Nuclear Theory·nucl-th

Thursday·December 10, 2015

11 papers—7 primary·4 cross-listed

01
[Submitted on 8 Dec 2015]
Effects of pairing correlation on low-lying quasi-particle resonance in neutron drip-line nuclei
Yoshihiko Kobayashi · Masayuki Matsuo
We discuss effects of pairing correlation on quasi-particle resonance. We analyze in detail how the width of low-lying quasi-particle resonance is governed by the pairing correlation in the neutron drip-line nuclei. We consider the 46Si + n system to discuss low-lying p wave quasi-particle resonance. Solving the Hartree-Fock-Bogoliubov equation in the coordinate space with scattering boundary condition, we calculate the phase shift, the elastic cross section, the resonance width and the resonance energy. We found that the pairing correlation has an effect to reduce the width of quasi-particle resonance which originates from a particle-like orbit in weakly bound nuclei.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1512.02675 [pdf]
PTEP(2016)·14 citations
02
[Submitted on 9 Dec 2015]
Composite nature of Lambda(1405) from the spacial structure of KbarN system
Kenta Miyahara🇯🇵 · Tetsuo Hyodo🇯🇵
We discuss the spacial structure of the resonance state, Lambda(1405), solving the Schrodinger equation with the KbarN local potential. The potential is constructed by paying attention to the two points, the constraint from the recent experimental data and the reliability in the complex energy region. Using the new local potential, we investigate the KbarN spacial structure and obtain the result indicating that Lambda(1405) is the meson-baryon molecular state, that is, the composite state.
Comments:
2 pages, 1 figure
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1512.02735 [pdf]
JPS Conf.Proc.(2017)·4 citations
03
[Submitted on 9 Dec 2015]
Role of nucleonic Fermi surface depletion in neutron star cooling
J. M. Dong🇨🇳 · U. Lombardo🇮🇹 · H. F. Zhang🇨🇳 · W. Zuo🇨🇳
The Fermi surface depletion of beta-stable nuclear matter is calculated to study its effects on several physical properties which determine the neutron star thermal evolution. The neutron and proton Z factors measuring the corresponding Fermi surface depletions, are calculated within the Brueckner-Hartree-Fock approach employing the AV18 two-body force supplemented by a microscopic three body force. Neutrino emissivity, heat capacity and, in particular, neutron 3PF2 superfluidity turn out to be reduced, especially at high baryonic density, to such an extent that the cooling rates of young neutron stars are significantly slowed
Comments:
9 pages, 6 figures, accepted for publication in ApJ
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1512.02746 [pdf]
ApJ(2016)·30 citations
04
[Submitted on 9 Dec 2015]
Penta-quark States with Strangeness, Hidden Charm and Beauty
Jia-Jun Wu🇦🇺 · B. S. Zou🇨🇳
The classical quenched quark models with three constituent quarks provide a good description for the baryon spatial ground states, but fail to reproduce the spectrum of baryon excited states. More and more evidences suggest that unquenched effects with multi-quark dynamics are necessary ingredients to solve the problem. Several new hyperon resonances reported recently could fit in the picture of penta-quark states. Based on this picture, some new hyperon excited states were predicted to exist; meanwhile with extension from strangeness to charm and beauty, super-heavy narrow $N^{*}$ and $Λ^{*}$ resonances with hidden charm or beauty were predicted to be around 4.3 and 11 GeV, respectively. Recently, two of such $N^{*}$ with hidden charm might have been observed by the LHCb experiment. More of those states are expected to be observed in near future. This opens a new window in order to study hadronic dynamics for the multi-quark states.
Comments:
Talk given at the 10th International Workshop on the Physics of Excited Nucleons (NSTAR2015), Osaka, May 25--28 2015
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1512.02770 [pdf]
JPS Conf.Proc.(2016)·4 citations
05
[Submitted on 9 Dec 2015]
What are the early degrees of freedom in ultra-relativistic nucleus-nucleus collisions?
Pierre Moreau🇩🇪 · Olena Linnyk🇩🇪 · Wolfgang Cassing🇩🇪 · Elena Bratkovskaya🇩🇪
The Parton-Hadron-String-Dynamics (PHSD) transport model is used to study the impact on the choice of initial degrees of freedom on the final hadronic and electromagnetic observables in Au+Au collisions at $s_{N N}$ = 200 GeV. We find that a non-perturbative system of massive gluons (scenario I) and a system dominated by quarks and antiquarks (scenario II) lead to different hadronic observables when imposing the same initial energy-momentum tensor $T_{μν} (x)$ just after the passage of the impinging nuclei. In case of the gluonic initial condition the formation of $s, s ˉ$ pairs in the QGP proceeds rather slow such that the anti-strange quarks and accordingly the $K^{+}$ mesons do not achieve chemical equilibrium even in central Au+Au collisions at $s_{N N}$ = 200 GeV. Accordingly, the $K^{+}$ rapidity distribution is suppressed in the gluonic scenario and in conflict with the data from the BRAHMS Collaboration. The proton and antiproton rapidity distributions also disfavor the scenario I. Furthermore, a clear suppression of direct photon and dilepton production is found for the pure gluonic initial conditions which is not so clearly seen in the present photon and dilepton spectra from Au+Au collisions at $s_{N N}$ = 200 GeV due to a large contribution from other channels. It is argued that dilepton spectra in the invariant mass range 1.2 GeV $< M <$ 3 GeV will provide a definitive answer once the background from correlated $D$ -meson decays is subtracted experimentally.
Comments:
9 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1512.02875 [pdf]
PRC(2016)·8 citations
06
[Submitted on 9 Dec 2015]
Symmetry broken and restored coupled-cluster theory. II. Global gauge symmetry and particle number
T. Duguet🇫🇷 · A. Signoracci🇺🇸
We have recently extended many-body perturbation theory and coupled-cluster theory performed on top of a Slater determinant breaking rotational symmetry to allow for the restoration of the angular momentum at any truncation order [T. Duguet, J. Phys. G: Nucl. Part. Phys. 42 (2015) 025107]. Following a similar route, we presently extend Bogoliubov many-body perturbation theory and Bogoliubov coupled cluster theory performed on top of a Bogoliubov reference state breaking global gauge symmetry to allow for the restoration of the particle number at any truncation order. Eventually, formalisms can be merged to handle $S U (2)$ and $U (1)$ symmetries at the same time. Several further extensions of the newly proposed many-body formalisms can be foreseen in the mid-term future. The long-term goal relates to the ab initio description of near-degenerate finite quantum systems with an open-shell character.
Comments:
45 pages, 16 figures
Subjects:
Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
1512.02878 [pdf]
J.Phys.G(2017)·64 citations
07
[Submitted on 9 Dec 2015]
Faddeev-type calculation of (d,n) transfer reactions in three-body nuclear systems
A. Deltuva
Exact Faddeev-type three-body equations are applied to the study of the proton transfer reactions $(d, n)$ in the system consisting of a nuclear core and two nucleons. The integral equations for the three-body transition operators are solved in the momentum-space framework including the Coulomb interaction via the screening and renormalization method. For a weakly bound final nucleus the calculation of the $(d, n)$ reaction is more demanding in terms of the screening radius as compared to the $(d, p)$ reaction. Well converged differential cross section results are obtained for $^{7} B e (d, n)^{8} B$ , $^{12} C (d, n)^{13} N$ , and $^{16} O (d, n)^{17} F$ reactions. A comparison with the corresponding $(d, p)$ reactions is made. The calculations fail to reproduce the shape of the angular distribution for reactions on $^{12} C$ but provide quite successful description for reactions on $^{16} O$ , especially for the transfer to the $^{17} F$ excited state $1/ 2^{+}$ when using a nonlocal optical potential.
Comments:
7 pages, 7 figures, to be published in Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1512.02955 [pdf]
PRC(2015)·7 citations
08
[Submitted on 8 Dec 2015] (cross-list from hep-th)
Retarded Correlators in Kinetic Theory: Branch Cuts, Poles and Hydrodynamic Onset Transitions
Paul Romatschke🇺🇸
In this work the collective modes of an effective kinetic theory description based on the Boltzmann equation in relaxation time approximation applicable to gauge theories at weak but finite coupling and low frequencies are studied. Real time retarded two-point correlators of the energy-momentum tensor and the R-charge current are calculated at finite temperature in flat space-times for large N gauge theories. It is found that the real time correlators possess logarithmic branch cuts which in the limit of large coupling disappear and give rise to non-hydrodynamic poles that are reminiscent of quasi-normal modes in black holes. In addition to branch cuts, correlators can have simple hydrodynamic poles, generalizing the concept of hydrodynamic modes to intermediate wavelength. Surprisingly, the hydrodynamic poles cease to exist for some critical value of the wavelength and coupling reminiscent of the properties of onset transitions.
Comments:
13 pages, 2 figures
Subjects:
High Energy Physics — Theory (hep-th); Quantum Gases (cond-mat.quant-gas); Nuclear Theory (nucl-th)
arXiv:
1512.02641 [pdf]
EPJC(2016)·112 citations
09
[Submitted on 9 Dec 2015] (cross-list from hep-lat)
Finite-volume Hamiltonian method for $π π$ scattering in lattice QCD
Jia-Jun Wu🇦🇺 · T.-S. Harry Lee🇺🇸 · Derek B. Leinweber🇦🇺 · A. W. Thomas🇦🇺 · Ross D. Young🇦🇺
Within a formulation of $π π$ scattering, we investigate the use of the finite-volume Hamiltonian approach to resolving scattering observables from lattice QCD spectra. We consider spectra in the centre-of-mass and moving frames for both S- and P-wave cases. Furthermore, we investigate the multi-channel case. Here we study the use of the Hamiltonian framework as a parametrization that can be fit directly to lattice spectra. Through this method, the hadron properties, such as mass, width and coupling, can be directly extracted from the lattice spectra.
Comments:
Talk given at the 10th International Workshop on the Physics of Excited Nucleons (NSTAR2015), Osaka, May 25--28 2015
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1512.02771 [pdf]
JPS Conf.Proc.(2016)·5 citations
10
[Submitted on 9 Dec 2015] (cross-list from hep-ph)
Standard model contribution to the electric dipole moment of the deuteron, $^{3}$ H, and $^{3}$ He nuclei
Nodoka Yamanaka🇯🇵 · Emiko Hiyama🇯🇵
We calculate for the first time the electric dipole moment (EDM) of the deuteron, $^{3}$ H, and $^{3}$ He nuclei generated by the one-meson exchange CP-odd nuclear force in the standard model. The effective $∣Δ S ∣ = 1$ four-quark operators are matched to the $∣Δ S ∣ = 1$ standard model processes involving the CP phase of the Cabibbo-Kobayashi-Maskawa matrix at the electroweak scale and run down to the hadronic scale $μ = 1$ GeV according to the renormalization group evolution in the next-to-leading logarithmic order. At the hadronic scale, the hadron matrix elements are modeled in the factorization approach. We then obtain the one-meson (pion, eta meson, and kaon) exchange CP-odd nuclear force, which is the combination of the $∣Δ S ∣ = 1$ meson-baryon vertices which issue from the penguin operator and the hyperon-nucleon transition. From this CP-odd nuclear force, the nuclear EDM is calculated with the realistic Argonne $v 18$ interaction and the CP-odd nuclear force using the Gaussian expansion method. It is found that the EDMs of light nuclear systems are of order $O (1 0^{- 31}) e$ cm. We also estimate the standard model contribution to other hadronic CP violating observables such as the EDMs of $^{6}$ Li, $^{9}$ Be nuclei, and the atomic EDMs of $^{129}$ Xe, $^{199}$ Hg, $^{211}$ Rn, and $^{225}$ Ra generated through the nuclear Schiff moment. We then analyze the source of theoretical uncertainties and show some possible ways to overcome them.
Comments:
51 pages, 11 figures, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1512.03013 [pdf]
JHEP(2016)·44 citations
11
[Submitted on 9 Dec 2015] (cross-list from nucl-ex)
Helicity Asymmetry Measurement for $π^{0}$ Photoproduction on the CLAS Frozen Spin Target
Diane Schott🇺🇸 · William Briscoe🇺🇸 · Igor Strakovsky (GWU)🇺🇸
The measurement was performed with circularly polarized photons incident on longitudinally polarized target in Hall B at the Thomas Jefferson National Accelerator Facility. The helicity asymmetry E for $γ p \to π^{0} p$ was determined at CM energies between 1450 MeV and 2050 MeV and compared to the SAID, MAID, and BnGa partial-wave analyses.
Comments:
5 pages, 5 figures; Hadron 2015 Proceedings
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1512.03046 [pdf]
AIP Conf.Proc.(2016)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE