Nuclear Theory·nucl-th

Thursday·February 6, 2020

8 papers—4 primary·4 cross-listed

01
[Submitted on 5 Feb 2020]
$p_{T}$ -dependent multiplicity fluctuations from PCA and initial conditions
Fernando G. Gardim🇧🇷 · Frédérique Grassi🇧🇷 · Pedro Ishida🇧🇷 · Matthew Luzum🇧🇷 · Jean-Yves Ollitrault🇫🇷
We present a Principal Component Analysis for a hydrodynamic simulation and compare with CMS experimental data. While the results are reasonable for anisotropic flow, for multiplicity fluctuations they are qualitatively different. We argue that this is due to too large transverse momentum ( $p_{T}$ ) fluctuations and $N - p_{T}$ covariance in the simulation than seen experimentally. In turn this is related to too large initial size fluctuations.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2002.01747 [pdf]
NPA(2021)·3 citations
02
[Submitted on 5 Feb 2020]
How accurately can the Extended Thomas-Fermi method describe the inner crust of a neutron star?
Matthew Shelley · Alessandro Pastore
We perform a systematic comparison between the results obtained by solving fully self-consistently the Hartree-Fock-Bogoliubov equations, and those obtained using the semi-classical Extended Thomas-Fermi method, for various Wigner-Seitz cells within the inner crust of a neutron star. The lack of pairing correlations in the semi-classical approach leads to a large discrepancy between the two approaches. This discrepancy is well beyond the error of the quantum-mechanical calculation, and is related to spurious shell effects in the neutron gas.
Comments:
10 pages, 5 figures, accepted for publication in Journal of Physics: Conference Series
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2002.01839 [pdf]
J.Phys.Conf.Ser.(2020)·6 citations
03
[Submitted on 5 Feb 2020]
Model nuclear energy density functionals derived from ab initio calculations
G. Salvioni · J. Dobaczewski · C. Barbieri · G. Carlsson · A. Idini · A. Pastore
We present the first application of a new approach, proposed in [Journal of Physics G: Nuclear and Particle Physics, 43, 04LT01 (2016)] to derive coupling constants of the Skyrme energy density functional (EDF) from ab initio Hamiltonian. By perturbing the ab initio Hamiltonian with several functional generators defining the Skyrme EDF, we create a set of metadata that is then used to constrain the coupling constants of the functional. We use statistical analysis to obtain such an ab initio-equivalent Skyrme EDF. We find that the resulting functional describes properties of atomic nuclei and infinite nuclear matter quite poorly. This may point out to the necessity of building up the ab initio-equivalent functionals from more sophisticated generators. However, we also indicate that the current precision of the ab initio calculations may be insufficient for deriving meaningful nuclear EDFs.
Comments:
24 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2002.01903 [pdf]
J.Phys.G(2020)·19 citations
04
[Submitted on 5 Feb 2020]
From Chiral Kinetic Theory To Spin Hydrodynamics
Shuzhe Shi🇨🇦 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦
The total angular momentum is conserved in the evolution of the Quark-Gluon Plasma (QGP) created in heavy-ion collision, and consists of two sectors: the orbital angular momentum (OAM) caused by kinetic motion, and the spin, an intrinsic degree of freedom of quarks and gluons. Microscopic scattering processes allow the conversion between these two components, hence the spin density could eventually have non-trivial influence on the QGP evolution. A hydrodynamic theory, with the spin polarization effect properly taken into account, is required to quantitatively study the polarization rate for observed hadrons, e.g. the $Λ$ -hyperon. In this work, we start with chiral kinetic theory and construct the spin hydrodynamic framework for a chiral spinor system. We obtain the equations of motion of second-order dissipative relativistic fluid dynamics with non-trivial spin polarization density.
Comments:
4 pages, contribution to the proceeding of XXVIIIth International Conference on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2019)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2002.01911 [pdf]
NPA(2021)·22 citations
05
[Submitted on 4 Feb 2020] (cross-list from hep-ph)
Medium-induced gluon radiation with full resummation of multiple scatterings for realistic parton-medium interactions
Carlota Andres🇺🇸 · Liliana Apolinário🇵🇹 · Fabio Dominguez🇪🇸
The new precision era of jet quenching observables at both RHIC and the LHC calls for an improved and more precise description of in-medium gluon emissions. The development of new theoretical tools and analytical calculations to tackle this challenge has been hampered by the inability to include the effects of multiple scatterings with the medium using a realistic model for the parton-medium interactions. In this paper, we show how the analytical expressions for the full in-medium spectrum, including the resummation of all multiple scatterings, can be written in a form where the numerical evaluation can be easily performed without the need of the usually employed harmonic or single hard approximations. We present the transverse momentum and energy-dependent medium-induced gluon emission distributions for known realistic interaction models to illustrate how our framework can be applied beyond the limited kinematic regions of previous calculations.
Comments:
21 pages, 8 figures. Figure 5 corrected, new Figures 7 and 8, discussion improved, and new appendix B. Matches published JHEP version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2002.01517 [pdf]
JHEP(2020)·86 citations
06
[Submitted on 5 Feb 2020] (cross-list from hep-ph)
QCD factorization and universality of jet cross sections in heavy-ion collisions
Jian-Wei Qiu🇺🇸 · Felix Ringer🇺🇸 · Nobuo Sato🇺🇸 · Pia Zurita🇩🇪
We review a recently proposed phenomenological framework to establish the notions of QCD factorization and universality of jet cross sections in the heavy-ion environment. First results of a global analysis of the nuclear modification factor of inclusive jets are presented where we extract medium modified jet functions using a Monte Carlo sampling approach. We observe that gluon jets are significantly more suppressed than quark jets. In addition, we study the jet radius dependence of the inclusive jet cross section in heavy-ion collisions and comment on a recent measurement from CMS. By considering for example jet substructure observables it will be possible to test the universality of the extracted medium jet functions. We thus expect that the presented results will eventually allow for extractions of medium properties with a reduced model bias.
Comments:
4 pages, 2 figures, XXVIIIth International Conference on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2019)
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2002.01652 [pdf]
NPA(2021)·7 citations
07
[Submitted on 5 Feb 2020] (cross-list from hep-lat)
Contraction Diagram Analysis in Pion-Kaon Scattering
Chaitra Kalmahalli Guruswamy🇩🇪 · Ulf-G. Meißner🇩🇪 · Chien-Yeah Seng🇩🇪
We study the contributions from the connected and disconnected contraction diagrams to the pion-kaon scattering amplitude within the framework of SU $(4∣1)$ partially-quenched chiral perturbation theory. Combining this with a finite-volume analysis, we demonstrate that a lattice calculation of the easier computable connected correlation functions is able to provide valuable information of the noisier disconnected correlation functions, and may serve as a theory guidance for the future refinement of the corresponding lattice techniques.
Comments:
Version to appear in Nuclear Physics B
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2002.01763 [pdf]
NPB(2020)·5 citations
08
[Submitted on 5 Feb 2020] (cross-list from hep-lat)
Higher order cumulants of net baryon-number distributions at non-zero $μ_{B}$
Dennis Bollweg🇩🇪 · Frithjof Karsch🇩🇪 · Swagato Mukherjee🇺🇸 · Christian Schmidt🇩🇪
Using recent results on higher order cumulants of conserved charge fluctuations from lattice QCD, we construct mean, variance, skewness, kurtosis, hyper-skewness and hyper-kurtosis of net-baryon number distributions for small baryon chemical potentials $μ_{B}$ . For the strangeness neutral case ( $μ_{S} = 0$ ) at fixed ratio of electric charge to baryon number density ( $\frac{n _{Q}}{n _{B}} = 0.4$ ), which is appropriate for a comparison with heavy ion collisions, we present results for $κ_{B} σ_{B}^{2}$ , $S_{B} σ_{B}^{3} / M_{B}$ , $κ_{B}^{H} σ_{B}^{4}$ and $S_{B}^{H} σ_{B}^{5} / M_{B}$ on the crossover line for the chiral transition, $T_{p c} (μ_{B})$ . Continuum extrapolations for this pseudo-critical transition line have recently been reported by HotQCD up to baryon chemical potentials $μ_{B} ≃ 300$ MeV [arXiv:1812.08235]. These cumulant ratios are of direct relevance for comparisons with corresponding ratios measured by STAR in the BES-I and II runs at beam energies $s_{N N} \geq 20$ GeV. In particular, we point out that recent high statistics results on skewness and kurtosis of net-baryon number distributions obtained by STAR at $s_{N N} = 54.4$ GeV put strong constraints on freeze-out parameters and are consistent with predictions from thermal QCD.
Comments:
4 pages, 6 figures, Contribution to the Quark Matter 2019 Conference Proceedings
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2002.01837 [pdf]
NPA(2021)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE