Nuclear Theory·nucl-th

Wednesday·April 1, 2015

6 papers—3 primary·3 cross-listed

01
Study of in-medium $η^{'}$ properties in the ( $γ$ , $η^{'} p$ ) reaction on nuclei
E. Ya. Paryev🇷🇺
We study the near-threshold photoproduction of $η^{'}$ mesons from nuclei in coincidence with forward going protons in the kinematical conditions of the Crystal Barrel/TAPS experiment, recently performed at ELSA. The calculations have been performed within a collision model based on the nuclear spectral function. The model accounts for both the primary $γ p \to η^{'} p$ process and the two-step intermediate nucleon rescattering processes as well as the effect of the nuclear $η^{'}$ mean-field potential. We calculate the exclusive $η^{'}$ kinetic energy distributions for the $^{12}$ C( $γ$ , $η^{'} p$ ) reaction for different scenarios of $η^{'}$ in-medium modification. We find that the considered two-step rescattering mechanism plays an insignificant role in $η^{'} p$ photoproduction off the carbon target. We also demonstrate that the calculated $η^{'}$ kinetic energy distributions in primary photon--proton $η^{'} p$ production reveal strong sensitivity to the depth of the real $η^{'}$ potential at normal nuclear matter density (or to the $η^{'}$ in-medium mass shift) in the studied incident photon energy regime. Therefore, such observables may be useful to help determine the above $η^{'}$ in-medium renormalization from the comparison of the results of our calculations with the data from the CBELSA/TAPS experiment. In addition, we show that these distributions are also strongly influenced by the momentum-dependent optical potential, which the outgoing participant proton feels inside the carbon nucleus. This potential should be taken into account in the analysis of these data with the aim to obtain information on the $η^{'}$ modification in cold nuclear matter.
nucl-thnucl-exJ.Phys.G(2016)·6 citations
02
Shape coexistence and evolution in neutron-deficient krypton isotopes
Z. J. Bai · X. M. Fu · C. F. Jiao · F. R. Xu
Total Routhian Surface (TRS) calculations have been performed to investigate shape coexistence and evolution in neutron-deficient krypton isotopes $^{72, 74, 76}$ Kr. The ground-state shape is found to change from oblate in $^{72}$ Kr to prolate in $^{74, 76}$ Kr, in agreement with experimental data. Quadrupole deformations of the ground states and coexisting $0_{2}^{+}$ states as well as excitation energies of the latter are also well reproduced. While the general agreement between calculated moments of inertia and those deduced from observed spectra confirms the prolate nature of the low-lying yrast states of all three isotopes (except the ground state of $^{72}$ Kr), the deviation at low spins suggests significant shape mixing. The role of triaxiality in describing shape coexistence and evolution in these nuclei is finally discussed.
nucl-thCPC(2015)·10 citations
03
Multiquark interactions and heavy hybrid stars
Sanjin Benić🇯🇵
We introduce a two flavor Nambu--Jona-Lasinio (NJL) model with 8-quark interactions in the scalar and the vector channel. With the lower density region described by the density-dependent relativistic mean field model we construct a hybrid equation of state. We especially focus on the 4-quark vector couplings and the 8-quark vector NJL couplings and allocate a region in this parameter subspace where hybrid stars with masses larger than $2 M_{⊙}$ exist.
nucl-thastro-ph.HEhep-ph0 citations
04
Complete plasmon spectrum of two-stream system
Katarzyna Deja🇵🇱 · Stanislaw Mrowczynski🇵🇱
The complete spectrum of plasmons of the two interpenetrating plasma streams is found in a closed analytic form. The orientation of the wave vector with respect to the stream direction is arbitrary and the plasmas, which are assumed to be collisionless and spatially homogeneous, can be nonrelativistic, relativistic or even ultrarelativistic. Our results apply to the electromagnetic plasma of electrons and passive ions and to the quark-gluon plasma governed by QCD.
↳ hep-phnucl-thActa Phys.Polon.B(2015)·1 citation
05
Effects of the interaction between the magnetic moments on the energy levels of a pionic atom
Voicu Dolocan🇷🇴
We present the calculation of the binding energy of 2p pion for various central charges Z. We have taken into account the interaction between the magnetic moment of the nucleus and the orbital magnetic moment of the pion. The obtained results show that the interaction between the magnetic moments decreases teh binding energy. This decrease is larger when the two magnetic moments add one another. Also, the binding energy increases with Z increasing.
↳ physics.gen-phnucl-th0 citations
06
Light Quarks in the Screened Dyon-Anti-Dyon Coulomb Liquid Model II
Yizhuang Liu🇺🇸 · Edward Shuryak🇺🇸 · Ismail Zahed🇺🇸
We discuss an extension of the dyon-anti-dyon liquid model that includes light quarks in the dense center symmetric Coulomb phase. In this work, like in our previous one, we use the simplest color SU(2) group. We start with a single fermion flavor $N_{f} = 1$ and explicitly map the theory onto a 3-dimensional quantum effective theory with a fermion that is only U $_{V} (1)$ symmetric. We use it to show that the dense center symmetric plasma develops, in the mean field approximation, a nonzero chiral condensate, although the ensuing Goldstone mode is massive due to the U $_{A} (1)$ axial-anomaly. We estimate the chiral condensate and $σ, η$ meson masses for $N_{f} = 1$ . We then extend our analysis to several flavors $N_{f} > 1$ and colors $N_{c} > 2$ and show that center symmetry and spontaneous chiral symmetry breaking disappear simultaneously when $x = N_{f} / N_{c} \geq 2$ in the dense plasma phase. A reorganization of the dense plasma phase into a gas of dyon-antidyon molecules restores chiral symmetry, but may preserve center symmetry in the linearized approximation. We estimate the corresponding critical temperature.
↳ hep-phhep-lathep-thnucl-thPRD(2015)·59 citations

Affiliations

first authorsco-authorsvia INSPIRE

Study of in-medium η′ properties in the (γ, η′p) reaction on nuclei

Shape coexistence and evolution in neutron-deficient krypton isotopes

Multiquark interactions and heavy hybrid stars

Complete plasmon spectrum of two-stream system

Effects of the interaction between the magnetic moments on the energy levels of a pionic atom

Light Quarks in the Screened Dyon-Anti-Dyon Coulomb Liquid Model II

Affiliations

Study of in-medium $η^{'}$ properties in the ( $γ$ , $η^{'} p$ ) reaction on nuclei