Nuclear Theory·nucl-th

Tuesday·January 6, 2015

6 papers—4 primary·2 cross-listed

01
The internal structures of the nucleon resonances $N (1875)$ and $N (2120)$
Jun He🇨🇳
A nucleon resonance with spin-parity $J^{P} = 3/ 2^{-}$ and mass about 2.1 GeV is essential to reproduce the photoproduction cross sections for $Λ (1520)$ released by the LEPS and CLAS Collaborations. It can be explained as the third nucleon resonance state $[3/ 2^{-}]_{3}$ in the constituent quark model so that there is no position to settle the $N (1875)$ which is listed in the PDG as the third $N 3/ 2^{-}$ nucleon resonance. An interpretation is proposed that the $N (1875)$ is from the interaction of a decuplet baryon $Σ (1385)$ and a octet meson $K$ , which is favored by a calculation of binding energy and decay pattern in a Bethe-Salpeter approach.
nucl-thhep-lathep-phnucl-exPRC(2015)·45 citations
02
Dirac Phenomenological Analyses of Unpolarized Proton Inelastic Scattering from $^{22}$ Ne
Moon-Won Kim · Sugie Shim
Unpolarized 800 MeV proton inelastic scatterings from an s-d shell nucleus $^{22}$ Ne are analyzed using phenomenological optical potentials in the Dirac coupled channel formalism. The first-order rotational collective model is used to obtain the transition optical potentials for the low lying excited collective states that belong to the ground state rotational band of the nucleus. The optical potential parameters of Woods-Saxon shape and the deformation parameters of the excited states are varied phenomenologically using the sequential iteration method to reproduce the experimental differential cross section data. The effective central and spin-orbit optical potentials are obtained by reducing the Dirac equations to the Schrödinger-like second-order differential equations and the surface-peaked phenomena are observed at the real effective central potentials when the scattering from $^{22}$ Ne is considered. The obtained deformation parameters of the excited states are compared with those of the nonrelativistic calculations and another s-d shell nucleus $^{20}$ Ne. The deformation parameters for the $2^{+}$ and the $4^{+}$ states of the ground state rotational band at the nucleus $^{22}$ Ne are found to be smaller than those of $^{20}$ Ne, indicating that the couplings of those states to the ground state are weaker at the nucleus $^{22}$ Ne compared to those at the nucleus $^{20}$ Ne. The multistep channel coupling effect is confirmed to be important for the $4^{+}$ state excitation of the ground state rotational band at the proton inelastic scattering from the s-d shell nucleus $^{22}$ Ne.
nucl-thJ.Korean Phys.Soc.(2015)·4 citations
03
Anisotropic flow generated by hard partons in medium
Boris Tomasik🇸🇰 · Martin Schulc🇨🇿
Hard partons which are produced copiously in nuclear collisions at the LHC, deposit most of their energy and momentum into the surrounding quark-gluon plasma. We show that this generates streams in the plasma and contributes importantly to flow anisotropies. With the help of event-by-event three-dimensional perfect hydrodynamic simulations we calculate the observable azimuthal anisotropies of hadronic distributions and show that the proposed mechanism is capable of generating non-negligible part of the observed signal. Hence, it must be taken into account in quantitative studies in which one tries to extract the values of viscosities from the comparison of simulated results with measured data.
nucl-thhep-ph0 citations
04
Analytical solution for the Davydov-Chaban Hamiltonian with sextic potential for $γ = 3 0^{\circ}$
P. Buganu · R. Budaca
An analytical solution for the Davydov-Chaban Hamiltonian with a sextic oscillator potential for the variable $β$ and $γ$ fixed to $3 0^{\circ}$ , is proposed. The model is conventionally called Z(4)-Sextic. For the considered potential shapes the solution is exact for the ground and $β$ bands, while for the $γ$ band an approximation is adopted. Due to the scaling property of the problem the energy and $B (E 2)$ transition ratios depend on a single parameter apart from an integer number which limits the number of allowed states. For certain constraints imposed on the free parameter, which lead to simpler special potentials, the energy and $B (E 2)$ transition ratios are parameter independent. The energy spectra of the ground and first $β$ and $γ$ bands as well as the corresponding $B (E 2)$ transitions, determined with Z(4)-Sextic, are studied as function of the free parameter and presented in detail for the special cases. Numerical applications are done for the $^{128, 130, 132}$ Xe and $^{192, 194, 196}$ Pt isotopes, revealing a qualitative agreement with experiment and a phase transition in Xe isotopes.
nucl-thPRC(2015)·72 citations

Affiliations

first authorsco-authorsvia INSPIRE

The internal structures of the nucleon resonances N(1875) and N(2120)

Dirac Phenomenological Analyses of Unpolarized Proton Inelastic Scattering from 22Ne

Anisotropic flow generated by hard partons in medium

Analytical solution for the Davydov-Chaban Hamiltonian with sextic potential for γ=30∘

Affiliations

The internal structures of the nucleon resonances $N (1875)$ and $N (2120)$

Dirac Phenomenological Analyses of Unpolarized Proton Inelastic Scattering from $^{22}$ Ne

Analytical solution for the Davydov-Chaban Hamiltonian with sextic potential for $γ = 3 0^{\circ}$