Nuclear Theory·nucl-th

Wednesday·December 14, 2016

13 papers—10 primary·3 cross-listed

01
[Submitted on 12 Dec 2016]
Trends and Progress in Nuclear and Hadron Physics: a straight or winding road
James P. Vary🇺🇸 · Lekha Adhikari🇺🇸 · Guangyao Chen🇺🇸 · Meijian Li🇺🇸 · Yang Li🇺🇸 · Pieter Maris🇺🇸 · Wenyang Qian🇺🇸 · John R. Spence🇺🇸 · Shuo Tang🇺🇸 · Kirill Tuchin🇺🇸 · Xingbo Zhao🇺🇸
Quantitative calculations of the properties of hadrons and nuclei, with assessed uncertainties, have emerged as competitive with experimental measurements in a number of major cases. We may well be entering an era where theoretical predictions are critical for experimental progress. Cross-fertilization between the fields of relativistic hadronic structure and non-relativistic nuclear structure is readily apparent. Non-perturbative renormalization methods such as Similarity Renormalization Group and Okubo-Lee-Suzuki schemes as well as many-body methods such as Coupled Cluster, Configuration Interaction and Lattice Simulation methods are now employed and advancing in both major areas of physics. New algorithms to apply these approaches on supercomputers are shared among these areas of physics. The roads to success have intertwined with each community taking the lead at various times in the recent past. I briefly sketch these fascinating paths and comment on some symbiotic relationships. I also overview some recent results from the Hamiltonian Basis Light-Front Quantization approach.
Comments:
11 pages, 8 figures, LC2016 conference paper submitted to Few Body Systems
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1612.03963 [pdf]
Few Body Syst.(2017)·13 citations
02
[Submitted on 13 Dec 2016]
Scale-chiral symmetry, $ω$ meson and dense baryonic matter
Yong-Liang Ma🇨🇳 · Mannque Rho🇫🇷
It is shown that explicitly broken scale symmetry is essential for dense skyrmion matter in hidden local symmetry theory. Consistency with the vector manifestation fixed point for the hidden local symmetry of the lowest-lying vector mesons and the dilaton limit fixed point for scale symmetry in dense matter is found to require that the anomalous dimension ( $γ_{G^{2}}$ ) of the gluon field strength tensor squared ( $G^{2}$ ) that represents the quantum trace anomaly should be $0 < γ_{G^{2}} < 3$ .
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1612.04079 [pdf]
PRD(2018)·24 citations
03
[Submitted on 13 Dec 2016]
Beta-decay properties of neutron-rich rare-earth isotopes
P. Sarriguren
In this paper, beta-decay properties of even-even neutron-rich isotopes in the rare-earth mass region are studied within a microscopic theoretical approach based on a proton-neutron quasiparticle random-phase approximation. The underlying mean field is constructed selfconsistently from a deformed Hartree-Fock calculation with Skyrme interactions and pairing correlations to which particle-hole and particle-particle residual interactions are added. Nuclei in this mass region participate in the astrophysical rapid neutron capture process and are directly involved in the generation of the rare-earth peak in the isotopic abundance pattern centered at A=160. The energy distributions of the Gamow-Teller strength as well as the beta-decay half-lives and the beta-delayed neutron-emission probabilities are discussed and compared with the available experimental information and with calculations based on different approaches.
Comments:
12 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1612.04084 [pdf]
PRC(2017)·14 citations
04
[Submitted on 13 Dec 2016]
Calculations of kaonic nuclei based on chiral meson-baryon coupled channel interaction models
J. Hrtánková🇨🇿 · A. Cieplý🇨🇿 · J. Mareš🇨🇿
We present our latest calculations of $K^{-}$ -nuclear quasi-bound states using a self-consistent scheme for constructing $K^{-}$ -nuclear potentials from various subthreshold chirally inspired $K ˉ N$ scattering amplitudes. We consider in-medium versions of the scattering amplitudes taking into account Pauli blocking in the intermediate states. The resulting $K^{-}$ binding energies as well as the widths exhibit the same A dependence, however, the binding energies strongly depend on the model used.
Comments:
4 pages, proceedings of the MESON 2016 conference, Krakow, Poland, June 2 - 7, 2016
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1612.04087 [pdf]
EPJ Web Conf.(2016)·0 citations
05
[Submitted on 13 Dec 2016]
An estimate of Alpha decay half-life from the poles of S-matrix of an exactly solvable potential
Swagatika Bhoi · Basudeb Sahu
We develop a versatile and analytically solvable potential which fairly reproduces the combined potential of an $α +$ nucleus system resulting from both the attractive nuclear and repulsive electrostatic potentials. The potential is expressed in terms of the radial position, mass and proton number of the $α$ -particle and the daughter nucleus and certain parameters governing the depth, height and steepness of the barrier. The potential generated is typically a pocket near the origin and a barrier adjacent to it. The Schrödinger equation with the above mentioned potential is then solved for the wave function. This potential produces discrete positive energy quasibound state known as resonance state. By matching the wave function and its derivative with the regular Coulomb wave function $F_{0}$ and irregular Coulomb wave function $G_{0}$ , we obtain the S-matrix analytically. The resonance is obtained from the pole in complex energy plane which gives the width of the corresponding time of decay through the imaginary part of the energy pole position. We make a comparative study of the measured half-lives of various nuclei with the calculated half-lives. The calculated values of half-lives closely match with the corresponding experimental results.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1612.04135 [pdf]
DAE Symp.Nucl.Phys.(2016)·0 citations
06
[Submitted on 13 Dec 2016]
A microscopically derived formula for alpha-decay half-lives
Swagatika Bhoi · Basudeb Sahu
Although Geiger-Nuttall (GN) law gives a single straight line, if we consider the experimental data of alpha particle emitters including heavy and super heavy nuclei with proton numbers as large as 118, instead of getting a single linear path we observe several linear segments with different slopes and intercepts. This problem is overcome when the experimental results in logarithm form are plotted as a function of Viola-Seaborg (VS) parameters with values of parameters set by hand. By using the fundamental principle of decay, we derive a formula of logarithm of half-lives in terms of well-defined parameters or coefficients and this replaces the empirical VS rule.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1612.04140 [pdf]
0 citations
07
[Submitted on 13 Dec 2016]
A multi-channel model for an {\alpha} plus $^{6}$ He nucleus cluster
K. Amos · L. Canton · P. R. Fraser · S. Karataglidis · J. P. Svenne · D. van der Knijff
A multi-channel algebraic scattering (MCAS) method has been used to solve coupled sets of Lippmann-Schwinger equations for the $α$ + $^{6}$ He cluster system, so finding a model spectrum for $^{10}$ Be to more than 10 MeV excitation. Three states of $^{6}$ He are included and the resonance character of the two excited states taken into account in finding solutions. A model Hamiltonian has been found that gives very good agreement with the known bound states and with some low-lying resonances of $^{10}$ Be. More resonance states are predicted than have as yet been observed. The method also yields $S$ -matrices which we have used to evaluate low-energy $^{6}$ He- $α$ scattering cross sections. Reasonable reproduction of low-energy differential cross sections and of energy variation of cross sections measured at fixed scattering angles is found.
Comments:
18 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1612.04192 [pdf]
EPJA(2017)·5 citations
08
[Submitted on 13 Dec 2016]
Constraining Superfluidity in Dense Matter from the Cooling of Isolated Neutron Stars
Spencer Beloin (1) · Sophia Han (1) · Andrew W. Steiner (1 and 2) · Dany Page (3) ((1) Tennessee U., (2) Oak Ridge, (3) UNAM, Inst. Astron.)
We present a quantitative analysis of superfluidity and superconductivity in dense matter from observations of isolated neutron stars in the context of the minimal cooling model. Our new approach produces the best fit neutron triplet superfluid critical temperature, the best fit proton singlet superconducting critical temperature, and their associated statistical uncertainties. We find that the neutron triplet critical temperature is likely $2.0 9_{- 1.41}^{+ 4.37} \times 1 0^{8}$ K and that the proton singlet critical temperature is $7.5 9_{- 5.81}^{+ 2.48} \times 1 0^{9}$ K. However, we also show that this result only holds if the Vela neutron star is not included in the data set. If Vela is included, the gaps increase significantly to attempt to reproduce Vela's lower temperature given its young age. Further including neutron stars believed to have carbon atmospheres increases the neutron critical temperature and decreases the proton critical temperature. Our method demonstrates that continued observations of isolated neutron stars can quantitatively constrain the nature of superfluidity in dense matter.
Comments:
13 pages, 4 figures, version to be published in Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
1612.04289 [pdf]
PRC(2018)·46 citations
09
[Submitted on 13 Dec 2016]
Symmetry-guided large-scale shell-model theory
Kristina D. Launey🇺🇸 · Tomas Dytrych🇺🇸 · Jerry P. Draayer🇺🇸
In this review, we present a symmetry-guided strategy that utilizes exact as well as partial symmetries for enabling a deeper understanding of and advancing ab initio studies for determining the microscopic structure of atomic nuclei. These symmetries expose physically relevant degrees of freedom that, for large-scale calculations with QCD-inspired interactions, allow the model space size to be reduced through a very structured selection of the basis states to physically relevant subspaces. This can guide explorations of simple patterns in nuclei and how they emerge from first principles, as well as extensions of the theory beyond current limitations toward heavier nuclei and larger model spaces. This is illustrated for the ab initio symmetry-adapted no-core shell model (SA-NCSM) and two significant underlying symmetries, the symplectic Sp(3,R) group and its deformation-related SU(3) subgroup. We review the broad scope of nuclei, where these symmetries have been found to play a key role: from light to intermediate-mass nuclei, based on first-principle explorations; through the Hoyle state in C-12, within a no-core shell-model perspective; up to strongly deformed species of the rare-earth and actinide regions, as investigated in earlier studies. A complementary picture, driven by symmetries dual to Sp(3,R), is also discussed. We briefly review symmetry-guided techniques that prove useful in various nuclear-theory models, such as Elliott model, ab initio SA-NCSM, symplectic model, pseudo-SU(3) and pseudo-symplectic models, ab initio hyperspherical harmonics method, ab initio lattice effective field theory, exact pairing-plus-shell model approaches, and cluster models. Important implications of these approaches that have deepened our understanding of emergent phenomena in nuclei, such as enhanced collectivity, giant resonances, pairing, halo, and clustering, are discussed.
Comments:
Review article; 54 pages, 22 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1612.04298 [pdf]
PPNP(2016)·128 citations
10
[Submitted on 13 Dec 2016]
Equation of state of nuclear and neutron matter at third-order in perturbation theory from chiral EFT
J. W. Holt · N. Kaiser
We compute from chiral two- and three-nucleon interactions the energy per particle of symmetric nuclear matter and pure neutron matter at third-order in perturbation theory including self-consistent second-order single-particle energies. Particular attention is paid to the third-order particle-hole ring-diagram, which is often neglected in microscopic calculations of the equation of state. We provide semi-analytic expressions for the direct terms from central and tensor model-type interactions that are useful as theoretical benchmarks. We investigate uncertainties arising from the order-by-order convergence in both many-body perturbation theory and the chiral expansion. Including also variations in the resolution scale at which nuclear forces are resolved, we provide new error bands on the equation of state, the isospin-asymmetry energy, and its slope parameter. We find in particular that the inclusion of third-order diagrams reduces the theoretical uncertainty at low densities, while in general the largest error arises from omitted higher-order terms in the chiral expansion of the nuclear forces.
Comments:
10 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1612.04309 [pdf]
PRC(2017)·131 citations

Affiliations

first authorsco-authorsvia INSPIRE