Nuclear Theory·nucl-th

Monday·September 2, 2019

9 papers—3 primary·6 cross-listed

01
[Submitted on 29 Aug 2019]
$Ω$ -deuteron Interaction in Folding Model
Faisal Etminan🇮🇷 · Mohammad Mehdi Firoozabadi🇮🇷
A simple single folding model for $Ω$ -deuteron with maximal spin $(I) J^{P} = (0) 5/ 2^{+}$ is investigated. $Ω$ is assumed to orbit an unperturbed deuteron in a $Ω$ -deuteron potential based on a separable $Ω$ -nucleon potential from lattice QCD. We show that the effective central folding potential of $Ω d$ in the $^{5} S_{2}$ channel has a simple Wood-Saxon form, and approximate the upper bound for the binding energy of $Ω$ particle on a deuteron. In order to investigate how changes in the wave functions affect the results, we consider four analytical forms for $S$ -state deuteron wave functions, i.e., two widely used Hulthén forms, as well as the modified Reid93 and Argonne v18 forms. Our calculations of binding energy from simple two-body approximation are compared with the results reported for the three-body problem; it is confirmed that the $Ω d$ system is deeply bound. Although the single folding model reduces the three-body problem to a two-body problem, this simplification is inadequate.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1908.11484 [pdf]
7 citations
02
[Submitted on 30 Aug 2019]
$^{12} C +^{16} O$ molecular resonances at deep sub-barrier energy
Yasutaka Taniguchi · Masaaki Kimura
The existence of $^{12} C +^{16} O$ molecular resonances at sub-barrier energy has been a significant problem in nuclear astrophysics because they strongly affect the $^{12} C +^{16} O$ fusion reaction rate in type Ia supernovae and heavy stars. However, experimental surveys have been limited to 4~MeV and cannot access the deep sub-barrier energy due to a very small fusion cross section. Here we predict a couple of resonances with $J^{π} = 0^{+}$ , $2^{+}$ , and $4^{+}$ in the deep sub-barrier energy based on the antisymmetrized molecular dynamics calculation that reproduces the known resonances and low-lying spectrum of $^{28} Si$ .
Comments:
10 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex)
arXiv:
1908.11638 [pdf]
PLB(2020)·11 citations
03
[Submitted on 30 Aug 2019]
Constraints on Skyrme Equations of State from Doubly Magic Nuclei, Ab-Initio Calculations of Low-Density Neutron Matter, and Neutron Stars
C. Y. Tsang · B. A. Brown · F.J. Fattoyev · W. G. Lynch · M. B. Tsang
We use properties of doubly-magic nuclei, ab-initio calculations of low-density neutron matter, and of neutron stars to constrain the parameters of the Skyrme energy-density functional. We find all of these properties can be reproduced within a constrained family of Skyrme parameters. The maximum mass of a neutron star is found to be sensitive to the neutron effective mass. A value of [ $m_{n}^{*} / m] (ρ_{0}) = 0.60 - 0.65$ is required to obtain a maximum neutron star mass of 2.1 solar masses. Using the constrained Skyrme functional with the aforementioned effective mass, the predicted radius for a neutron star of 1.4 solar masses is 12.4(1) km and $Λ$ = 423(40).
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1908.11842 [pdf]
PRC(2019)·16 citations
04
[Submitted on 30 Aug 2019] (cross-list from hep-ph)
Review of predictions of hard probes in $p +$ Pb collisions at $s_{N N} = 5.02$ and 8.16 TeV and comparison with data
R. Vogt🇺🇸
Predictions have been compiled for the $p +$ Pb LHC runs, focusing on production of hard probes in cold nuclear matter. These predictions were first made for the $s_{_{N N}} = 5.02$ TeV $p +$ Pb run and were later compared to the available data. A similar set of predictions were published for the 8.16~TeV $p +$ Pb run. A selection of the predictions are reviewed here.
Comments:
6 pages, 3 figures, Presented at EDS Blois 2019 Conference, Quy Nhon, Vietnam, June 23--28, 2019
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1908.11534 [pdf]
1 citation
05
[Submitted on 30 Aug 2019] (cross-list from astro-ph.HE)
Photon vortex generation in quantum level by high-order harmonic synchrotron radiations from spiral moving electrons in magnetic fields
Tomoyuki Maruyama🇯🇵 · Takehito Hayakawa🇯🇵 · Toshitaka Kajino🇯🇵 · Myung-Ki Cheoun🇰🇷
We explore photon vortex generation in synchrotron radiations from a spiral moving electron under a uniform magnetic field along z-axis using Landau quantization. The obtained wave-function of the photon vortecies is the eigen-state of the z-component of the total angular momentum (zTAM). In m-th harmonic radiations, individual photons are the eigen-state of zTAM of m. This is consistent with previous studies. Using the presently obtained wave-functions we calculate the decay widths and the energy spectra under extremely strong magnetic fields of 10^12 - 10^13 G, which are observed in astrophysical objects such as magnetized neutron stars and jets and accretion disks around black holes. The result suggests that photon vortices are predominantly generated in such objects. Although they have no coherency it is expected that photon vortices from the universe are measured using a detector based upon a quantum effect in future. This effect also affects to stellar nucleosynthesis in strong magnetic fields.
Comments:
12 pages, 4 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th); physics.optics (physics.optics); Quantum Physics (quant-ph)
arXiv:
1908.11545 [pdf]
0 citations
06
[Submitted on 30 Aug 2019] (cross-list from hep-ph)
Theoretical interpretation of the $D_{s}^{+} \to π^{+} π^{0} η$ decay and the nature of $a_{0} (980)$
Raquel Molina🇨🇳 · Ju-Jun Xie🇨🇳 · Wei-Hong Liang🇨🇳 · Li-Sheng Geng🇨🇳 · Eulogio Oset🇨🇳
In a recent paper \cite{Ablikim:2019pit}, the BESIII collaboration reported the so-called first observation of pure $W$ -annihilation decays $D_{s}^{+} \to a_{0}^{+} (980) π^{0}$ and $D_{s}^{+} \to a_{0}^{0} (980) π^{+}$ . The measured absolute branching fractions are, however, puzzlingly larger than those of other measured pure $W$ -annihilation decays by at least one order of magnitude. In addition, the relative phase between the two decay modes is found to be about 180 degrees. In this letter, we show that all these can be easily understood if the $a_{0} (980)$ is a dynamically generated state from $K ˉ K$ and $π η$ interactions in coupled channels. In such a scenario, the $D_{s}^{+}$ decay proceeds via internal $W$ emission instead of $W$ -annihilation, which has a larger decay rate than $W$ -annihilation. The proposed decay mechanism and the molecular nature of the $a_{0} (980)$ also provide a natural explanation to the measured negative interference between the two decay modes.
Comments:
Version for publication
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1908.11557 [pdf]
PLB(2020)·48 citations
07
[Submitted on 30 Aug 2019] (cross-list from hep-ph)
Kinetic freeze-out temperature from yields of short-lived resonances
Anton Motornenko🇩🇪 · Volodymyr Vovchenko🇩🇪 · Carsten Greiner🇩🇪 · Horst Stoecker🇩🇪
A method to determine the kinetic freeze-out temperature in heavy-ion collisions from measured yields of short-lived resonances is presented. The resonance production is treated in the framework of thermal model with an evolution between chemical and kinetic freeze-outs. The yields of many short-lived resonances are suppressed at $T = T_{kin} < T_{ch}$ . We determine the values of $T_{kin}$ and $T_{ch}$ for various centralities in Pb--Pb collisions at $s_{_{N N}} = 2.76$ TeV by fitting the abundances of both the stable hadrons and the short-lived resonances such as $ρ^{0}$ and $K^{* 0}$ , that were measured by the ALICE collaboration. This allows to extract the kinetic freeze-out temperature from the measured hadron and resonance yields alone, independent of assumptions about the flow velocity profile and the freeze-out hypersurface. The extracted $T_{ch}$ values exhibit a moderate multiplicity dependence whereas $T_{kin}$ drops, from $T_{kin} ≃ T_{ch} ≃ 155$ MeV in peripheral collisions to $T_{kin} ≃ 110$ MeV in 0-20% central collisions. Predictions for other short-lived resonances are presented. A potential (non-)observation of a suppressed $f_{0} (980)$ meson yield will allow to constrain the lifetime of that meson.
Comments:
6 pages, 3 figures. Version published in Physical Review C
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1908.11730 [pdf]
PRC(2020)·51 citations
08
[Submitted on 29 Aug 2019] (cross-list from hep-ph)
Unequal rapidity correlators in the dilute limit of JIMWLK
Tuomas Lappi🇫🇮 · Andrecia Ramnath🇫🇮
We study unequal rapidity correlators in the stochastic Langevin picture of Jalilian-Marian - Iancu - McLerran - Weigert - Leonidov - Kovner (JIMWLK) evolution in the Color Glass Condensate effective field theory. By separately evolving the Wilson lines in the direct and complex conjugate amplitudes, we use the formalism to study two-particle production at large rapidity separations. We show that the evolution between the rapidities of the two produced particles can be expressed as a linear equation, even in the full nonlinear limit. We also show how the Langevin formalism for two-particle correlations reduces to a BFKL picture in the dilute limit and in momentum space, providing an interpretation of BFKL evolution as a stochastic process for color charges.
Comments:
5 pages, Talk by A.R. at DIS2019
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1908.11748 [pdf]
PoS(2019)·1 citation
09
[Submitted on 30 Aug 2019] (cross-list from hep-ph)
Dynamical generation of resonances in the P33 partial wave
B. Golli🇸🇮 · H. Osmanović🇧🇦 · S. Širca🇸🇮
We investigate the formation of resonances in the P33 partial wave with the emphasis on possible emergence of dynamically generated quasi-bound states as a consequence of a strong $p$ -wave pion attractive interaction in this partial wave, as well as their possible interaction with the genuine quark excited states. By using the Laurent-Pietarinen expansion we follow the evolution of the $S$ -matrix poles in the complex energy plane as a function of the interaction strength. Already without introducing a genuine quark resonant state, two physically interesting resonances emerge with pole masses around 1200 MeV and 1400 MeV, with the dominant $π N$ and $π Δ$ component, respectively. The added genuine resonant state in the $(1 s)^{3}$ quark configuration mixes with the lower dynamically generated resonance forming the physical $Δ (1232)$ resonance, and pushes the second dynamical resonance to around 1500 MeV, which allows it to be identified with the $Δ (1600)$ resonance. Adding a second resonant state with one quark promoted to the $2 s$ orbit generates another pole whose evolution remains well separated from the lower two poles. We calculate the helicity amplitudes at the pole and suggest that their $Q^{2}$ dependence could be a decisive test to discriminate between different models of the $Δ (1600)$ resonance.
Comments:
10 pages, 10 figures, to be published in Phys. Rev. C
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1908.11750 [pdf]
PRC(2019)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE