Nuclear Theory·nucl-th

Tuesday·April 24, 2018

14 papers—8 primary·6 cross-listed

01
Towers of baryons of the $N = 2$ quark model band in the large $N_{c}$ limit
C.T. Willemyns🇦🇷 · N.N. Scoccola🇦🇷
We performed a complete analysis of the spectrum of all the states in the $N = 2$ quark model harmonic oscillator band with $N_{f} = 3$ in the large $N_{c}$ limit including the often disregarded antisymmetric multiplet $[20, 1^{+}]$ . We included configuration mixing effects. We found that the states in the $[56, L^{+}]$ and $[70, L^{+}]$ with $L = 0, 2$ fall into nine towers of degenerate states. We found that nonstrange antisymmetric states fall into three towers and respond to the same structure as the states in the $[70, 1^{-}]$ multiplet. We also showed explicitly the compatibility of these results and the scattering resonance picture.
nucl-thhep-lathep-phPRD(2018)·1 citation
02
Hadron Spectra, Decays and Scattering Properties within Basis Light Front Quantization
James P. Vary🇺🇸 · Lekha Adhikari🇺🇸 · Guangyao Chen🇺🇸 · Shaoyang Jia🇺🇸 · Meijian Li🇺🇸 · Yang Li🇺🇸 · Pieter Maris🇺🇸 · Wenyang Qian🇺🇸 · John R. Spence🇺🇸 · Shuo Tang🇺🇸 · Kirill Tuchin🇺🇸 · Anji Yu🇺🇸 · Xingbo Zhao🇺🇸
We survey recent progress in calculating properties of the electron and hadrons within the Basis Light Front Quantization (BLFQ) approach. We include applications to electromagnetic and strong scattering processes in relativistic heavy ion collisions. We present an initial investigation into the glueball states by applying BLFQ with multigluon sectors, introducing future research possibilities on multi-quark and multi-gluon systems.
nucl-thFew Body Syst.(2018)·16 citations
03
Reexamine the nuclear chiral geometry from the orientation of the angular momentum
Q. B. Chen · J. Meng
The paradox on the previous interpretation for the nuclear chiral geometry based on the effective angle has been clarified by reexamining the system with the particle-hole configuration $π (1 h_{11/2})^{1} \otimes ν (1 h_{11/2})^{- 1}$ and rotor with deformation parameter $γ = 3 0^{\circ}$ . It is found that the paradox is caused by the fact that the angular momentum of the rotor is much smaller than those of the proton and the neutron near the bandhead. Hence, it does not support a chiral rotation interpretation near the bandhead. The nuclear chiral geometry based on the effective angle makes sense only when the angular momentum of the rotor becomes comparable with those of the proton and the neutron at the certain spin region.
nucl-thnucl-exPRC(2018)·41 citations
04
Single- and two-nucleon momentum distributions for local chiral interactions
D. Lonardoni · S. Gandolfi · X. B. Wang · J. Carlson
We present quantum Monte Carlo calculations of the single- and two-nucleon momentum distributions in selected nuclei for $A \leq 16$ . We employ local chiral interactions at next-to-next-to-leading order. We find good agreement at low momentum with the single-nucleon momentum distributions derived for phenomenological potentials. The same agreement is found for the integrated two-nucleon momentum distributions at low relative momentum $q$ and low center-of-mass momentum $Q$ . We provide results for the two-nucleon momentum distributions as a function of both $q$ and $Q$ . The large ratio of $p n$ to $pp$ pairs around $q = 2 f m^{- 1}$ for back-to-back $(Q = 0)$ pairs is confirmed up to $^{16}$ O, and results are compatible with those extracted from available experimental data.
nucl-thPRC(2018)·26 citations
05
Single-pole Nature of the Detectable Lambda(1405)
K. S. Myint🇲🇲 · Y. Akaishi🇯🇵 · M. Hassanvand🇯🇵 · T. Yamazaki🇯🇵
We have investigated the single-pole nature of the detectable Lambda(1405) in detail, by employing a chiral model having double poles of a KbarN-piSigma coupled channel T-matrix. The effects of the 1st pole and the 2nd pole on the observed piSigma mass spectrum in the Lambda(1405) region were analyzed separately by means of the Generalized Optical Potential. It is concluded that the 1st pole is responsible for both peak structures seen in the T(piSigma leftarrow KbarN)(T(21)) and T(piSigma leftarrow piSigma)(T(22)) invariant-mass spectra, and the 2nd pole due to an energy-dependent chiral interaction provides continuum amplitudes affecting the shape of peak structures in experimentally observable spectrum of the Lambda(1405).
nucl-thPTEP(2018)·13 citations
06
Relativistic Dissipative Fluid Dynamics from Non-Equilibrium Statistical Operator
Arus Harutyunyan🇩🇪 · Armen Sedrakian🇩🇪 · Dirk H. Rischke🇩🇪
We present a new derivation of second-order relativistic dissipative fluid dynamics for quantum systems using Zubarev's formalism for the non-equilibrium statistical operator. In particular, we discuss the shear-stress tensor to second order in gradients and argue that the relaxation terms for the dissipative quantities arise from memory effects contained in the statistical operator. We also identify new transport coefficients which describe the relaxation of dissipative processes to second order and express them in terms of equilibrium correlation functions, thus establishing Kubo-type formulae for the second-order transport coefficients.
nucl-thhep-phParticles(2018)·18 citations
07
Construction of a local barK N-pi Sigma-pi Lambda potential and composition of the Lambda(1405)
Kenta Miyahara🇯🇵 · Tetsuo Hyodo🇯🇵 · Wolfram Weise🇩🇪
A Kbar N-pi Sigma-pi Lambda coupled-channel potential is constructed on the basis of chiral SU(3) dynamics. Several matching conditions are introduced to formulate an equivalent local potential that reproduces the coupled-channel scattering amplitudes resulting from chiral SU(3)_L times SU(3)_R meson-baryon effective field theory. In contrast to a previously constructed effective single-channel Kbar N potential, the explicit treatment of the pi Sigma channel yields a natural description of the low-mass pole as part of the two-pole structure of the Lambda(1405) resonance. The energy dependence of the potential can now be parametrized with a minimum of polynomial orders. To study the properties of the Lambda(1405) as a quantum-mechanical quasibound state, we derive the normalization condition of its wave function generated by the energy-dependent coupled-channel potential, using the Feshbach projection method. This framework provides an improved understanding of this system from the viewpoint of the compositeness of hadrons. With the properly normalized wave function, we demonstrate and confirm that the high-mass pole of the Lambda(1405) is dominated by the Kbar N component.
nucl-thhep-phPRC(2018)·44 citations
08
Particle number conserving BCS approach in the relativistic mean field model and its application to $^{32 - 74}$ Ca
Rong An · Lisheng Geng · Shisheng Zhang · Lang Liu
A particle number conserving BCS approach (FBCS) is formulated in the relativistic mean field (RMF) model. It is shown that the so-obtained RMF+FBCS model can describe the weak pairing limit. We calculate the ground-state properties of the calcium isotopes $^{32 - 74}$ Ca and compare the results with those obtained from the usual RMF+BCS model. Although the results are quite similar to each other, we observe an interesting phenomenon, i.e., for $^{54}$ Ca, the FBCS approach can enhance the occupation probability of the $2 p_{1/2}$ single particle level and slightly increases its radius, compared with the RMF+BCS model. This leads to an unusual scenario that although $^{54}$ Ca is more bound with a spherical configuration but the corresponding size is not the most compact one. We anticipate that such a phenomenon might happen for other neutron rich nuclei and should be checked by further more systematic studies.
nucl-thnucl-exCPC(2018)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE