Nuclear Theory·nucl-th

Tuesday·August 17, 2021

10 papers—4 primary·6 cross-listed

01
[Submitted on 14 Aug 2021]
Systematic investigation of the high-spin structures in the odd-odd nuclei $^{166, 168, 170, 172}$ Re by a particle-number conserving method
Zhen-Hua Zhang · Shuo-Yi Liu
The recently observed two and four-quasiparticle high-spin rotational bands in the odd-odd nuclei $^{166, 168, 170, 172}$ Re are investigated using the cranked shell model with pairing correlations treated by a particle-number conserving method. The experimental moments of inertia and alignments can be reproduced well by the present calculation if appropriate bandhead spins and configurations are assigned for these bands, which in turn confirms their spin and configuration assignments. It is found that the bandhead spins of those two rotational bands observed in $^{166}$ Re~[Li {\it et al.}, Phys. Rev. C 92 014310 (2015)] should be both increased by $2ℏ$ to get in consistent with the systematics of the experimental and calculated moments of inertia for the same configurations in $^{168, 170, 172}$ Re. The variations of the backbendings/upbendings with increasing neutron number in these nuclei are investigated. The level crossing mechanism is well understood by analysing the variations of the occupation probabilities of the single-particle states close to the Fermi surface and their contributions to the angular momentum alignment with rotational frequency. In addition, the influence of the deformation driving effects of the proton $1/ 2^{-} [541]$ ( $h_{9/2}$ ) orbtial on the level crossing in $^{172}$ Re is also discussed.
Comments:
29 pages, 14 figures, 3 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2108.06501 [pdf]
NPA(2021)·0 citations
02
[Submitted on 15 Aug 2021]
Nuclei with up to $A = 6$ nucleons with artificial neural network wave functions
Alex Gnech🇺🇸 · Corey Adams🇺🇸 · Nicholas Brawand🇺🇸 · Giuseppe Carleo🇨🇭 · Alessandro Lovato🇺🇸 · Noemi Rocco🇺🇸
The ground-breaking works of Weinberg have opened the way to calculations of atomic nuclei that are based on systematically improvable Hamiltonians. Solving the associated many-body Schrödinger equation involves non-trivial difficulties, due to the non-perturbative nature and strong spin-isospin dependence of nuclear interactions. Artificial neural networks have proven to be able to compactly represent the wave functions of nuclei with up to $A = 4$ nucleons. In this work, we extend this approach to $^{6}$ Li and $^{6}$ He nuclei, using as input a leading-order pionless effective field theory Hamiltonian. We successfully benchmark their binding energies, point-nucleon densities, and radii with the highly accurate hyperspherical harmonics method.
Comments:
15 pages, 3 figures, invited contribution to the special issue in Few-Body Systems "Celebrating 30 years of Steven Weinberg's papers on Nuclear Forces from Chiral Lagrangians"
Subjects:
Nuclear Theory (nucl-th); cond-mat.dis-nn (cond-mat.dis-nn); Quantum Physics (quant-ph)
arXiv:
2108.06836 [pdf]
Few Body Syst.(2022)·47 citations
03
[Submitted on 16 Aug 2021]
Connecting Theory to Heavy Ion Experiment
Gaoqing Cao🇨🇳 · Iurii Karpenko🇨🇿
Only a fraction of all $Λ$ and $Λ ˉ$ hyperons detected in heavy ion collisions are produced from the hot and dense matter directly at the hadronization. These hyperons are called the {\em primary} hyperons. The rest of the hyperons are products of the decays of heavier hyperon states, which in turn are produced at the hadronization. As such, the polarization of only primary hyperons can be described with the formulae introduced in Sect. 8. For the rest of the hyperons, the polarization transfer in the decays has to be computed, and convoluted with the polarization of the mother hyperon. In this chapter, a derivation of the polarization transfer coefficients, as well as the computation of the mean polarization of all $Λ$ hyperons detected in the experiment, is presented. The chapter is concluded with the calculation of the resonance contributions to the global and local $Λ$ polarizations.
Comments:
Section 10 in the book "Strongly interacting matter under rotation"
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2108.06904 [pdf]
Lect.Notes Phys.(2021)·1 citation
04
[Submitted on 16 Aug 2021]
Dynamics of in-medium quarkonia in SU(3) and SU(2) gauge theories
Yukinao Akamatsu🇯🇵 · Masayuki Asakawa🇯🇵 · Shiori Kajimoto🇯🇵
Decoherence dynamics of quarkonia is studied in the high-temperature deconfined phase of SU( $N_{c}$ ) gauge theories. In particular, we analyze the symmetry properties of SU( $N_{c}$ ) stochastic potential model and find a novel "event-by-event" symmetry for $N_{c} = 2$ case, similar to the $G$ -parity of hadronic systems. This novel symmetry constrains the relation between diagonal and off-diagonal components of quarkonium density matrix, leaving the latter to be finite at late times. We also present one-dimensional numerical simulation of the model, which indicates the usefulness of the complex potential simulations for the quarkonium survival probabilities in relativistic heavy-ion collisions, provided that the effect of dissipation can be neglected.
Comments:
17 pages, 7 figures, 10 MB; v2: typos fixed, figures corrected with proper units, and references added
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Quantum Physics (quant-ph)
arXiv:
2108.06921 [pdf]
PRD(2022)·15 citations
05
[Submitted on 13 Aug 2021] (cross-list from hep-ph)
Dijet impact factor in DIS at next-to-leading order in the Color Glass Condensate
Paul Caucal🇺🇸 · Farid Salazar🇺🇸 · Raju Venugopalan🇺🇸
We compute the next-to-leading order impact factor for inclusive dijet production in deeply inelastic electron-nucleus scattering at small $x_{Bj}$ . Our computation, performed in the framework of the Color Glass Condensate effective field theory, includes all real and virtual contributions in the gluon shock wave background of all-twist lightlike Wilson line correlators. We demonstrate explicitly that the rapidity evolution of these correlators, to leading logarithmic accuracy, is described by the JIMWLK Hamiltonian. When combined with the next-to-leading order JIMWLK Hamiltonian, our results for the impact factor improve the accuracy of the inclusive dijet cross section to $O (α_{s}^{2} ln (x_{f} / x_{Bj}))$ , where $x_{f}$ is a rapidity factorization scale. These results are an essential ingredient in assessing the discovery potential of inclusive dijets to uncover the physics of gluon saturation at the Electron-Ion Collider.
Comments:
v3: typos corrected post-publication, a list of these will be published separately as an Erratum. v2: matches the published version. v1: 112 pages, 11 figures, 4 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2108.06347 [pdf]
JHEP(2021)·106 citations
06
[Submitted on 13 Aug 2021] (cross-list from hep-ph)
Chiral Symmetry Breaking and Confinement from an Interacting Ensemble of Instanton-dyons in Two-flavor Massless QCD
Dallas DeMartini🇺🇸 · Edward Shuryak🇺🇸
In this work we present the results from numerical simulations of an interacting ensemble of instanton-dyons in the $S U (3)$ gauge group with $N_{f} = 2$ flavors of massless quarks. Dynamical quarks are included via the effective interactions induced by the fermionic determinant evaluated in the subspace of topological zero modes. The eigenvalue spectrum of the Dirac operator is studied at different volumes to extract the chiral condensate and eigenvalue gap, with both observables providing consistent values of the chiral transition temperature $T_{c}$ . We find that a sufficient density of dyons is responsible for generating the confining potential and breaking the chiral symmetry, both of which are compatible with second-order transitions.
Comments:
13 pages, 10 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2108.06353 [pdf]
PRD(2021)·12 citations
07
[Submitted on 15 Aug 2021] (cross-list from hep-ph)
Scaling behaviors of heavy flavor meson suppression and flow in different nuclear collision systems at the LHC
Shu-Qing Li🇨🇳 · Wen-Jing Xing🇨🇳 · Xiang-Yu Wu🇨🇳 · Shanshan Cao🇨🇳 · Guang-You Qin🇨🇳
We explore the system size dependence of heavy-quark-QGP interaction by studying the heavy flavor meson suppression and elliptic flow in Pb-Pb, Xe-Xe, Ar-Ar and O-O collisions at the LHC. The space-time evolution of the QGP is simulated using a (3+1)-dimensional viscous hydrodynamic model, while the heavy-quark-QGP interaction is described by an improved Langevin approach that includes both collisional and radiative energy loss inside a thermal medium. Within this framework, we provides a reasonable description of the $D$ meson suppression and flow coefficients in Pb-Pb collisions, as well as predictions for both $D$ and $B$ meson observables in other collision systems yet to be measured. We find a clear hierarchy for the heavy meson suppression with respect to the size of the colliding nuclei, while their elliptic flow coefficient relies on both the system size and the geometric anisotropy of the QGP. Sizable suppression and flow are predicted for both $D$ and $B$ mesons in O-O collisions, which serve as a crucial bridge of jet quenching between large and small collision systems. Scaling behaviors between different collision systems are shown for heavy meson suppression factor and the bulk-eccentricity-rescaled heavy meson elliptic flow as functions of the number of participant nucleons in heavy-ion collisions.
Comments:
10 pages, 9 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2108.06648 [pdf]
EPJC(2021)·28 citations
08
[Submitted on 15 Aug 2021] (cross-list from hep-ph)
Electromagnetic response of hot QCD medium in the presence of background time-varying fields
Gowthama K K🇮🇳 · Manu Kurian🇮🇳 · Vinod Chandra🇮🇳
The response of the hot QCD medium in the presence of external time dependent electromagnetic fields has been studied within the relativistic Boltzmann transport theory. The impact of the time dependence of the electromagnetic fields and collisional aspects of the medium to the induced electric and Hall current densities has been explored. The non-equilibrium momentum distribution of degrees of freedom has been obtained in the presence of space-time varying electromagnetic fields. Further, the analysis has been extended to an anisotropic QCD medium while incorporating the in-medium interaction effects. It is observed that the electric charge transport is sensitive to the inhomogeneity of the fields and the momentum anisotropy of the QCD medium.
Comments:
8 pages, 2 figures, two-column
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2108.06791 [pdf]
PRD(2021)·19 citations
09
[Submitted on 16 Aug 2021] (cross-list from hep-ph)
Holographic charm and bottom pentaquarks II: Open and hidden decay widths
Yizhuang Liu🇵🇱 · Maciej A. Nowak🇵🇱 · Ismail Zahed🇺🇸
We analyze the decay modes of the three $[\frac{1}{2} \frac{1}{2}^{-}]_{S = 0, 1}$ and $[\frac{1}{2} \frac{3}{2}^{-}]_{S = 1}$ non-strange pentaquarks with hidden charm and bottom, predicted by holographic QCD in the heavy quark limit. In leading order, the pentaquarks %are composed of heavy-light mesons in bulk bound to an instanton core. They are degenerate and stable by heavy quark symmetry. At next to leading order, the spin interactions lift the degeneracy and cause the pentaquarks to decay. We show that the open charm (bottom) decay modes dwarf the hidden charm (bottom) ones, with total widths that are consistent with those recently reported by LHCb for charm pentaquarks. Predictions for bottom pentaquarks are given.
Comments:
26 pages, 1 figure
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2108.07074 [pdf]
PRD(2021)·16 citations
10
[Submitted on 16 Aug 2021] (cross-list from hep-ph)
Resummation of the Sivers asymmetry in heavy flavor dijet production at the Electron-Ion Collider
Zhong-Bo Kang🇺🇸 · Jared Reiten🇺🇸 · Ding Yu Shao🇨🇳 · John Terry🇺🇸
We review our transverse momentum dependent factorization and resummation formalism for heavy flavor dijet production at the EIC. In this formalism, we have calculated the heavy flavor mass corrections in the collinear-soft and jet functions, and in the resummed expression for the cross section. By establishing this formalism, we then study the effects of the mass corrections by providing predictions at the EIC for the massive case and for the case where the mass is neglected. We find that the heavy flavor mass effects can give sizable corrections to the predicted asymmetry.
Comments:
Submission to SciPost
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2108.07257 [pdf]
SciPost Phys.Proc.(2022)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE