Nuclear Theory·nucl-th

Wednesday·December 5, 2018

8 papers—5 primary·3 cross-listed

01
[Submitted on 4 Dec 2018]
Shape evolution of Zr nuclei and roles of tensor force
S. Miyahara · H. Nakada
Shape evolution of Zr nuclei are investigated by the axial Hartree-Fock (HF) calculations using the semi-realistic interaction M3Y-P6, with focusing on roles of the tensor force. Deformation at $N \approx 40$ is reproduced, which has not been easy to describe within the self-consistent mean-field calculations. The spherical shape is obtained in $46 \leq N \leq 56$ , and the prolate deformation is predicted in $58 \leq N \leq 72$ , while the shape switches to oblate at $N = 74$ . The sphericity returns at $N = 80$ and $82$ . The deformation in $60 ≲ N ≲ 70$ resolves the discrepancy in the previous magic-number prediction based on the spherical mean-field calculations [Prog. Theor. Exp. Phys. \textbf{2014}, 033D02]. It is found that the deformation at $N \approx 40$ takes place owing to the tensor force with a good balance. The tensor-force effects significantly depend on the configurations, and are pointed out to be conspicuous when the unique-parity orbit (e.g. $n 0 h_{11/2}$ ) is present near the Fermi energy, delaying deformation. These effects are crucial for the magicity at $N = 56$ and for the predicted shape change at $N = 74$ and $80$ .
Comments:
10 pages, 15 figures; to be published in PRC
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1812.01169 [pdf]
PRC(2018)·24 citations
02
[Submitted on 4 Dec 2018]
Heavy quarkonium dissociation in the finite space of heavy-ion collisions
Jihong Guo · Wu-Sheng Dai · Mi Xie · Yunpeng Liu
The dissociation of heavy quarkonia in the constrained space is calculated at leading order compared with that in infinitely large medium. To deal with the summation of the discrete spectrum, a modified Euler-Maclaurin formula is developed as our numerical algorithm. We find that with the constraint in space, the dissociation of quarkonia at early time becomes negligible.
Comments:
10 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1812.01211 [pdf]
PRC(2019)·3 citations
03
[Submitted on 4 Dec 2018]
Ab initio folding potentials for proton-nucleus scattering with NCSM nonlocal one-body densities
Ch. Elster · M. Burrows · S.P. Weppner · K. Launey · P. Maris · G. Popa
Based on the spectator expansion of the multiple scattering series we employ a nonlocal translationally invariant nuclear density derived from a chiral next-to-next-to-leading order (NNLO) and the very same interaction for consistent full-folding calculations of the effective (optical) potential for nucleon-nucleus scattering for light nuclei.
Comments:
Proceedings FB22 caen France 2018
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1812.01443 [pdf]
Springer Proc.Phys.(2020)·0 citations
04
[Submitted on 4 Dec 2018]
Dipole-dipole interactions between neutrons
Renato Higa🇧🇷 · James F. Babb🇺🇸 · Mahir S. Hussein🇧🇷
In this work we present results of the dipole-dipole interactions between two neutrons, a neutron and a conducting wall, and a neutron between two walls. As input, we use dynamical electromagnetic dipole polarizabilities fitted to chiral EFT results up to the pion production threshold and at the onset of the Delta resonance. Our work can be relevant to the physics of confined ultracold neutrons inside bottles.
Comments:
4 pages, 8 figures, contribution to the proceedings of the XXII International Conference on Few-Body Problems in Physics
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1812.01462 [pdf]
Springer Proc.Phys.(2020)·1 citation
05
[Submitted on 4 Dec 2018]
Muon-electron lepton-flavor violating transitions: shell-model calculations of transitions in 27Al
J.Kostensalo🇫🇮 · J. Suhonen🇫🇮 · O. Civitarese🇦🇷
In this paper we present the results of large-scale shell-model calculations of muon-to-electron lepton-flavor violating transitions for the case of the target nucleus 27Al. We extend the previous shell-model calculations, done in the sd model space, by including also the p orbitals in order to see whether the negative-parity states produce any significant effect in the conversion rate. The analysis of the results shows the dominance of coherent transitions mediated by isovector operators and going by the ground state of the target, with practically null influence of excited positive- or negative-parity states.
Comments:
6 pages, 1 figure, 20 references
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1812.01493 [pdf]
PRC(2018)·2 citations
06
[Submitted on 3 Dec 2018] (cross-list from hep-lat)
Towards the P-wave nucleon-pion scattering amplitude in the $Δ (1232)$ channel
Srijit Paul🇨🇾 · Giorgio Silvi🇩🇪 · Constantia Alexandrou🇨🇾 · Giannis Koutsou🇨🇾 · Stefan Krieg🇩🇪 · Luka Leskovec🇺🇸 · Stefan Meinel🇺🇸 · John Negele🇺🇸 · Marcus Petschlies🇩🇪 · Andrew Pochinsky🇺🇸 · Gumaro Rendon🇺🇸 · Sergey Syritsyn🇺🇸
We use lattice QCD and the Lüscher method to study elastic pion-nucleon scattering in the isospin $I = 3/2$ channel, which couples to the $Δ (1232)$ resonance. Our $N_{f} = 2 + 1$ flavor lattice setup features a pion mass of $m_{π} \approx 250$ MeV, such that the strong decay channel $Δ \to π N$ is close to the threshold. We present our method for constructing the required lattice correlation functions from single- and two-hadron interpolating fields and their projection to irreducible representations of the relevant symmetry group of the lattice. We show preliminary results for the energy spectra in selected moving frames and irreducible representations, and extract the scattering phase shifts. Using a Breit-Wigner fit, we also determine the resonance mass $m_{Δ}$ and the $g_{Δ - π N}$ coupling.
Comments:
14 pages, 7 figures, Proceedings of the 36th Annual International Symposium on Lattice Field Theory (Lattice 2018), 22-28 July 2018, Michigan State University, East Lansing, Michigan USA
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1812.01059 [pdf]
PoS(2018)·12 citations
07
[Submitted on 3 Dec 2018] (cross-list from quant-ph)
Nuclear decay parameter oscillations as possible signal of quantum-mechanical nonlinearity and emergent gravity
S.N. Mayburov🇷🇺
Several experimental groups reported the evidence of multiple periodic modulations of nuclear decay constants which amplitudes are of the order .1% and periods of one year, 24 hours or about one month. We argue that such deviations from radioactive decay law can be described in nonlinear quantum mechanics framework, in which decay process obeys to nonlinear Shroedinger equation with Doebner-Goldin terms. Proposed corrections to Hamiltonian of quantum system interaction with gravitation field correspond to some emergent gravity theories, in particular, bilocal gravity model. Decay parameter variations under influence of Sun gravity, calculated in our model, agree well with experimental results for alpha-decay life-time oscillations of Polonium isotopes
Comments:
10 pages, talk given at 'Quantum Structures - 2018' conference, Kazan, Russia, July 2018, Int. J. Theor. Phys. (2021) DOI 10.1007/s10773-019-04237x
Subjects:
Quantum Physics (quant-ph); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1812.01455 [pdf]
Int.J.Theor.Phys.(2021)·3 citations
08
[Submitted on 4 Dec 2018] (cross-list from hep-ph)
Polynomiality sum rules for generalized parton distributions of spin-1 targets
W. Cosyn🇧🇪 · A. Freese🇺🇸 · B. Pire🇫🇷
We present the polynomiality sum rules for all leading-twist quark and gluon generalized parton distributions (GPDs) of spin-1 targets such as the deuteron nucleus. The sum rules connect the Mellin moments of these GPDs to polynomials in skewness parameter $ξ$ , which contain generalized form factors (GFFs) as their coefficients. The decompositions of local currents in terms of generalized form factors for spin-1 targets are obtained as a byproduct of this derivation.
Comments:
21 pages, minor revisions, published in PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1812.01511 [pdf]
PRD(2019)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE