Nuclear Theory·nucl-th

Wednesday·July 13, 2016

7 papers—3 primary·4 cross-listed

01
[Submitted on 12 Jul 2016]
A nucleus-dependent valence-space approach to nuclear structure
S. R. Stroberg🇨🇦 · A. Calci🇨🇦 · H. Hergert🇺🇸 · J. D. Holt🇨🇦 · S. K. Bogner🇺🇸 · R. Roth🇩🇪 · A. Schwenk🇩🇪
We present a nucleus-dependent valence-space approach for calculating ground and excited states of nuclei, which generalizes the shell-model in-medium similarity renormalization group to an ensemble reference with fractionally filled orbitals. Because the ensemble is used only as a reference, and not to represent physical states, no symmetry restoration is required. This allows us to capture 3N forces among valence nucleons with a valence-space Hamiltonian specifically targeted to each nucleus of interest. Predicted ground-state energies from carbon through nickel agree with results of other large-space ab initio methods, generally to the 1\% level. In addition, we show that this new approach is required in order to obtain convergence for nuclei in the upper $p$ and $s d$ shells. Finally, we address the $1^{+}$ / $3^{+}$ ground-state inversion problem in $^{22} Na$ and $^{46} V$ . This approach extends the reach of ab initio nuclear structure calculations to essentially all light- and medium-mass nuclei.
Comments:
6 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1607.03229 [pdf]
PRL(2017)·308 citations
02
[Submitted on 12 Jul 2016]
Compact Star Matter: EoS with New Scaling Law
Kyungmin Kim🇰🇷 · Hyun Kyu Lee🇰🇷 · Jaehyun Lee🇰🇷
In this paper we present a simple discussion on the properties of compact stars using an EoS obtained in effective field theory anchored on scale and hidden-local symmetric Lagrangian endowed with topology change and a unequivocal prediction on the deformation of the compact star, that could be measured in gravitational waves. The objective is not to offer a superior or improved EoS for compact stars but to confront with a forthcoming astrophysical observable the given model formulated in what is considered to be consistent with the premise of QCD. The model so obtained is found to satisfactorily describe the observation of a 2-solar mass neutron star with a minimum number of parameters. Specifically the observable we are considering in this paper is the tidal deformability parameter (equivalently the Love number k_2), which affects gravitational wave forms at the late period of inspiral stage. The forthcoming aLIGO and aVirgo observations of gravitational waves from binary neutron star system will provide a valuable guidance for arriving at a better understanding of highly compressed baryonic matter.
Comments:
14 pages, 4 figures, to appaer in G.E. Brown Memorial Volume. arXiv admin note: substantial text overlap with arXiv:1412.5380
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1607.03235 [pdf]
IJMPE(2017)·9 citations
03
[Submitted on 12 Jul 2016]
Volume and surface contributions to the nuclear symmetry energy within the coherent density fluctuation model
A. N. Antonov · M. K. Gaidarov · P. Sarriguren · E. Moya de Guerra
The volume and surface components of the nuclear symmetry energy (NSE) and their ratio are calculated within the coherent density fluctuation model (CDFM). The estimations use the results of the model for the NSE in finite nuclei based on the Brueckner energy-density functional for nuclear matter. In addition, we present results for the NSE and its volume and surface contributions obtained by using the Skyrme energy-density functional. The CDFM weight function is obtained using the proton and neutron densities from the self-consistent HF+BCS method with Skyrme interactions. We present and discuss the values of the volume and surface contributions to the NSE and their ratio obtained for the Ni, Sn, and Pb isotopic chains studying their isotopic sensitivity. The results are compared with estimations of other approaches which have used available experimental data on binding energies, neutron-skin thicknesses, excitation energies to isobaric analog states (IAS) and also with results of other theoretical methods.
Comments:
13 pages, 12 figures, 3 tables, accepted for publication in Physical Review C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1607.03325 [pdf]
PRC(2016)·30 citations
04
[Submitted on 8 Jul 2016] (cross-list from hep-ph)
Momentum broadening in unstable quark-gluon plasma
M.E. Carrington🇨🇦 · St. Mrówczyński🇵🇱 · B. Schenke🇺🇸
Quark-gluon plasma produced at the early stage of ultrarelativistic heavy ion collisions is unstable, if weakly coupled, due to the anisotropy of its momentum distribution. Chromomagnetic fields are spontaneously generated and can reach magnitudes much exceeding typical values of the fields in equilibrated plasma. We consider a high energy test parton traversing an unstable plasma that is populated with strong fields. We study the momentum broadening parameter $q^$ which determines the radiative energy loss of the test parton. We develop a formalism which gives $q^$ as the solution of an initial value problem, and we focus on extremely oblate plasmas which are physically relevant for relativistic heavy ion collisions. The parameter $q^$ is found to be strongly dependent on time. For short times it is of the order of the equilibrium value, but at later times $q^$ grows exponentially due to the interaction of the test parton with unstable modes and becomes much bigger than the value in equilibrium. The momentum broadening is also strongly directionally dependent and is largest when the test parton velocity is transverse to the beam axis. Consequences of our findings for the phenomenology of jet quenching in relativistic heavy ion collisions are briefly discussed.
Comments:
43 pages, 5 figures, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1607.02359 [pdf]
PRC(2017)·31 citations
05
[Submitted on 12 Jul 2016] (cross-list from hep-ph)
Saturation scale fluctuations and multi-particle rapidity correlations
Adam Bzdak🇵🇱 · Kevin Dusling🇺🇸
We study the effect of intrinsic fluctuations of the proton saturation momentum scale on event-by-event rapidity distributions. Saturation scale fluctuations generate an asymmetry in the single particle rapidity distribution in each event resulting in genuine n-particle correlations having a component linear in the rapidities of the produced particles, $y_{1} \dots y_{n}$ . We introduce a color domain model that naturally explains the centrality dependence of the two-particle rapidity correlations recently measured by ATLAS while constraining the probability distribution of saturation scale fluctuations in the proton. Predictions for n = 4, 6 and 8 particle correlations find that the four and eight-particle cumulant change sign at an intermediate multiplicity, a signature which could be tested experimentally.
Comments:
12 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1607.03219 [pdf]
PRC(2016)·6 citations
06
[Submitted on 12 Jul 2016] (cross-list from hep-ph)
Understanding spin parity of $P_{c} (4450)$ and $Y (4274)$ in a hadronic molecular state picture
Jun He🇨🇳
The hidden-charmed pentaquark $P_{c} (4450)$ and the charmonium-like state $Y (4274)$ are investigated as a $D ˉ^{*} Σ_{c}$ and a $D_{s} D ˉ_{s 0} (2317)$ molecular state, respectively. The spin parities of these two states cannot be well understood if only S-wave $D ˉ^{*} Σ_{c}$ and $D_{s} D ˉ_{s 0} (2317)$ interactions are considered. In this work, the interactions are studied in a quasipotential Bethe-Salpeter equation approach with a partial wave decomposition on spin parity $J^{P}$ , and the contributions of different partial waves are studied in a two-channel scattering model including a generating channel and an observation channel. Two poles at $4447 \pm 4 i$ and $4392 \pm 46 i$ MeV are produced from the $D ˉ^{*} Σ_{c}$ interaction coupled with the $J / ψ p$ channel in $3/ 2^{-}$ wave and $5/ 2^{+}$ wave, respectively. The peak for the $5/ 2^{+}$ state has a comparable height as that of the $3/ 2^{-}$ state in the $J / ψ p$ invariant mass spectrum. The $D_{s} D ˉ_{s 0} (2317)$ interaction coupled with the $J / ψ ϕ$ channel is studied and a pole at $4275 \pm 11 i$ MeV is produced in $J^{P} = 1^{+}$ wave, which corresponds to P-wave $D_{s} D ˉ_{s 0} (2317)$ interaction. The pole from S-wave $D_{s} D ˉ_{s 0} (2317)$ interaction is far below that from P-wave interaction even the $J / ψ ϕ$ threshold, so cannot be observed in the $J / ψ ϕ$ channel. The result suggests that in these cases a state carrying a spin parity corresponding to P-wave interaction should be taken as seriously as these carrying a spin parity corresponding to S-wave interaction in the hadronic molecular state picture.
Comments:
7 pages, 5 figures. published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1607.03223 [pdf]
PRD(2017)·53 citations
07
[Submitted on 12 Jul 2016] (cross-list from hep-ph)
Dynamically Generated $Ξ (1690)$
Takayasu Sekihara (JAEA, Ibaraki)🇯🇵
We show that the $Ξ (1690)$ resonance can be dynamically generated in the $s$ -wave $K ˉ Σ$ - $K ˉ Λ$ - $π Ξ$ - $η Ξ$ coupled-channels chiral unitary approach. In our model, the $Ξ (1690)$ resonance appears near the $K ˉ Σ$ threshold as a $K ˉ Σ$ molecular state and the experimental data are reproduced well. We discuss properties of the dynamically generated $Ξ (1690)$ .
Comments:
4 pages, 4 EPS figures, talk given at the 12th International Conference on Hypernuclear and Strange Particle Physics (HYP2015), Tohoku, Japan, 7-12 Sep. 2015
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1607.03374 [pdf]
JPS Conf.Proc.(2017)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE

A nucleus-dependent valence-space approach to nuclear structure

Compact Star Matter: EoS with New Scaling Law

Volume and surface contributions to the nuclear symmetry energy within the coherent density fluctuation model

Momentum broadening in unstable quark-gluon plasma

Saturation scale fluctuations and multi-particle rapidity correlations

Understanding spin parity of Pc​(4450) and Y(4274) in a hadronic molecular state picture

Dynamically Generated Ξ(1690)

Affiliations

Understanding spin parity of $P_{c} (4450)$ and $Y (4274)$ in a hadronic molecular state picture

Dynamically Generated $Ξ (1690)$