Nuclear Theory·nucl-th

Friday·May 25, 2018

9 papers—2 primary·7 cross-listed

01
The Role of Tensor Force in Heavy-Ion Fusion Dynamics
Lu Guo · Cedric Simenel · Long Shi · Chong Yu
The tensor force is implemented into the time-dependent Hartree-Fock (TDHF) theory so that both exotic and stable collision partners, as well as their dynamics in heavy-ion fusion, can be described microscopically. The role of tensor force on fusion dynamics is systematically investigated for $^{40} Ca +^{40} Ca$ , $^{40} Ca +^{48} Ca$ , $^{48} Ca +^{48} Ca$ , $^{48} Ca +^{56} Ni$ , and $^{56} Ni +^{56} Ni$ reactions which vary by the total number of spin-unsaturated magic numbers in target and projectile. A notable effect on fusion barriers and cross sections is observed by the inclusion of tensor force. The origin of this effect is analyzed. The influence of isoscalar and isovector tensor terms is investigated with the T $I J$ forces. These effects of tensor force in fusion dynamics are essentially attributed to the shift of low-lying vibration states of colliding partners and nucleon transfer in the asymmetric reactions. Our calculations of above-barrier fusion cross sections also show that tensor force does not significantly affect the dynamical dissipation at near-barrier energies.
nucl-thnucl-exPLB(2018)·54 citations
02
The cathode tube effect: heavy quarks probing the Glasma in p-Pb collisions
Marco Ruggieri🇨🇳 · Santosh K. Das🇨🇳
We study the propagation of charm quarks in the early stage of high energy proton-lead collision, considering the interaction of these quarks with the evolving Glasma by means of the Wong equations. Neglecting quantum fluctuations at the initial time the Glasma is made of longitudinal fields, but the dynamics leads to a quick formation of transverse fields; we estimate such a formation time as $Δ t \approx 0.1$ fm/c which is of the same order of the formation time of heavy quark pairs $t_{formation} \approx 1/ (2 m)$ . Limiting ourselves to the simple case of a static longitudinal geometry, we find that heavy quarks are accelerated by the strong transverse color fields in the early stage and this leads to a tilting of the $c -$ quarks spectrum towards higher $p_{T}$ states. This average acceleration can be understood in terms of drag and diffusion of $c -$ quarks in a hot medium and appears to be similar to the one felt by the electrons ejected by the electron cannon in a cathode tube: we dub this effect as {\it cathode tube effect}. The tilting of the spectrum affects the nuclear modification factor, $R_{pPb}$ , suppressing this below one at low $p_{T}$ and making it larger than one at intermediate $p_{T}$ . We compute $R_{pPb} (p_{T})$ after the evolution of charm quarks in the gluon fields and we find that its shape is in qualitative agreement with the measurements of the same quantity for $D -$ mesons in proton-lead collisions.
nucl-thhep-phnucl-exPRD(2018)·55 citations
03
Tunable $χ / P T$ Symmetry in Noisy Graphene
E. Frade Silva · A. L. R. Barbosa · M. S. Hussein · J. G. G. S. Ramos
We investigate the resonant regime of a mesoscopic cavity made of graphene or a doped beam splitter. Using Non-Hermitian Quantum Mechanics, we consider the Bender-Boettcher assumption that a system must obey parity and time reversal symmetry. Therefore, we describe such system by coupling chirality, parity and time reversal symmetries through the scattering matrix formalism and apply it in the shot noise functions, also derived here. Finally we show how to achieve the resonant regime only by setting properly the parameters concerning the chirality and the PT symmetry.
↳ cond-mat.mes-hallnucl-thquant-ph0 citations
04
Lectures on non-equilibrium effective field theories and fluctuating hydrodynamics
Paolo Glorioso🇺🇸 · Hong Liu🇺🇸
We review recent progress in developing effective field theories (EFTs) for non-equilibrium processes at finite temperature, including a new formulation of fluctuating hydrodynamics, and a new proof of the second law of thermodynamics. There are a number of new elements in formulating EFTs for such systems. Firstly, the nature of IR variables is very different from those of a system in equilibrium or near the vacuum. Secondly, while all static properties of an equilibrium system can in principle be extracted from the partition function, there appears no such quantity which can capture all non-equilibrium properties. Thirdly, non-equilibrium processes often involve dissipation, which is notoriously difficult to deal with using an action principle. The purpose of the review is to explain how to address these issues in a pedagogic manner, with fluctuating hydrodynamics as a main example.
↳ hep-thcond-mat.stat-mechgr-qcnucl-thPoS(2018)·266 citations
05
Hierarchy of azimuthal anisotropy harmonics in collisions of small systems from the Color Glass Condensate
Mark Mace🇺🇸 · Vladimir V. Skokov🇺🇸 · Prithwish Tribedy🇺🇸 · Raju Venugopalan🇺🇸
We demonstrate that the striking systematics of two-particle azimuthal Fourier harmonics $v_{2}$ and $v_{3}$ in ultrarelativistic collisions of protons, deuterons and helium-3 ions off gold nuclei measured by the PHENIX Collaboration [arXiv:1805.02973] at the Relativistic Heavy Ion Collider (RHIC) is reproduced in the Color Glass Condensate (CGC) effective field theory. This contradicts the claim in [arXiv:1805.02973] that their data rules out initial state based explanations. The underlying systematics of the effect, as discussed previously in [arXiv:1705.00745,arXiv:1706.06260,arXiv:1801.09704], arise from the differing structure of strong color correlations between gluon domains of size $1/ Q_{S}$ at fine ( $p_{⊥} ⪆ Q_{S}$ ) or coarser ( $p_{⊥} ⪅ Q_{S}$ ) transverse momentum resolution. Further tests of the limits of validity of this framework can be carried out in light-heavy ion collisions at both RHIC and the Large Hadron Collider. Such measurements also offer novel opportunities for further exploration of the role of the surprisingly large short-range nuclear correlations measured at Jefferson Lab.
↳ hep-phnucl-exnucl-thPRL(2018)·113 citations
06
Properties of Massive Rotating Protoneutron Stars with Hyperons: Structure and Universality
Smruti Smita Lenka🇮🇳 · Prasanta Char🇮🇳 · Sarmistha Banik🇮🇳
In this work, we study the properties and structure of a massive and rapidly rotating protoneutron star (PNS) with hyperon content. We follow several stages of quasi-stationary evolution in an approximate way at four discrete steps. We use a density-dependent (DD) relativistic mean field theory (RMF) model and calculate different quantities such as mass, equatorial radius, moment of inertia, and quadrupole moment to get different rotating configurations upto the mass-shedding limit. We study the effect of the appearance of $Λ$ , the lightest of all hyperons, on each of the evolutionary stages of the PNS. We also check its sensitivity to the inclusion of $ϕ$ vector meson as a mediator of $Λ - Λ$ interaction in detail. Finally, we investigate the universal relations between moment of inertia and compactness in the context of a hot and young compact object.
↳ astro-ph.HEastro-ph.SRnucl-thJ.Phys.G(2019)·27 citations
07
Magnetic moments of the spin- $\frac{3}{2}$ singly heavy baryons
Lu Meng🇨🇳 · Guang-Juan Wang🇨🇳 · Chang-Zhi Leng🇨🇳 · Zhan-Wei Liu🇨🇳 · Shi-Lin Zhu🇨🇳
We calculate the magnetic moments of spin- $\frac{3}{2}$ singly charmed baryons in the heavy baryon chiral perturbation theory (HBChPT). The analytical expressions are given up to $O (p^{3})$ . The heavy quark symmetry is used to reduce the number of low energy constants (LECs). With the lattice QCD simulation data as the magnetic moments of the charmed baryons, the numerical results are given up to $O (p^{3})$ in three scenarios. In the first scenario, we use the results in the quark model as the leading order input. In the second scenario, we use the heavy quark symmetry and neglect the contribution of heavy quark. In the third scenario, the heavy quark contribution is considered on the basis of the scenario II and the magnetic moments of singly bottom baryons are given as a by-product.
↳ hep-phhep-exhep-latnucl-thPRD(2018)·24 citations
08
Correlational latent heat by nonlocal quantum kinetic theory
K. Morawetz
The kinetic equation of nonlocal and non-instantaneous character unifies the achievements of the transport in dense quantum gases with the Landau theory of quasiclassical transport in Fermi systems. Large cancellations in the off-shell motion appear which are hidden usually in non-Markovian behaviors. The remaining corrections are expressed in terms of shifts in space and time that characterize the non-locality of the scattering process. In this way quantum transport is possible to recast into a quasi-classical picture. The balance equations for the density, momentum, energy and entropy include besides quasiparticle also the correlated two-particle contributions beyond the Landau theory. The medium effects on binary collisions are shown to mediate the latent heat, i.e., an energy conversion between correlation and thermal energy. For Maxwellian particles with time-dependent s-wave scattering, the correlated parts of the observables are calculated and a sign change of the latent heat is reported at a universal ratio of scattering length to the thermal De Broglie wavelength. This is interpreted as a change from correlational heating to cooling.
↳ cond-mat.str-elnucl-thquant-phPRB(2018)·5 citations
09
Quarkonium radiative decays from the hadronic Paschen-Back effect
Sachio Iwasaki🇯🇵 · Kei Suzuki🇯🇵
We study the radiative (E1 and M1) decays of P-wave quarkonia in a strong magnetic field based on the Lagrangian of potential nonrelativistic QCD. To investigate their properties, we implement a polarized wave function basis justified in the Paschen-Back limit. In a magnetic field stronger than the spin-orbit coupling, the wave functions of the P-wave quarkonia are drastically deformed by the Hadronic Paschen-Back effect. Such deformation leads to the anisotropy of the direction of decays from the P-wave quarkonia. The analytic formulas for the radiative decay widths in the nonrelativistic limit are shown, and the qualitative decay properties are discussed.
↳ hep-phhep-exnucl-exnucl-thPRD(2018)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE