Nuclear Theory·nucl-th

Friday·February 17, 2017

8 papers—6 primary·2 cross-listed

01
[Submitted on 15 Feb 2017]
Hot magnetized nuclear matter: Thermodynamic and Saturation Properties
Z. Rezaei · G. H. Bordbar
We have used a realistic nuclear potential, AV18, and a many body technique, the lowest order constraint variational (LOCV) approach, to calculate the properties of hot magnetized nuclear matter. By investigating the free energy, spin polarization parameter, and symmetry energy, we have studied the temperature and magnetic field dependence of the saturation properties of magnetized nuclear matter. In addition, we have calculated the equation of state of magnetized nuclear matter at different temperatures and magnetic fields. It was found that the flashing temperature of nuclear matter decreases by increasing the magnetic field. In addition, we have studied the effect of the magnetic field on liquid gas phase transition of nuclear matter. The liquid gas coexistence curves, the order parameter of the liquid gas phase transition, and the properties of critical point at different magnetic fields have been calculated.
Comments:
30 pages, 13 figures, 2 tables. Accepted for publication in European Physical Journal A
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
1702.04765 [pdf]
EPJA(2017)·4 citations
02
[Submitted on 16 Feb 2017]
Three-body decay of linear-chain states in $^{14}$ C
Tomoyuki Baba · Masaaki Kimura
The decay properties of the linear-chain states in $^{14}$ C are investigated by using the antisymmetrized molecular dynamics. The calculation predicts two rotational bands with linear-chain configurations having the $π$ -bond and $σ$ -bond valence neutrons. For the $π$ -bond linear-chain, the calculated excitation energies and the widths of $α$ -decay to the ground state of $^{10} Be$ reasonably agree with the experimental candidates observed by the $α +^{10} Be$ resonant scattering. On the other hand, the $σ$ -bond linear-chain is the candidate of the higher-lying resonant states reported by the break-up reaction. As the evidence of the $σ$ -bond linear-chain, we discuss its decay pattern. It is found that the $σ$ -bond linear-chain not only decays to the excited band of $^{10} Be$ but also decays to the three-body channel of $^{6} He + α + α$ , and the branching ratio of these decays are comparable. Hence, we suggest that this characteristic decay pattern is a strong signature of the linear-chain formation and a key observable to distinguish two different linear-chains.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1702.04874 [pdf]
PRC(2017)·28 citations
03
[Submitted on 16 Feb 2017]
Structural evolution in germanium and selenium nuclei within the mapped interacting boson model based on the Gogny energy density functional
K. Nomura · R. Rodríguez-Guzmán · L. M. Robledo
The shape transitions and shape coexistence in the Ge and Se isotopes are studied within the interacting boson model (IBM) with the microscopic input from the self-consistent mean-field calculation based on the Gogny-D1M energy density functional. The mean-field energy surface as a function of the quadrupole shape variables $β$ and $γ$ , obtained from the constrained Hartree-Fock-Bogoliubov method, is mapped onto the expectation value of the IBM Hamiltonian with configuration mixing in the boson condensate state. The resultant Hamiltonian is used to compute excitation energies and electromagnetic properties of the selected nuclei $^{66 - 94}$ Ge and $^{68 - 96}$ Se. Our calculation suggests that many nuclei exhibit $γ$ softness. Coexistence between prolate and oblate, as well as between spherical and $γ$ -soft, shapes is also observed. The method provides a reasonable description of the observed systematics of the excitation energy of the low-lying energy levels and transition strengths for nuclei below the neutron shell closure $N = 50$ , and provides predictions on the spectroscopy of neutron-rich Ge and Se isotopes with $52 \leq N \leq 62$ , where data are scarce or not available.
Comments:
16 pages, 20 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1702.04879 [pdf]
PRC(2017)·57 citations
04
[Submitted on 16 Feb 2017]
Muon-neutrino-induced charged current pion production on nuclei
U. Mosel · K. Gallmeister
[Background] Long-Baseline experiments such as T2K, NOvA or the planned Deep Underground Neutrino Experiment (DUNE) require theoretical descriptions of the complete event in a neutrino-nucleus reaction. Since nuclear targets are used this requires a good understanding of neutrino-nucleus interactions. [Purpose] One of the dominant reaction channels in neutrino-nucleus interactions is pion production. This paper aims for a coherent view on all charged current charged pion production data that are avaible from the experiments MiniBooNE, the near detector experiment at T2K and MINERvA. [Methods] Pion production is treated through excitations of nucleon resonances, including background terms, and deep inelastic scattering. The final state interactions of the produced pions are described within the Giessen-Boltzmann-Uehling-Uhlenbeck (GiBUU) implementation of quantum-kinetic transport theory. [Results] Results are given for MiniBooNE, the near detector experiment at T2K and for MINERvA. While the theoretical results for MiniBooNE differ from the data both in shape and magnitude, their agreement both with the T2K and the MINERvA data is good for all pion and lepton observables. Predictions for pion spectra are shown for MicroBooNE and NOvA. [Conclusions] Based on the GiBUU model of lepton-nucleus interactions a consistent, good theoretical description of CC charged pion production data from the T2K ND and the MINERvA experiments is possible, without any parameter tunes. The MiniBooNE data cannot be reproduced.
Comments:
Version accepted for publication in Phys. Rev. C. Short discussion of the essential features of GiBUU 2016 is added as well as a short investigation of many-pion events. For NOvA one new figure is added that shows pion spectra with and without fsi both for H and for C
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1702.04932 [pdf]
Phys. Rev. C 96, 015503 (2017)
05
[Submitted on 16 Feb 2017]
Algorithm for the asymptotic nuclear coefficients calculations using phase shift data for charged particles scattering
Yu. V. Orlov · B. F. Irgaziev · Jameel-Un Nabi
A new algorithm for the asymptotic nuclear coefficients calculation, which we call the $Δ$ -method, is proved and developed. This method was proposed in Ref. [O. L. Ramírez Suárez and J.-M. Sparenberg, arXiv: 1602.04082 [nucl-th] (2016)] but no proof was given. We apply it to the bound state situated near the channel threshold when the Sommerfeld parameter is quite large within the experimental energy region. As a result, the value of the conventional effective-range function $K_{l} (k^{2})$ is actually defined by the Coulomb term. One of the resulting effects is the wrong description of energy behavior of the elastic scattering phase shift $δ_{l}$ reproduced from the fitted total effective-range function $K_{l} (k^{2})$ . This leads to an improper value of the asymptotic normalization coefficient (ANC) value. No such problem arises if we fit only the nuclear term. The difference between the total effective-range function and the Coulomb part at real energies is the same as the nuclear term. Then we can proceed using just this $Δ$ -method to calculate the pole position values and the ANC. We apply it to the vertices $^{4} He +^{12} C ⟷^{16} O$ and $^{3} He +^{4} He ⟷^{7} Be$ . The calculated ANCs can be used to find the radiative capture reaction cross sections of the transfers to the $^{16} O$ bound final states as well as to the $^{7} Be ⟷^{7} Be$ . The calculated ANCs can be used to find the radiative capture reaction cross sections of the transfers to the $^{16} O$ bound final states as well as to the $^{7} Be$ .
Comments:
11 pages, 6 figures, 1 table
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1702.04933 [pdf]
PRC(2017)·27 citations
06
[Submitted on 16 Feb 2017]
Influence of target deformation and deuteron breakup in (d,p) transfer reactions
M. Gomez-Ramos · A. M. Moro
The effect of core excitations in transfer reactions of the form A(d, p)B has been found to affect significantly the calculated cross sections and to depend strongly and non-linearly on the incident deuteron energy in Faddeev/AGS calculations. Our goal is to investigate these effects within a coupled-channels formulation of the scattering problem which, in addition of being computationally less demanding than the Faddeev counterpart, may help shed some light into the physical interpretation of the cited effects. We use an extended version of the continuum-discretized coupled-channels (CDCC) method with explicit inclusion of target excitations within a coupled-channels Born approximation (CDCC-BA) formulation of the transfer transition amplitude. We compare the calculated transfer cross sections with those obtained with an analogous calculation omitting the effect of target excitation. We consider also an adiabatic coupled channels (ACC) method. Our working example is the 10 Be(d,p) 11 Be reaction. We find that both formalisms are able to reproduce the effects of deformation found in Faddeev calculations, whose origin stems from the interference of the direct one-step transfer, and the two-step transfer following target excitation.
Comments:
8 pages, 6 figures, submitted to Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1702.04954 [pdf]
PRC(2017)·19 citations
07
[Submitted on 13 Feb 2017] (cross-list from hep-ph)
Elliptic flow from color-dipole orientation in pp and pA collisions
Edmond Iancu🇫🇷 · Amir H. Rezaeian🇨🇱
For ultrarelativistic proton-proton and proton-nucleus collisions, we perform an exploratory study of the contribution to the elliptic flow $v_{2}$ coming from the orientation of the momentum of the produced particles with respect to the reaction plane. Via the CGC factorization valid at high energies, this contribution is related to the orientation of a color dipole with respect to its impact parameter, which in turn probes the transverse inhomogeneity in the target. Using the McLerran-Venugopalan model (with impact-parameter dependence) as an effective description for the soft gluon distribution in the (proton or nuclear) target, we present a semi-analytic calculation of the dipole scattering amplitude, including its angular dependence. We find that the angular dependence is controlled by soft gluon exchanges and hence is genuinely non-perturbative. The effects of multiple scattering turn out to be essential (in particular, they change the sign of $v_{2}$ ). We find that sizable values for $v_{2}$ , comparable to those observed in the LHC data and having a similar dependence upon the transverse momenta of the produced particles, can be easily generated via peripheral collisions. In particular, $v_{2}$ develops a peak at a transverse momentum which scales with the saturation momentum in the target.
Comments:
28 pages, 22 figures; v2: extended version, new discussion about the relation between elliptic flow and eccentricity, 8 new plots and some additional references added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1702.03943 [pdf]
PRD(2017)·63 citations
08
[Submitted on 16 Feb 2017] (cross-list from hep-ph)
Effect of Quark Dimension Reduction on Goldstone Mode in Magnetic Field
Shijun Mao🇨🇳 · Yuxuan Wang🇨🇳
The meson static properties are investigated in Pauli-Villars regularized Nambu--Jona-Lasinio model in strong magnetic field. The quark dimension reduction leads to not only the magnetic catalysis effect on chiral symmetry restoration but also a sudden jump of the mass of the Goldstone mode at the Mott transition temperature.
Comments:
5 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1702.04868 [pdf]
PRD(2017)·46 citations

Affiliations

first authorsco-authorsvia INSPIRE