Nuclear Theory·nucl-th

Tuesday·April 24, 2018

14 papers—8 primary·6 cross-listed

09
Lattice QCD and heavy ion collisions: a review of recent progress
Claudia Ratti🇺🇸
In the last few years, numerical simulations of QCD on the lattice have reached a new level of accuracy. A wide range of thermodynamic quantities is now available in the continuum limit and for physical quark masses. This allows a comparison with measurements from heavy ion collisions for the first time. Furthermore, calculations of dynamical quantities are also becoming available. The combined effort from first principles and experiment allows us to gain an unprecedented understanding of the properties of quark-gluon plasma. I will review the state-of-the-art results from lattice simulations and connect them to the experimental information from RHIC and the LHC.
↳ hep-lathep-phnucl-thRept.Prog.Phys.(2018)·272 citations
10
Electrical conductivity of Hot and Dense QCD matter at RHIC BES energies: A Color String Percolation Approach
Pragati Sahoo🇮🇳 · Swatantra Kumar Tiwari🇮🇳 · Raghunath Sahoo🇮🇳
Recently, transport coefficients viz. shear viscosity, electrical conductivity etc. of strongly interacting matter produced in heavy-ion collisions have drawn considerable interest. We study the normalised electrical conductivity ( $σ_{el}$ /T) of hot QCD matter as a function of temperature (T) using the Color String Percolation Model (CSPM). We also study the temperature dependence of shear viscosity and its ratio with electrical conductivity for the QCD matter. We compare CSPM estimations with various existing results and lattice Quantum Chromodynamics (lQCD) predictions with (2+1) dynamical flavours. We find that $σ_{el}$ /T in CSPM has a very weak dependence on the temperature. We compare CSPM results with those obtained in Boltzmann Approach to Multi-Parton Scatterings (BAMPS) model. A good agreement is found between CSPM results and predictions of BAMPS with fixed strong coupling constant.
↳ hep-phhep-exnucl-exnucl-thPRD(2018)·21 citations
11
Analyses of multiplicity distributions and Bose-Einstein correlations at the LHC using negative binomial distribution and generalized Glauber-Lachs formula
Minoru Biyajima🇯🇵 · Takuya Mizoguchi🇯🇵
This study aims to analyze the data on multiplicity distributions and Bose-Einstein correlations collected at the LHC by the ATLAS and CMS Collaborations using a double-generalized Glauber-Lachs formula (D-GGL) and double-negative binomial distribution (D-NBD). From this investigation, it can be inferred that the D-GGL formula performs as effectively as the D-NBD. Moreover, our results show that the parameters estimated in multiplicity distributions (MD) (P(n)) are related to those contained in the BEC formula.
↳ hep-phnucl-thEPJA(2018)·7 citations
12
Matching of transverse momentum dependent distributions at twist-3
Ignazio Scimemi🇪🇸 · Alexey Vladimirov🇩🇪
We derive the leading order matching of the quark generated polarized transverse momentum dependent (TMD) distributions onto the collinear functions at small values of the transverse distance. Starting from the very definition of the TMD operator and performing the light-cone operator product expansion up to twist-3 order, we evaluate each distribution directly in position space. We primarily consider the cases of Sivers, Boer-Mulders and worm-gear functions. The effects of the TMD process dependence on the matching are explicitly shown. We also discuss the moments of TMD distributions which can be relevant for lattice calculations.
↳ hep-phhep-exhep-latnucl-ex+1EPJC(2018)·47 citations
13
Photoneutron cross sections for Ni isotopes: Toward understanding $(n, γ)$ cross sections relevant to the weak s-process nucleosynthesis
H. Utsunomiya🇯🇵 · T. Renstrøm🇳🇴 · G. M. Tveten🇳🇴 · S. Goriely🇧🇪 · S. Katayama🇯🇵 · T. Ari-izumi🇯🇵 · D. Takenaka🇯🇵 · D. Symochko🇩🇪 · B. V. Kheswa🇳🇴 · V.W. Ingeberg🇳🇴 · T. Glodariu🇷🇴 · Y.-W. Lui🇺🇸 and 10 other authors
Photoneutron cross sections were measured for $^{58}$ Ni, $^{60}$ Ni, $^{61}$ Ni, and $^{64}$ Ni at energies between the one-neutron and two-neutron thresholds using quasi-monochromatic $γ$ -ray beams produced in laser Compton-scattering at the NewSUBARU synchrotron radiation facility. The new photoneutron data are used to extract the $γ$ -ray strength function above the neutron threshold complementing the information obtained by the Oslo method below the threshold. We discuss radiative neutron capture cross sections and the Maxwellian-averaged cross sections for Ni isotopes including $^{63}$ Ni, a branching point nucleus along the weak s-process path. The cross sections are calculated with the experimentally constrained $γ$ -ray strength functions from the Hartree-Fock-Bogolyubov plus quasi-particle-random phase approximation based on the Gogny D1M interaction for both $E 1$ and $M 1$ components and supplemented with the $M 1$ upbend.
↳ nucl-exnucl-thPRC(2018)·22 citations
14
Covariant quark model for the electromagnetic structure of light nucleon resonances
G. Ramalho🇧🇷
We present estimates from the covariant spectator quark model for the electromagnetic transition form factors for the resonances $N (1440) \frac{1}{2}^{+}$ , $N (1535) \frac{1}{2}^{-}$ , $N (1520) \frac{3}{2}^{-}$ and $Δ (1232) \frac{3}{2}^{+}$ , at intermediate and large square momentum transfer ( $Q^{2}$ ). The calculations associated to the $N (1440) \frac{1}{2}^{+}$ , $N (1535) \frac{1}{2}^{-}$ and $N (1520) \frac{3}{2}^{-}$ states are based exclusively on the parametrizations derived for the nucleon. In the case of the $Δ (1232) \frac{3}{2}^{+}$ (isospin 3/2), we use lattice QCD data to estimate the radial structure, and take into account the well known effects associated with the pion cloud dressing of the baryons. Our estimates are based mainly on the valence quark degrees of freedom and are in good agreement with the data for $Q^{2} > 2$ GeV $^{2}$ , with a few exceptions. The present predictions can be tested in a near future for large $Q^{2}$ at the Jefferson Lab -- 12 GeV upgrade.
↳ hep-phhep-exhep-latnucl-ex+10 citations

Affiliations

first authorsco-authorsvia INSPIRE

Lattice QCD and heavy ion collisions: a review of recent progress

Electrical conductivity of Hot and Dense QCD matter at RHIC BES energies: A Color String Percolation Approach

Analyses of multiplicity distributions and Bose-Einstein correlations at the LHC using negative binomial distribution and generalized Glauber-Lachs formula

Matching of transverse momentum dependent distributions at twist-3

Photoneutron cross sections for Ni isotopes: Toward understanding (n,γ) cross sections relevant to the weak s-process nucleosynthesis

Covariant quark model for the electromagnetic structure of light nucleon resonances

Affiliations

Photoneutron cross sections for Ni isotopes: Toward understanding $(n, γ)$ cross sections relevant to the weak s-process nucleosynthesis