics of a single quark?
B P Kosyakov🇷🇺 · E Yu Popov🇷🇺 · M A Vronskii🇷🇺
We show that the static properties of a nucleus could arise from a single quark moving in a mean field generated by all other constituents of this nucleus. The resulting model provides a way for determining the nuclear sizes characteristic of the liquid drop model, and reasonably accurate values of magnetic moments of different nuclei with the aid of two parameters $α_{s}$ and $σ$ appearing in the Cornell potential intended for use in quarkonium physics.
Comments:
13 pages, 5 figures; v2: published version, the title is somewhat changed, several conceptual clarifications are added
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1604.06613 [pdf]
EPJA(2017)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE