Nuclear Theory·nucl-th

Friday·July 8, 2016

12 papers—5 primary·7 cross-listed

01
[Submitted on 6 Jul 2016]
A practical method in calculating one loop quantum fluctuations to the energy of the non-topological soliton
Song Shu🇨🇳
I have used a practical method to calculate the one-loop quantum correction to the energy of the non-topological soliton in Friedberg-Lee model. The quantum effects which come from the quarks of the Dirac sea scattering with the soliton bag are calculated by a summation of the discrete and continuum energy spectrum of the Dirac equation in the background field of soliton. The phase shift of the continuum spectrum is numerically calculated in an efficient way and all the divergences are removed by the same renormalization procedure.
Comments:
4 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1607.01815 [pdf]
SCPMA(2017)·4 citations
02
[Submitted on 7 Jul 2016]
Auxiliary-field quantum Monte Carlo methods in nuclei
Y. Alhassid
Auxiliary-field quantum Monte Carlo methods enable the calculation of thermal and ground state properties of correlated quantum many-body systems in model spaces that are many orders of magnitude larger than those that can be treated by conventional diagonalization methods. We review recent developments and applications of these methods in nuclei using the framework of the configuration-interaction shell model.
Comments:
28 pages, 10 figures, a chapter in a review book "Emergent Phenomena in Atomic Nuclei from Large-Scale Modeling: a Symmetry-Guided Perspective," ed. K. D. Launey
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); Strongly Correlated Electrons (cond-mat.str-el); Computational Physics (physics.comp-ph)
arXiv:
1607.01870 [pdf]
1 citation
03
[Submitted on 7 Jul 2016]
Nuclear shape phase transition within a conjonction of {\gamma}-rigid and {\gamma}-stable collective behaviours in deformation dependent mass formalism
M. Chabab · A. El Batoul · A. Lahbas · M. Oulne
In this paper, we present a theoretical study of a conjonction of $γ$ -rigid and $γ$ -stable collective motions in critical point symmetries of the phase transitions from spherical to deformed shapes of nuclei using exactly separable version of the Bohr Hamiltonian with deformation-dependent mass term. The deformation-dependent mass is applied simultaneously to $γ$ -rigid and $γ$ -stable parts of this famous collective Hamiltonian. Moreover, the $β$ part of the problem is described by means of Davidson potential, while the $γ$ -angular part corresponding to axially symmetric shapes is treated by a Harmonic Osillator potential. The energy eigenvalues and normalized eigenfunctions of the problem are obtained in compact forms by making use of the asymptotic iteration method. The combined effect of the deformation-dependent mass and rigidity as well as harmonic oscillator stiffness parameters on the energy spectrum and wave functions is duly investigated. Also, the electric quadrupole transition ratios and energy sprectrum of some $γ$ -stable and prolate nuclei are calculated and compared with the experimental data as well as with other theoretical models.
Comments:
22 pages, 5 figures, 7 tables. arXiv admin note: text overlap with arXiv:1506.05782, arXiv:1103.5935 by other authors
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1607.02026 [pdf]
J.Phys.G(2016)·19 citations
04
[Submitted on 7 Jul 2016]
Improved radial basis function approach with the odd-even corrections
Z. M. Niu · B. H. Sun · H. Z. Liang · Y. F. Niu · J. Y. Guo
The radial basis function (RBF) approach has been used to improve the mass predictions of nuclear models. However, systematic deviations exist between the improved masses and the experimental data for nuclei with different odd-even parities of ( $Z$ , $N$ ), i.e., the (even $Z$ , even $N$ ), (even $Z$ , odd $N$ ), (odd $Z$ , even $N$ ), and (odd $Z$ , odd $N$ ). By separately training the RBF for these four different groups, it is found that the systematic odd-even deviations can be cured in a large extend and the predictive power of nuclear mass models can thus be further improved. Moreover, this new approach can better reproduce the single-nucleon separation energies. Based on the latest version of Weizsäcker-Skyrme model WS4, the root-mean-square deviation of the improved masses with respect to known data falls to $135$ keV, approaching the chaos-related unpredictability limit ( $\sim 100$ keV).
Comments:
7 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1607.02075 [pdf]
PRC(2016)·40 citations
05
[Submitted on 7 Jul 2016]
Anharmonicity of multi-octupole-phonon excitations in $^{208}$ Pb: analysis with multi-reference covariant density functional theory and subbarrier fusion of $^{16}$ O+ $^{208}$ Pb
J. M. Yao · K. Hagino
We discuss anharmonicity of the multi-octupole-phonon states in $^{208}$ Pb based on a covariant density functional theory, by fully taking into account the interplay between the quadrupole and the octupole degrees of freedom. Our results indicate the existence of a large anharmonicity in the transition strengths, even though the excitation energies are similar to those in the harmonic limit. We also show that the quadrupole-shape fluctuation significantly enhances the fragmentation of the two-octupole-phonon states in $^{208}$ Pb. Using those transition strengths as inputs to coupled channels calculations, we then discuss the fusion reaction of $^{16}$ O+ $^{208}$ Pb at energies around the Coulomb barrier. We show that the anharmonicity of the octupole vibrational excitation considerably improves previous coupled-channels calculations in the harmonic oscillator limit, significantly reducing the height of the main peak in the fusion barrier distribution.
Comments:
5 pages with 4 figures, to be published in Phys. Rev. C as a Rapid Communication
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1607.02126 [pdf]
PRC(2016)·25 citations
06
[Submitted on 7 Jul 2016] (cross-list from hep-ph)
Resonance decay effect on conserved number fluctuations in a hadron resonance gas model
D. K. Mishra🇮🇳 · P. Garg🇺🇸 · P. K. Netrakanti🇮🇳 · A. K. Mohanty🇮🇳
We study the effect of charged secondaries coming from resonance decay on the net-baryon, net-charge and net-strangeness fluctuations in high energy heavy-ion collisions within the hadron resonance gas (HRG) model. We emphasize the importance of including weak decays along with other resonance decays in the HRG, while comparing with the experimental observables. The effect of kinematic cuts on resonances and primordial particles on the conserved number fluctuations are also studied. The HRG model calculations with the inclusion of resonance decays and kinematical cuts are compared with the recent experimental data from STAR and PHENIX experiments. We find a good agreement between our model calculations and the experimental measurements for both net-proton and net-charge distributions.
Comments:
9 pages, 5 figures, Accepted for publication in Physical Review C
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1607.01875 [pdf]
PRC(2016)·31 citations
07
[Submitted on 7 Jul 2016] (cross-list from hep-ph)
Generalized weak-binding relations of compositeness in effective field theory
Yuki Kamiya🇯🇵 · Tetsuo Hyodo🇯🇵
We study the compositeness of near-threshold states to investigate the internal structure of exotic hadron candidates. Within the framework of effective field theory, Weinberg's weak-binding relation is extended to more general cases by easing several preconditions. First, by evaluating the contribution from the decay channel, we obtain the generalized relation for unstable quasibound states. Next, we generalize the relation to include the nearby CDD (Castillejo-Dalitz-Dyson) pole contribution with the help of the Pade approximant. The validity of the estimation with the generalized weak-binding relations is examined by numerical calculations. The method to systematically evaluate the error in the weak-binding relation is presented. Finally, by applying the extended relation to Lambda(1405), f0(980) and a0(980), we discuss their internal structure, in comparison with other approaches.
Comments:
46 pages, 12 figures, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1607.01899 [pdf]
PTEP(2017)·53 citations
08
[Submitted on 7 Jul 2016] (cross-list from hep-ph)
Probing Transverse Momentum Broadening via Dihadron and Hadron-jet Angular Correlations in Relativistic Heavy-ion Collisions
Lin Chen🇨🇳 · Guang-You Qin🇨🇳 · Shu-Yi Wei🇨🇳 · Bo-Wen Xiao🇨🇳 · Han-Zhong Zhang🇨🇳
Dijet, dihadron, hadron-jet angular correlations have been reckoned as important probes of the transverse momentum broadening effects in relativistic nuclear collisions. When a pair of high-energy jets created in hard collisions traverse the quark-gluon plasma produced in heavy-ion collisions, they become de-correlated due to the vacuum soft gluon radiation associated with the Sudakov logarithms and the medium-induced transverse momentum broadening. For the first time, we employ the systematical resummation formalism and establish a baseline calculation to describe the dihadron and hadron-jet angular correlation data in $pp$ and peripheral $AA$ collisions where the medium effect is negligible. We demonstrate that the medium-induced broadening $⟨ p_{⊥}^{2} ⟩$ and the so-called jet quenching parameter $q^$ can be extracted from the angular de-correlations observed in $AA$ collisions. A global $χ^{2}$ analysis of dihadron and hadron-jet angular correlation data renders the best fit $⟨ p_{⊥}^{2} ⟩ \sim 13 GeV^{2}$ for a quark jet at RHIC top energy. Further experimental and theoretical efforts along the direction of this work shall significantly advance the quantitative understanding of transverse momentum broadening and help us acquire unprecedented knowledge of jet quenching parameter in relativistic heavy-ion collisions.
Comments:
6 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1607.01932 [pdf]
PLB(2017)·91 citations
09
[Submitted on 7 Jul 2016] (cross-list from nucl-th)
Systematic Comparison of Tsallis Statistics for Charged Pions Produced In $pp$ Collisions
A.S. Parvan🇷🇺 · O.V. Teryaev🇷🇺 · J. Cleymans🇿🇦
The energy dependence of Tsallis statistics parameters is presented for charged pions produced at beam energies ranging between 6.3 GeV and 7 TeV. It is found that deviations from Boltzmann statistics are monotonically growing with beam energy. This may be attributed to the dominance of low $x$ at higher energies leading to the power-like NLO QCD spectra for which Tsallis statistics may serve as effective theory. At the same time, for larger $x$ at lower beam energies the Gaussian falloff of transverse-momentum-dependent distributions is crucial and correspondent effective description is provided by the Boltzmann distribution.
Comments:
4 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1607.01956 [pdf]
EPJA(2017)·48 citations
10
[Submitted on 7 Jul 2016] (cross-list from hep-ph)
On the structure observed in the in-flight $^{3} He (K^{-}, Λ p) n$ reaction at J-PARC
Takayasu Sekihara (JAEA, Ibaraki)🇯🇵 · Eulogio Oset (Valencia U. amd Valencia U., IFIC)🇪🇸 · Angels Ramos (Barcelona U. and ICC, Barcelona U.)🇪🇸
A theoretical investigation is done to clarify the origin of the peak structure observed near the $K^{-} pp$ threshold in the in-flight $^{3} He (K^{-}, Λ p) n$ reaction of the J-PARC E15 experiment, which could be a signal of the lightest kaonic nuclei, that is, the $K ˉ N N (I = 1/2)$ state. For the investigation, we evaluate the $Λ p$ invariant mass spectrum assuming two possible scenarios to interpret the experimental peak. One assumes that the $Λ (1405)$ resonance is generated after the emission of an energetic neutron from the absorption of the initial $K^{-}$ , not forming a bound state with the remaining proton. This uncorrelated $Λ (1405) p$ system subsequently decays into the final $Λ p$ . The other scenario implies that, after the emission of the energetic neutron, a $K ˉ N N$ bound state is formed, decaying eventually into a $Λ p$ pair. Our results show that the experimental signal observed in the in-flight $^{3} He (K^{-}, Λ p) n$ reaction at J-PARC is qualitatively well reproduced by the assumption that a $K ˉ N N$ bound state is generated in the reaction, definitely discarding the interpretation in terms of an uncorrelated $Λ (1405) p$ state.
Comments:
27 pages, 18 EPS figures, version accepted for publication in PTEP, discussions on numerical results improved
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1607.02058 [pdf]
PTEP(2016)·58 citations
11
[Submitted on 7 Jul 2016] (cross-list from hep-ph)
Testing the running coupling $k_{T}$ -factorization formula for the inclusive gluon production
F.O. Durães🇧🇷 · A.V. Giannini🇧🇷 · V.P. Goncalves🇸🇪 · F.S. Navarra🇧🇷
The inclusive gluon production at midrapidities is described in the Color Glass Condensate formalism using the $k_{T}$ - factorization formula, which was derived at fixed coupling constant considering the scattering of a dilute system of partons with a dense one. Recent analysis demonstrated that this approach provides a satisfactory description of the experimental data for the inclusive hadron production in $pp / p A / AA$ collisions. However, these studies are based on the fixed coupling $k_{T}$ - factorization formula, which does not take into account the running coupling corrections, which are important to set the scales present in the cross section. In this paper we consider the running coupling corrected $k_{T}$ - factorization formula conjectured some years ago and investigate the impact of the running coupling corrections on the observables. In particular, the pseudorapidity distributions and charged hadrons multiplicity are calculated considering $pp$ , $d A u / pP b$ and $A u A u / P b P b$ collisions at RHIC and LHC energies. We compare the corrected running coupling predictions with those obtained using the original $k_{T}$ - factorization assuming a fixed coupling or a prescription for the inclusion of the running of the coupling. Considering the Kharzeev - Levin - Nardi unintegrated gluon distribution and a simplified model for the nuclear geometry, we demonstrate that the distinct predictions are similar for the pseudorapidity distributions in $pp / p A / AA$ collisions and for the charged hadrons multiplicity in $pp / p A$ collisions. On the other hand, the running coupling corrected $k_{T}$ - factorization formula predicts a smoother energy dependence for $d N / d η$ in $AA$ collisions.
Comments:
9 pages and 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1607.02082 [pdf]
PRD(2016)·17 citations
12
[Submitted on 7 Jul 2016] (cross-list from hep-ph)
Looking for bound states and resonances in the $η^{'} K K ˉ$ system
A. Martínez Torres🇧🇷 · K. P. Khemchandani🇧🇷
Motivated by the continuous experimental investigations of $X (1835)$ in three-body decay channels like $η^{'} π^{+} π^{-}$ , we investigate the $η^{'} K K ˉ$ system with the aim of searching for bound states and/or resonances when the dynamics involved in the $K K ˉ$ subsystem can form the resonances: $f_{0} (980)$ in isospin 0 or $a_{0} (980)$ in isospin 1. For this, we solve the Faddeev equations for the three-body system. The input two-body $t$ -matrices are obtained by solving Bethe-Salpeter equations in a coupled channel formalism. As a result, no signal of a three-body bound state or resonance is found.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1607.02102 [pdf]
PRD(2016)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE