Nuclear Theory·nucl-th

Thursday·November 10, 2016

11 papers—9 primary·2 cross-listed

01
Electromagnetic and transport properties of QGP within PLSM approach
Abdel Nasser Tawfik (Egyptian Ctr. Theor. Phys., Cairo, WLCAPP, Cairo)🇪🇬
In order to study the response of the quantum chromodynamic matter to finite electromagnetic fields, we utilize the Polyakov linear - sigma model (PLSM) in mean-field approximation. Due to participants' momentum imbalance and off-center relativistic motion of the spectators' electric charges, localized, short-lived, huge electromagnetic fields are to be generated in the relativistic heavy-ion collisions. We report on various electromagnetic and transport properties of the new-state-of matter; the quark-gluon plasma (QGP) within the QCD-like approach, PLSM. We find an excellent agreement between our PLSM calculations and various recent lattice QCD simulations and notice that the magnetization and the magnetic susceptibility and the relative permeability obviously increase in the QGP phase. We predict that increasing the magnetic field remarkable decreases the viscosity, especially in hadron phase. while in QGP phase, the viscous properties seem not being affected with.
nucl-thhep-thPoS(2017)·1 citation
02
SU( $4$ ) Polyakov linear-sigma model at finite temperature and density
Abdel Magied Diab (Egyptian Ctr. Theor. Phys., Cairo, WLCAPP, Cairo)🇪🇬 · Azar I. Ahmadov (Baku State U.)🇦🇿 · Abdel Nasser Tawfik (Egyptian Ctr. Theor. Phys., Cairo, WLCAPP, Cairo)🇪🇬 · Eiman Abou El Dahab (WLCAPP, Cairo and MTI U., Cairo)🇪🇬
In mean-field approximation, the SU( $4$ ) Polyakov linear - sigma model (PLSM) is constructed in order to characterize the quark-hadron phase structure in a wide range of temperatures and densities. The chiral condensates $σ_{l}$ , $σ_{s}$ and $σ_{c}$ for light, strange and charm quarks, respectively, and the deconfinement order-parameters $ϕ$ and $ϕ^{*}$ shall be analyzed at finite temperatures and densities. We conclude that the critical temperatures corresponding to charm condensates are greater than that to strange and light ones, respectively. Thus, the charm condensates are likely not affected by the QCD phase transition. Furthermore, increasing the chemical potentials decreases the corresponding critical temperatures.
nucl-thhep-thPoS(2016)·7 citations
03
The effect of inclusion of $Δ$ resonances in relativistic mean-field model with scaled hadron masses and coupling constants
K. A. Maslov🇷🇺 · E. E. Kolomeitsev🇸🇰 · D. N. Voskresensky🇷🇺
Knowledge of the equation of state of the baryon matter plays a decisive role in the description of neutron stars. With an increase of the baryon density the filling of Fermi seas of hyperons and $Δ$ isobars becomes possible. Their inclusion into standard relativistic mean-field models results in a strong softening of the equation of state and a lowering of the maximum neutron star mass below the measured values. We extend a relativistic mean-field model with scaled hadron masses and coupling constants developed in our previous works and take into account now not only hyperons but also the $Δ$ isobars. We analyze available empirical information to put constraints on coupling constants of $Δ$ s to mesonic mean fields. We show that the resulting equation of state satisfies majority of presently known experimental constraints.
nucl-thastro-ph.HEhep-phJ.Phys.Conf.Ser.(2017)·7 citations
04
Flavour decomposition of electromagnetic transition form factors of nucleon resonances
Jorge Segovia🇩🇪 · Craig D. Roberts🇺🇸
In Poincaré-covariant continuum treatments of the three valence-quark bound-state problem, the force behind dynamical chiral symmetry breaking also generates nonpointlike, interacting diquark correlations in the nucleon and its resonances. We detail the impact of these correlations on the nucleon's elastic and nucleon-to-Roper transition electromagnetic form factors, providing flavour-separation versions that can be tested at modern facilities.
nucl-thhep-lathep-phEPJ Web Conf.(2017)·0 citations
05
Inner crust of neutron stars with mass-fitted Skyrme interaction
K. Madhuri🇮🇳 · D. N. Basu🇮🇳 · T. R. Routray🇮🇳 · S. P. Pattnaik🇮🇳
The mass, radius and crustal fraction of moment of inertia in neutron stars are calculated using $β$ -equilibrated nuclear matter obtained from Skyrme effective interaction. The transition density, pressure and proton fraction at the inner edge separating the liquid core from the solid crust of the neutron stars are determined from the thermodynamic stability conditions using the KDE0v1 set. The neutron star masses obtained by solving the Tolman-Oppenheimer-Volkoff equations using neutron star matter obtained from this set is able to describe highly massive compact stars $\sim$ 2 $M_{⊙}$ . The crustal fraction of the moment of inertia can be extracted from studying pulsar glitches. This fraction is highly dependent on the core-crust transition pressure and corresponding density. These results for pressure and density at core-crust transition together with the observed minimum crustal fraction of the total moment of inertia provide a limit for the radius of the Vela pulsar: $R \geq$ 3.69+3.44 M/ $M_{⊙}$ . Present calculations suggest that the crustal fraction of the total moment of inertia can be at most 3.6% due to crustal entrainment caused by Bragg reflection of unbound neutrons by lattice ions.
nucl-thEPJA(2017)·5 citations
06
Gamma-rays from $^{na t}$ Sn and $^{na t}$ C induced by fast neutrons
Igor Kadenko · Vladimir Plujko · Borys Bondar · Oleksandr Gorbachenko · Borys Leshchenko · Kateryna Solodovnyk
The cross-sections of prompt gamma-ray production from $^{na t}$ Sn and $^{na t}$ C elements induced by 14.1-MeV neutrons were measured. The time-of-flight technique was used for n-gamma discrimination. The experimental results were compared with theoretical calculations performed by Empire 3.2 and Talys 1.6 codes using different models for photon strength function and nuclear level density.
nucl-th1 citation
07
Event-by-event $v_{n}$ correlations of soft hadrons and heavy mesons in heavy ion collisions
Caio A. G. Prado · Jacquelyn Noronha-Hostler · Roland Katz · Alexandre A. P. Suaide · Jorge Noronha · Marcelo G. Munhoz
In this paper heavy quark energy loss models are embedded in full event-by-event viscous hydrodynamic simulations to investigate the nuclear suppression factor and azimuthal anisotropy of D $^{0}$ mesons in PbPb collisions at 5.02 TeV in the $p_{T}$ range 8-40 GeV. In our model calculations, the $R_{AA}$ of D $^{0}$ mesons is consistent with experimental data from the CMS experiment. We present the first calculations of heavy flavor cumulants $v_{2} {2}$ and $v_{3} {2}$ (and also discuss $v_{2} {4}$ ), which is also consistent with experimental data. Event-shape engineering techniques are used to compute the event-by-event correlation between the soft hadron $v_{n}$ and the heavy meson $v_{n}$ . We predict a linear correlation between these observables on an event-by-event basis.
nucl-thhep-exhep-phPRC(2017)·75 citations
08
Production of charmed baryons in $p ˉ p$ collisions close to their thresholds
J. Haidenbauer🇩🇪 · G. Krein🇧🇷
Cross sections for the charm-production reactions $p ˉ p \to Λ ˉ_{c}^{-} Σ_{c}^{+}$ , $Σ ˉ_{c} Σ_{c}$ , $Ξ ˉ_{c} Ξ_{c}$ , and $Ξ ˉ_{c}^{'} Ξ_{c}^{'}$ are presented, for energies near their respective thresholds. The results are based on a calculation performed in the meson-exchange framework in close analogy to earlier studies of the Jülich group on the strangeness-production reactions $p ˉ p \to Λ ˉ Σ$ , $Σ ˉ Σ$ , $Ξ ˉ Ξ$ by connecting the two sectors via SU(4) flavor symmetry. The cross sections are found to be in the order of $0.1 - 1$ $μ b$ at energies of $100$ MeV above the respective thresholds, for all considered channels. Complementary to meson-exchange, where the charmed baryons are produced by the exchange of $D$ and $D^{*}$ mesons, a charm-production potential derived in a quark model is employed for assessing uncertainties. The cross sections predicted within that picture turned out to be significantly smaller.
nucl-thhep-phPRD(2017)·15 citations
09
Comparative effect of an addition of a surface term to the Woods-Saxon potential on the thermodynamics of a nucleon
B. C. Lütfüoğlu
In this study, we reveal the difference between Woods-Saxon (WS) and Generalized Symmetric Woods-Saxon (GSWS) potentials in order to describe the physical properties of a nucleon, by means of solving Schrödinger eq. for the two potentials. The additional term squeezes the WS potential well, which leads an upward shift in the spectrum, resulting in a more realistic picture. The resulting GSWS potential does not merely accommodate extra quasi bound states, but also has modified bound state spectrum. As an application, we apply the formalism to a real problem, an $α$ particle confined in Bohrium- $270$ nucleus. The thermodynamic functions Helmholtz energy, entropy, internal energy, specific heat of the system are calculated and compared for both wells. The internal energy and the specific heat capacity increase as a result of upward shift in the spectrum. The shift of the Helmholtz free energy is a direct consequence of the shift of the spectrum. The entropy decreases because of a decrement in the number of available states.
nucl-thCommun.Theor.Phys.(2018)·9 citations
10
Tetra-Quark Interpretation of X(3872) and Z_c(3900) Revisited
Kunihiko Terasaki🇯🇵
In relation to the newly observed bottom-strange X^{+,-}(5568) mesons, we revisit our tetra-quark interpretation of X(3872) and Z_c(3900). It is discussed that our assignment of X^{+,-}(5568) to charged components of iso-triplet bottom partners of D_{s0}^+(2317) is compatible with the revised version of our tetra-quark interpretation of X(3872) and Z_c(3900).
↳ hep-phnucl-th2 citations
11
Analytical On-shell Calculation of Higher Order Scattering: Massless Particles
Barry R. Holstein🇺🇸
We demonstrate that the use of on-shell methods involving calculation of the discontinuity across the t-channel cut associated with the exchange of a pair of massless particles can be used to evaluate loop contributions to the electromagnetic and gravitational scattering of both massive and massless particles. In the gravitational case the use of factorization permits a straightforward and algebraic calculation of higher order scattering results, which were obtained previously by considerably more arduous Feynman diagram techniques.
↳ hep-phgr-qchep-thnucl-th4 citations

Affiliations

first authorsco-authorsvia INSPIRE