Nuclear Theory·nucl-th

Tuesday·June 19, 2018

11 papers—10 primary·1 cross-listed

01
Four-body eikonal approach to three-body halo nuclei scattering
L. A. Souza · E. V. Chimanski · T. Frederico · B. V. Carlson · M. S. Hussein
Halo nuclei projectiles can undergo into a fragmentation process when scattered by a nucleus target. The corresponding core from exotic nuclei is usually observed while the others fragments of the reaction are not. We use the recently proposed theory by [Phys. Lett. B767, 53 (2017)] with a four-body description of the inclusive breakup reaction where the projectile is 20C described like a two-neutron halo nucleus. The momentum of both neutrons are integrated out giving a generic description of the core angular distribution. In this preliminary study we perform an analysis of the inclusive inelastic breakup cross-section using the eikonal approximation for the distorted wave function of the projectile. A study of the inclusive inelastic cross-sections of 20C from the collision with different targets are presented.
nucl-th2 citations
02
Transverse Momentum Balance and Angular Distribution of $b b ˉ$ Dijets in Pb+Pb collisions
Wei Dai🇨🇳 · Sa Wang🇨🇳 · Shan-Liang Zhang🇨🇳 · Ben-Wei Zhang🇨🇳 · Enke Wang🇨🇳
The productions of inclusive b-jet and $b b ˉ$ dijets in Pb+Pb collisions have been investigated by considering the heavy quark and the light quark in-medium evolution simultaneously. The initial hard processes of inclusive b-jet and $b b ˉ$ dijets productions are described by a next-to-leading order (NLO) plus parton shower Monte Carlo (MC) event generator SHERPA which can be well-matched with the experimental data in p+p collisions. The framework combines the Langevin transport model to describe the evolution of the bottom quark also its collisional energy loss and the higher-twist description to consider the radiative energy loss of both the bottom and light quarks. We compare the theoretical simulation of inclusive jet and inclusive b-jet $R_{AA}$ in Pb+Pb collisions at $s_{NN} = 2.76$ TeV with the experimental data, and then present the theoretical simulation of the momentum balance of the $b b ˉ$ dijet in Pb+Pb collisions at $5.02$ TeV with the recent CMS data for the first time. A similar trend as that in inclusive dijets has been observed in $b b ˉ$ dijets, the production distribution is shifted to smaller $x_{J}$ due to the jet quenching effect. At last, the prediction of the normalized azimuthal angle distribution of the $b b ˉ$ dijet in Pb+Pb collisions at $5.02$ TeV has been reported. The medium induced energy loss effect of the $b b ˉ$ dijets will overall suppress its production, but the same side ( $Δ ϕ \to 0$ region) suffers more energy loss than away side ( $Δ ϕ \to π$ region), therefore lead to the suppression on the same side and the enhancement on the away side in the normalized azimuthal angle distribution in A+A collisions.
nucl-thhep-phnucl-exCPC(2020)·42 citations
03
Semiclassical trace formula for truncated spherical well potentials: Toward the analyses of shell structures in nuclear fission processes
Ken-ichiro Arita
Trace formulas for the contributions of degenerate periodic-orbit families to the semiclassical level density in truncated spherical hard-wall potentials are derived. In addition to the portion of the continuous periodic-orbit family contribution which persists after truncation, end-point corrections to the truncated family should be taken into account. I propose a formula to evaluate these end-point corrections as separate contributions of what I call marginal orbits. Applications to the two-dimensional billiard and three-dimensional cavity systems with the three-quadratic-surfaces shape parametrization, initiated to describe the nuclear fission processes, reveal unexpectedly large effects of the marginal orbits.
nucl-thnlin.CDPRC(2018)·5 citations
04
Modification of hyperon masses in nuclear matter
Ki-Hoon Hong🇰🇷 · Ulugbek Yakhshiev🇰🇷 · Hyun-Chul Kim🇰🇷
We discuss the properties of baryons within the framework of the in-medium modified SU(3) Skyrme model. The modification is performed by a minimal way, the medium functionals in the SU(2) sector being introduced. These functionals are then related to nuclear matter properties near the saturation point. The modifications in the SU(3) sector are performed with the additional changes of kaon properties in nuclear matter. The results show that the properties of baryons in the strange sector are sensitive to the in-medium modifications of the kaon properties. The consistency of the in-medium modifications of hadron properties in the present approach with other model approaches and phenomenological indications is also discussed.
nucl-thhep-phPRC(2019)·5 citations
05
Chiral geometry and rotational structure for $^{130}$ Cs in the projected shell model
F. Q. Chen · J. Meng · S. Q. Zhang
The projected shell model with configuration mixing for nuclear chirality is developed and applied to the observed rotational bands in the chiral nucleus $^{130}$ Cs. For the chiral bands, the energy spectra and electromagnetic transition probabilities are well reproduced. The chiral geometry illustrated in the $K pl o t$ and the $a z i t h u ma l pl o t$ is confirmed to be stable against the configuration mixing. The other rotational bands are also described in the same framework.
nucl-thPLB(2018)·31 citations
06
Isovector and isoscalar proton-neutron pairing in $N > Z$ nuclei
D. Negrea · P. Buganu · D. Gambacurta · N. Sandulescu
We propose a particle number conserving formalism for the treatment of isovector-isoscalar pairing in nuclei with $N > Z$ . The ground state of the pairing Hamiltonian is described by a quartet condensate to which is appended a pair condensate formed by the neutrons in excess. The quartets are built by two isovector pairs coupled to the total isospin $T = 0$ and two collective isoscalar proton-neutron pairs. To probe this ansatz for the ground state we performed calculations for $N > Z$ nuclei with the valence nucleons moving above the cores $^{16}$ O, $^{40}$ Ca and $^{100}$ Sn. The calculations are done with two pairing interactions, one state-independent and the other of zero range, which are supposed to scatter pairs in time-revered orbits. It is proven that the ground state correlation energies calculated within this approach are very close to the exact results provided by the diagonalization of the pairing Hamiltonian. Based on this formalism we have shown that moving away of N=Z line, both the isoscalar and the isovector proton-neutron pairing correlations remain significant and that they cannot be treated accurately by models based on a proton-neutron pair condensate.
nucl-thPRC(2018)·19 citations
07
Calculating reactions with use of no-core shell-model states
V.D. Efros
A scheme to compute reactions is described that uses the Slater determinants constructed of oscillator orbitals. Simple linear equations are suggested for this purpose and shown to be efficient in model examples. A universal method to evaluate the required matrix elements is given.
nucl-thphysics.comp-phPRC(2019)·8 citations
08
Rotating solutions of nonideal transverse Chern-Simons magnetohydrodynamics and the anomalous Hall current
N. Sadooghi🇮🇷 · M. Shokri🇮🇷
In order to gain deeper insight into the physics of the novel rotating solution of nonideal transverse magnetohydrodynamics (MHD), presented in one of our recent works, we replace the previously considered Maxwell theory with the $C P$ violating Maxwell-Chern-Simons (MCS) theory. In this way, dissipationless chiral magnetic (CM) and anomalous Hall (AH) currents appear in the MCS equation of motion, that, together with equations of relativistic hydrodynamics, builds the set of constitutive equations of the nonideal transverse Chern-Simons magnetohydrodynamics (CSMHD). We are, in particular, interested in the effect of these currents on the evolution of electromagnetic fields in a uniformly and longitudinally expanding quark-gluon plasma with chirality imbalance. Combining the constitutive equations of CSMHD under these assumptions, we arrive, as expected, at two distinct rotating and nonrotating solutions for electromagnetic fields. The rotation occurs with increasing rapidity and a constant angular velocity $ω_{0}$ . Remarkably, the relative angle between the electric and magnetic fields, $δ$ , turns out to be given by the coefficient of AH current $κ_{E}$ and the electric conductivity of the medium $σ$ , as $δ = tan^{- 1} (κ_{E} / σ)$ . Whereas the nonrotating solution implies the AH coefficient to be vanishing, and thus nonrotating electric and magnetic fields to be either parallel or antiparallel, the relative orientation of rotating electric and magnetic fields and the evolution of the CM conductivity $κ_{B}$ are strongly affected by nonvanishing $κ_{E}$ . We explore the effect of positive and negative $ω_{0}$ on the evolution of the CM current, and show, in particular, that a rotation of electromagnetic fields with negative $ω_{0}$ implies a sign flip of the CM current in a chiral fluid with nonvanishing AH current.
nucl-thcond-mat.str-elhep-phhep-thPRD(2018)·6 citations
09
Dilepton photoproduction measures the fluctuations of initial electromagnetic fields in nuclear collisions
Guansong Li · Kai Zhou🇩🇪 · Baoyi Chen
Dilepton production from two photon interactions $γ γ \to l^{+} l^{-}$ are studied in semi-central and peripheral nuclear collisions. Based on Weizsäcker-Williams approach, it is shown that the dilepton photoproduction is proportional to the electromagnetic (EM) fields $\sim E^{2} B^{2}$ and therefore sensitive to the magnitude and lifetime of initial EM fields which last only for a short time and are hard to be measured in experiments directly. We propose dilepton photoproduction as a probe for the nuclear charge fluctuations, which are crucial for the electric/magnetic field induced chiral and charge particle evolutions. We calculate the relative standard deviation of dilepton mass spectrum with event-by-event fluctuating nuclear charge distributions (and EM fields).
nucl-thhep-phCommun.Theor.Phys.(2020)·3 citations
10
A new and finite family of solutions of hydrodynamics. Part I: Fits to pseudorapidity distributions
T. Csorgo🇭🇺 · G. Kasza · M. Csanad🇭🇺 · Z. F. Jiang🇨🇳
We highlight some of the interesting properties of a new and finite, exact family of solutions of 1 + 1 dimensional perfect fluid relativistic hydrodynamics. After reviewing the main properties of this family of solutions, we present the formulas that connect it to the measured rapidity and pseudo-rapidity densities and illustrate the results with fits to p+p collisions at 8 TeV and Pb+Pb collisions at $s_{N N} = 5.02$ TeV.
nucl-thhep-exhep-phnucl-exActa Phys.Polon.B(2019)·9 citations
11
Weyl systems: anomalous transport normally explained
K. Morawetz
The chiral kinetic theory is derived from exact spinor mean field equations without symmetry-breaking terms for large classes of SU(2) systems with spin-orbit coupling. The influence of the Wigner function's off-diagonal elements is worked out. The decoupling of the diagonal elements renormalizes the drift according to Berry connection which is found as an expression of the meanfield, spin-orbit coupling and magnetic field. As special limit, Weyl systems are considered. The anomalous term $\sim \V E \V B$ in the balance of the chiral density appears consequently by an underlying conserving theory. The experimental observations of this term and the anomalous magneto-transport in solid-sate physics usually described by chiral kinetic theory are therefore not a unique signal for mixed axial-gravitational or triangle anomaly and no signal for the breaking of Lorentz-invariance. The source of the anomalous term is by two thirds the divergence of Berry curvature at zero momentum which can be seen as Dirac monopole and by one third the Dirac sea at infinite momentum. During the derivation of the chiral kinetic theory this source by the Dirac sea is transferred exclusively to the Dirac monopole due to the projection of the spinor Wigner functions to the chiral basis. The dynamical result is shown to suppress the anomalous term by two thirds.
↳ cond-mat.str-elcond-mat.othernucl-thphysics.plasm-ph+1Eur.Phys.J.B(2019)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE