Nuclear Theory·nucl-th

Friday·February 28, 2020

11 papers—5 primary·6 cross-listed

01
[Submitted on 26 Feb 2020]
Local spin polarizations in relativistic heavy ion collisions
Shuai Y. F. Liu🇨🇳 · Yifeng Sun🇮🇹 · Che Ming Ko🇺🇸
Based on a generalized side-jump formalism for massless chiral fermions, which naturally takes into account the spin-orbit coupling in the scattering of two chiral fermions and the chiral vortical effect in a rotating chiral fermion matter, we have developed a covariant and total angular momentum conserved chiral transport model to study both the global and local polarizations of this matter. For a system of massless quarks of random spin orientations and finite vorticity in a box, we have demonstrated that the model can exactly conserve the total angular momentum of the system and dynamically generate the quark spin polarization expected from a thermally equilibrated quark matter. Using this model to study the spin polarization in relativistic heavy-ion collision, we have found that the local quark spin polarizations depend strongly on the reference frame where they are evaluated as a result of the nontrivial axial charge distribution caused by the chiral vortical effect. We have further shown that because of the anomalous orbital or side-jump contribution to the quark spin polarization, the local quark polarizations calculated in the medium rest frame are qualitatively consistent with the local polarizations of Lambda hyperons measured in experiments.
Comments:
4 pages, 2 figures, Proceedings for Quark Matter 2019
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2002.11752 [pdf]
NPA(2021)·3 citations
02
[Submitted on 27 Feb 2020]
Extremely large matter radii in $^{49 - 51}$ Ca isotopes and the $0^{+}$ breathing mode states of $^{48}$ Ca
Syed Afsar Abbas · Anisul Ain Usmani · Usuf Rahaman
Through inelastic scattering cross section measurements for $^{42 - 51}$ Ca on a carbon target at 280 MeV/nucleon recently, Tanaka {\it et al.} [ arXiv:1911.05262 [nucl-ex]], in a very significant experiment, have demonstrated large swelling of doubly magic $^{48}$ Ca core in calcium isotopes beyond N=28. The matter radii observed in these experiments, are surprisingly much larger than the corresponding, already amazingly large charge radii of the same calcium isotopes, by Garcia {\it et al.} [Nat. Phys. 12 (2016) 594]. Here we propose a novel solution, wherein the breathing mode states $0^{+}$ of $^{48}$ Ca, provide a global and consistent solution of this matter radii conundrum.
Comments:
5 pages
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2002.12002 [pdf]
0 citations
03
[Submitted on 26 Feb 2020]
Estimations of Cross-Sections for Photonuclear Reaction on Calcium Isotopes by Artificial Neural Networks
S. Akkoyun · H. Kaya
The nuclear reaction induced by photon is one of the important tools in the investigation of atomic nuclei. In the reaction, a target material is bombarded by photons with high-energies in the range of gamma-ray energy range. In the bombarding process, the photons can statistically be absorbed by a nucleus in the target material. Then the excited nucleus can decay by emitting proton, neutron, alpha and light particles or photons. By performing photonuclear reaction on the target, it can be easily investigated low-lying excited states of the nuclei. In the present work, ({\gamma}, n) photonuclear reaction cross-sections on different calcium isotopes have been estimated by using artificial neural network method. The method is a mathematical model that mimics the brain functionality of the creatures. The correlation coefficient values of the method for both training and test phases being 0.99 indicate that the method is very suitable for this purpose.
Comments:
6 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2002.12166 [pdf]
0 citations
04
[Submitted on 27 Feb 2020]
Hydrodynamic response to jets with a source based on causal diffusion
Y. Tachibana🇺🇸 · A. Angerami · S. A. Bass · S. Cao · Y. Chen · J. Coleman · L. Cunqueiro · T. Dai · L. Du · R. Ehlers · H. Elfner · D. Everett and 38 other authors
We study the medium response to jet evolution in the quark-gluon plasma within the JETSCAPE framework. Recoil partons' medium response in the weakly coupled description is implemented in the multi-stage jet energy-loss model in the framework. As a further extension, the hydrodynamic description is rearranged to include in-medium jet transport based on a strong-coupling picture. To interface hydrodynamics with jet energy-loss models, the hydrodynamic source term is modeled by a causal formulation employing the relativistic diffusion equation. The jet shape and fragmentation function are studied via realistic simulations with weakly coupled recoils. We also demonstrate modifications in the medium caused by the hydrodynamic response.
Comments:
4 pages, 2 figures, contribution to the Quark Matter 2019 proceedings
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2002.12250 [pdf]
NPA(2021)·21 citations
05
[Submitted on 27 Feb 2020]
Improved description of light nuclei through chiral effective field theory at leading order
M. Sanchez Sanchez🇫🇷 · N. A. Smirnova🇫🇷 · A. M. Shirokov🇺🇸 · P. Maris🇺🇸 · J. P. Vary🇺🇸
We propose an arrangement of the most commonly invoked version of the two-nucleon chiral potential such that the low-lying amplitude zero of the 1S0 partial wave is captured at leading order of the effective expansion. Adopting other partial waves from the LENPIC interaction, we show how this modification yields an improved description of ground-state energies and point-proton radii of three test nuclei.
Comments:
10 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2002.12258 [pdf]
PRC(2020)·12 citations
06
[Submitted on 26 Feb 2020] (cross-list from hep-ph)
Scalar spectrum in a graviton soft wall model
Matteo Rinaldi🇮🇹 · Vicente Vento🇪🇸
In this study we present a unified phenomenological analysis of the scalar glueball and scalar meson spectra within an AdS/QCD framework in the bottom up approach. For this purpose we generalize the recently developed graviton soft-wall (GSW) model, which has shown an excellent agreement with the lattice QCD glueball spectrum, to a description of glueballs and mesons with a unique energy scale. In this scheme, dilatonic effects, are incorporated in the metric as a deformation of the AdS space. We apply the model also to the heavy meson spectra with success. We obtain quadratic mass equations for all scalar mesons while the glueballs satisfy an almost linear mass equation. Besides their spectra, we also discuss the mixing of scalar glueball and light scalar meson states within a unified framework: the GSW model. To this aim, the light-front holographic approach, which connects the mode functions of AdS/QCD to the light-front wave functions, is applied. This relation provides the probabilistic interpretation required to properly investigate the mixing conditions.
Comments:
10 pages, 13 figures. Accepted version on J.Phys G. The analysis on heavy scalar mesons has been included
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2002.11720 [pdf]
J.Phys.G(2020)·20 citations
07
[Submitted on 26 Feb 2020] (cross-list from hep-ph)
Shear transport far from equilibrium via holography
Michael F. Wondrak🇩🇪 · Matthias Kaminski🇺🇸 · Marcus Bleicher🇩🇪
In heavy-ion collisions, the quark-gluon plasma is produced far from equilibrium. This regime is currently inaccessible by quantum chromodynamics (QCD) computations. We calculate shear transport and entropy far from equilibrium in a holographic model, defining a time-dependent ratio of shear viscosity to entropy density, $η / s$ . Large deviations of up to 60% from its near-equilibrium value, $1/4 π$ , are found for realistic situations at the Large Hadron Collider. We predict the far-from-equilibrium time-dependence of $η / s$ to substantially affect the evolution of the QCD plasma and to impact the extraction of QCD properties from flow coefficients in heavy-ion collision data.
Comments:
10 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2002.11730 [pdf]
PLB(2020)·20 citations
08
[Submitted on 27 Feb 2020] (cross-list from nucl-ex)
Long-range collectivity in small collision-systems with two- and four-particle correlations @ STAR
Roy A. Lacey (for the STAR Collaboration)🇺🇸
New STAR differential and integral v{2,3} measurements that explicitly account for non-flow contributions are reported for p/d/3He+Au, collisions at Roots=200 GeV. The measurements, which leverage the two-particle correlators for p/d/3He+Au and minimum-bias p+p collisions in tandem with three well-established methods of non-flow subtraction, are observed to be method-independent. For comparable multiplicities, they further indicate system-independent v2{2} and v3{2} values that are consistent with the critical role of both size (N{ch}) and the subnucleonic-fluctuations-driven eccentricities e{2,3} but are inconsistent with the notion of shape engineering in p/d/3He+Au collisions. The scaling function derived from the measurements, confirm the important role of final-state effects across a broad spectrum of collision-system sizes and energies and suggests an increase in eta/s(T,muB) for small collision-systems.
Comments:
Contribution to the proceedings of QM2019
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2002.11889 [pdf]
NPA(2021)·14 citations
09
[Submitted on 27 Feb 2020] (cross-list from hep-lat)
New developments in lattice QCD on equilibrium physics and phase diagram
Heng-Tong Ding🇨🇳
I review recent new lattice QCD results on a few selected topics which are relevant to the heavy ion physics community. Special emphasis is put on the QCD phase diagram towards the chiral limit and at nonzero baryon density as well as the fate of quarkonia and heavy quark drag coefficients.
Comments:
8 pages, 5 figures, plenary talk given at the XXVIIIth International Conference on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2019), November 4th-9th 2019, Wuhan, China
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2002.11957 [pdf]
NPA(2021)·38 citations
10
[Submitted on 27 Feb 2020] (cross-list from hep-ph)
Pole analysis on the hadron spectroscopy of $Λ_{b} \to J /Ψ p K^{-}$
Shi-Qing Kuang🇨🇳 · Ling-Yun Dai🇨🇳 · Xian-Wei Kang🇨🇳 · De-Liang Yao🇨🇳
In this paper we study the $J /Ψ p$ spectroscopy in the process of $Λ_{b} \to J /Ψ p K^{-}$ . The final state interactions of coupled channel $J /Ψ p$ ~-~ $D ˉ Σ_{c}$ ~-~ $D ˉ^{*} Σ_{c}$ are constructed based on K-matrix with the Chew-Mandelstam function. We build the $Λ_{b} \to J /Ψ p K^{-}$ amplitude according to the Au-Morgan-Pennington method. The event shape is fitted and the decay width of $Λ_{b} \to J /Ψ p K^{-}$ is used to constrain the parameters, too. With the amplitudes we extract out the poles and their residues. Our amplitude and pole analysis suggest that the $P_{c} (4312)$ should be $D ˉ Σ_{c}$ molecule, the $P_{c} (4440)$ could be an S-wave compact pentaquark state, and the structure around $P_{c} (4457)$ is caused by the cusp effect. The future experimental measurement of the decays of $Λ_{b} \to D ˉ Σ_{c} K^{-}$ and $Λ_{b} \to D ˉ^{*} Σ_{c} K^{-}$ would further help to study the nature of these resonances.
Comments:
updated to the published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2002.11959 [pdf]
EPJC(2020)·42 citations
11
[Submitted on 25 Feb 2020] (cross-list from hep-ph)
Probing Nucleons and Nuclei in High Energy Collisions
Christine A. Aidala · Elke Aschenauer · Fatma Aslan · Alessandro Bacchetta · Ian Balitsky · Sanjin Benic · Shohini Bhattacharya · Mariaelena Boglione · Matthias Burkardt · Justin Cammarota · Giovanni A. Chirilli · Christopher Cocuzza and 78 other authors
This volume is a collection of contributions for the 7-week program "Probing Nucleons and Nuclei in High Energy Collisions" that was held at the Institute for Nuclear Theory in Seattle, WA, USA, from October 1 until November 16, 2018. The program was dedicated to the physics of the Electron Ion Collider (EIC), the world's first polarized electron-nucleon (ep) and electron-nucleus (eA) collider to be constructed in the USA. These proceedings are organized by chapters, corresponding to the weeks of the program: Week I, Generalized parton distributions; Week II, Transverse spin and TMDs; Week III, Longitudinal spin; Week IV, Symposium week; Weeks V & VI, eA collisions; Week VII, pA and AA collisions. We hope these proceedings will be useful to readers as a compilation of EIC-related science at the end of the second decade of the XXI century.
Comments:
Electron Ion Collider, INT 18-3 Program. Published by World Scientific. Duplicates content of arXiv:1912.10965, arXiv:1912.10724, arXiv:1910.03006, arXiv:1910.07982, arXiv:1912.13397, arXiv:1910.01979, arXiv:2001.07862, arXiv:2001.03700, arXiv:1910.01030, arXiv:1910.01273, arXiv:1912.13020, arXiv:1910.06003, arXiv:2001.03655, arXiv:1909.12591, arXiv:1909.09809, arXiv:1910.04806, arXiv:2001.05978
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2002.12333 [pdf]
90 citations

Affiliations

first authorsco-authorsvia INSPIRE