Nuclear Theory·nucl-th

Wednesday·December 6, 2017

9 papers—7 primary·2 cross-listed

01
Quantification of Chiral Magnetic Effect from Event-by-Event Anomalous-Viscous Fluid Mechanics
Shuzhe Shi🇺🇸 · Yin Jiang🇨🇳 · Elias Lilleskov🇺🇸 · Jinfeng Liao🇺🇸
Chiral Magnetic Effect (CME) is the macroscopic manifestation of the fundamental chiral anomaly in a many-body system of chiral fermions, and emerges as anomalous transport current in hydrodynamic framework. Experimental observation of CME is of great interest and significant efforts have been made to look for its signals in heavy ion collisions. Encouraging evidence of CME-induced charge separation has been reported from both RHIC and LHC, albeit with ambiguity due to potential background contributions. Crucial for addressing such issue, is the need of quantitative predictions for both CME signal and the non-CME background consistently, with sophisticated modeling tool. In this contribution we report a recently developed Anomalous Viscous Fluid Dynamics (AVFD) framework, which simulates the evolution of fermion currents in QGP on top of the data-validated VISHNU bulk hydro evolution. In particular, this framework has been extended to event-by-event simulations with proper implementation of known flow-driven background contributions. We report quantitative results from such simulations and evaluate the implications for interpretations of current experimental measurements. Finally we give our prediction for the CME signal in upcoming isobaric collisions.
nucl-thhep-phPoS(2018)·4 citations
02
Inclusive breakup calculations in angular momentum basis: application to $^{7}$ Li+ $^{58}$ Ni
Jin Lei🇺🇸
The angular momentum basis method is introduced to solve the inclusive breakup within the model proposed by Ichimura, Austern, and Vincent [Phys. Rev. C 32, 431 (1985)]. This method is based on the geometric transformation between Jacobi coordinates, thus it is easy to corporate with particle spins. To test the validity of this partial wave expansion method, a benchmark calculation is done comparing with the one given in [Phys. Rev. C 92, 044616 (2015)]. Using the distorted-wave Born approximation (DWBA) version of IAV model, some applications to $^{7}$ Li reactions are presented and compared with available data.
nucl-thPRC(2018)·11 citations
03
Approximate Solution of Bohr-Mottelson Hamiltonian with Minimal Length Effect for Hulthen Potential Using Asymptotic Iteration Method
Isnaini Lilis Elviyanti · A Suparmi · C Cari
The approximate solution of Bohr-Mottelson Hamiltonian in rigid deformed nucleus case for Hulthen potential with minimal length effect was investigated using Asymptotic Iteration Method. Asymptotic Iteration Method was used to solve approximately the Bohr-Mottelson Hamiltonian to obtain energy spectrum and un-normalized wave function. The energy spectrum was calculated numerically using the Matlab software. The un-normalized wave function was expressed in the hypergeometric term. The results showed that the energy spectrum increased due to the increasing minimal length parameter. The energy spectrum also increased by the increasing range of potential.
nucl-th0 citations
04
Value of the axial-vector coupling strength in $β$ and $β β$ decays: A review
Jouni Suhonen🇫🇮
In this review the quenching of the weak axial-vector coupling strength, $g_{A}$ , is discussed in nuclear $β$ and double- $β$ decays. On one hand, the nuclear-medium and nuclear many-body effects are separated, and on the other hand the quenching is discussed from the points of view of different many-body methods and different $β$ -decay and double- $β$ -decay processes. Both the historical background and the present status are reviewed and contrasted against each other. The theoretical considerations are tied to performed and planned measurements, and possible new measurements are urged, whenever relevant and doable. Relation of the quenching problem to the measurements of charge-exchange reactions and muon-capture rates is pointed out.
nucl-thhep-phFront.in Phys.(2017)·211 citations
05
Kinetic equations and anisotropic hydrodynamics for quark and gluon fluids
Ewa Maksymiuk🇵🇱
The mixture of quark and gluon fluids is studied in a one-dimensional boost-invariant setup using the set of relativistic kinetic equations treated in the relaxation time approximation. Effects of a finite quark mass, non-zero baryon number density, and quantum statistics are discussed. Comparisons between the exact kinetic-theory results and anisotropic hydrodynamics predictions are performed and a very good agreement between the two are found.
nucl-thEPJ Web Conf.(2018)·1 citation
06
Baryon Chiral Perturbation Theory combined with the $1/ N_{c}$ Expansion in SU(3) I: Framework
Ishara P. Fernando🇺🇸 · Jose L. Goity🇺🇸
Baryon Chiral Perturbation Theory combined with the $1/ N_{c}$ expansion is implemented for three flavors. Baryon masses, vector charges and axial vector couplings are studied to one-loop and organized according to the $ξ$ -expansion, in which the $1/ N_{c}$ and the low energy power countings are linked according to $1/ N_{c} = O (ξ) = O (p)$ . The renormalization to $O (ξ^{3})$ necessary for the mentioned observables is provided, along with applications to the baryon masses and axial couplings as obtained in lattice QCD calculations.
nucl-thhep-phPRD(2018)·10 citations
07
Richardson-Gaudin Configuration-Interaction for nuclear pairing correlations
Stijn De Baerdemacker · Pieter W. Claeys · Jean-Sébastien Caux · Dimitri Van Neck · Paul W. Ayers
Background: The nuclear many-body system is a strongly correlated quantum system, posing serious challenges for perturbative approaches starting from uncorrelated reference states. The last decade has witnessed considerable progress in the accurate treatment of pairing correlations, one of the major components in medium-sized nuclei, reaching accuracies below the 1% level of the correlation energy. Purpose: Development of a quantum many-body method for pairing correlations that is (a) competitive in the 1% error range, and (b) can be systematically improved with a fast (exponential) convergence rate. Method: The present paper capitalizes upon ideas from Richardson-Gaudin integrability. The proposed method is a two-step approach. The first step consists of the optimization of a Richardson-Gaudin ground state as variational trial state. At the second step, the complete set of excited states on top of this Richardson-Gaudin ground state is used as an optimal basis for a Configuration Interaction method in an increasingly large effective Hilbert space. Results: The performance of the variational Richardson-Gaudin (varRG) and Richardson-Gaudin Configuration Interaction (RGCI) method is benchmarked against exact results using an effective $G$ -matrix interaction for the Sn region. The varRG already reaches accuracies around the 1% level of the correlation energies, and the RGCI step sees an additional improvement scaling exponentially with the size of the effective Hilbert space. Conclusions: The Richardson-Gaudin models of integrability provide an optimized complete basis set for pairing correlations.
nucl-thnlin.SI3 citations
08
Effects of Renormalizing the chiral SU(2) Quark-Meson-Model
Andreas Zacchi🇩🇪 · Jürgen Schaffner-Bielich🇩🇪
We investigate the restoration of chiral symmetry at finite temperature in the SU(2) quark meson model where the mean field approximation is compared to the renormalized version for quarks and mesons. In a combined approach at finite temperature all the renormalized versions show a crossover transition. The inclusion of different renormalization scales leave the order parameter and the mass spectra nearly untouched, but strongly influence the thermodynamics at low temperatures and around the phase transition. We find unphysical results for the renormalized version of mesons and the combined one.
↳ hep-phnucl-thPRD(2018)·17 citations
09
A modification of Faddeev-Popov approach free from Gribov ambiguity
Chong-yao Chen🇨🇳 · Fei Gao🇨🇳 · Yu-xin Liu🇨🇳
We propose a modified version of the Faddeev-Popov quantization approach for non-Abelian gauge field theory to avoid the Gribov ambiguity. We show that by means of introducing a new method to insert the correct identity into the Yang-Mills generating functional and considering the identity generated by an integral through a subgroup of the gauge group, the problem of the Gribov ambiguity can be removed naturally. Meanwhile by handling the absolute value of the Faddeev-Popov determinant with the method introduced by Williams and collaborators, we lift the Jacobian determinant together with the absolute value and obtain a local Lagrangian. The new Lagrangian have a nilpotent symmetry which can be viewed as an analogue of the BRST symmetry.
↳ hep-thhep-phnucl-thCommun.Theor.Phys.(2020)·1 citation

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