Nuclear Theory·nucl-th

Friday·May 21, 2021

9 papers—4 primary·5 cross-listed

01
Elliptic flow splittings in the Polyakov-looped Nambu-Jona Lasinio transport model
Wen-Hao Zhou🇨🇳 · He Liu🇨🇳 · Feng Li🇨🇳 · Yi-Feng Sun🇮🇹 · Jun Xu🇨🇳 · Che Ming Ko🇺🇸
To incorporate the effect of gluons on the evolution dynamics of the quark matter produced in relativistic heavy-ion collisions, we extend the 3-flavor Nambu-Jona-Lasinio (NJL) transport model to include the contribution from the Polyakov loops. Imbedding the resulting pNJL partonic transport model in an extended multiphase transport (extended AMPT) model, we then study the elliptic flow splittings between particles and their antiparticles in relativistic heavy-ion collisions at RHIC-BES energies. We find that a weak quark vector interaction in the partonic phase is able to describe the elliptic flow splitting between protons and antiprotons in heavy-ion collisions at $s_{N N} = 7.7$ to 39 GeV. Knowledge on the quark vector interaction is useful for understanding the equation of state of quark matter at large baryon chemical potentials and thus the location of the critical point in the QCD phase diagram.
nucl-thhep-exnucl-exPRC(2021)·9 citations
02
$Λ (1405)$ mediated triangle singularity in the $K^{-} d \to p Σ^{-}$ reaction
Albert Feijoo🇪🇸 · Raquel Molina🇪🇸 · Lian Rong Dai🇨🇳 · Eulogio Oset🇪🇸
We study for the first time the $p Σ^{-} \to K^{-} d$ and $K^{-} d \to p Σ^{-}$ reactions close to threshold and show that they are driven by a triangle mechanism, with the $Λ (1405)$ , a proton and a neutron as intermediate states, which develops a triangle singularity close to the $K ˉ d$ threshold. We find that a mechanism involving virtual pion exchange and the $K^{-} p \to π^{+} Σ^{-}$ amplitude dominates over another one involving kaon exchange and the $K^{-} p \to K^{-} p$ amplitude. Moreover, of the two $Λ (1405)$ states, the one with higher mass around $1420$ MeV, gives the largest contribution to the process. We show that the cross section, well within measurable range, is very sensitive to different models that, while reproducing $K ˉ N$ observables above threshold, provide different extrapolations of the $K ˉ N$ amplitudes below threshold. The observables of this reaction will provide new constraints on the theoretical models, leading to more reliable extrapolations of the $K ˉ N$ amplitudes below threshold and to more accurate predictions of the $Λ (1405)$ state of lower mass.
nucl-thEPJC(2022)·6 citations
03
Parity Partner Bands in $^{163}$ Lu: A novel approach for describing the negative parity states from a triaxial super-deformed band
R. Poenaru · A. A. Raduta
The wobbling spectrum of $^{163}$ Lu is described through a novel approach, starting from a triaxial rotor model within a semi-classical picture, and obtaining a new set of equations for all four rotational bands that have wobbling character. Redefining the band structure in the present model is done by adopting the concepts of Signature Partner Bands and Parity Partner Bands. Indeed, describing a wobbling spectrum in an even-odd nucleus through signature and parity quantum numbers is an inedited interpretation of the triaxial super-deformed bands.
nucl-thIJMPE(2021)·0 citations
04
Considering non-locality in the optical potentials within eikonal models
Chloë Hebborn🇺🇸 · Filomena M. Nunes🇺🇸
Background: For its simplicity, the eikonal method is the tool of choice to analyze nuclear reactions at high energies ( $E > 100$ MeV/nucleon), including knockout reactions. However, so far, the effective interactions used in this method are assumed to be fully local. Purpose: Given the recent studies on non-local optical potentials, in this work we assess whether non-locality in the optical potentials is expected to impact reactions at high energies and then explore different avenues for extending the eikonal method to include non-local interactions. Method: We compare angular distributions obtained for non-local interactions (using the exact R-matrix approach for elastic scattering and the adiabatic distorted wave approximation for transfer) with those obtained using their local-equivalent interactions. Results: Our results show that transfer observables are significantly impacted by non-locality in the high-energy regime. Because knockout reactions are dominated by stripping (transfer to inelastic channels), non-locality is expected to have a large effect on knockout observables too. Three approaches are explored for extending the eikonal method to non-local interactions, including an iterative method and a perturbation theory. Conclusions: None of the derived extensions of the eikonal model provide a good description of elastic scattering. This work suggests that non-locality removes the formal simplicity associated with the eikonal model.
nucl-thPRC(2021)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE

Elliptic flow splittings in the Polyakov-looped Nambu-Jona Lasinio transport model

Λ(1405) mediated triangle singularity in the K−d→pΣ− reaction

Parity Partner Bands in 163Lu: A novel approach for describing the negative parity states from a triaxial super-deformed band

Considering non-locality in the optical potentials within eikonal models

Affiliations

$Λ (1405)$ mediated triangle singularity in the $K^{-} d \to p Σ^{-}$ reaction

Parity Partner Bands in $^{163}$ Lu: A novel approach for describing the negative parity states from a triaxial super-deformed band