Nuclear Theory·nucl-th

Monday·October 26, 2020

9 papers—8 primary·1 cross-listed

01
The Multiplicity Dependence of Pion Interferometry in Hydrodynamics
Christopher Plumberg🇺🇸
Understanding the origins of collective, fluid-like behavior in ultrarelativistic nuclear collisions constitutes one of the biggest open challenges in the field. In this Letter, it is argued that certain features in the multiplicity dependence of the source sizes extracted using pion interferometry may be understood quite naturally if small systems evolve hydrodynamically at sufficiently large multiplicities. Interferometry may therefore provide a baseline for probing and constraining the nature of collective behavior in nuclear collisions.
nucl-thnucl-ex4 citations
02
Generalized parton distributions of light nuclei
Sara Fucini🇮🇹 · Matteo Rinaldi🇮🇹 · Sergio Scopetta🇮🇹
The measurement of nuclear generalized parton distributions (GPDs) in hard exclusive processes, such as deeply virtual Compton Scattering (DVCS), will be one of the main achievements of a new generation of experiments at high luminosity, such as those under way at the Jefferson Laboratory (JLab) with the 12 GeV electron beam and, above all, those planned at the future Electron Ion Collider. The CLAS collaboration at JLab has recently demonstrated the possibility to disentangle the two different channels of nuclear DVCS, the coherent and incoherent ones, a first step towards the measurement of GPDs of nuclei and of bound nucleons, respectively, opening new exciting perspectives in the field. In this scenario, theoretical precise calculations, ultimately realistic, become mandatory. Light nuclei, for which realistic studies are affordable and conventional nuclear effects can be safely estimated, so that possible exotic effects can be exposed, play an important role. The status of the calculation of GPDs for light nuclei will be summarized, in particular for $^{3}$ He and $^{4}$ He, and some updates will be presented. The prospects for the next years, related to the new series of measurements at future facilities, will be addressed.
nucl-thhep-phFew Body Syst.(2021)·6 citations
03
Investigation of $Ξ^{-} nn$ ( $S = - 2$ ) Hypernucleus in Low-energy Pionless Halo Effective Theory
Ghanashyam Meher🇮🇳 · Udit Raha🇮🇳
In the strangeness $S = - 2$ sector, we study the $Ξ^{-} nn$ ( $I = 3/2, J^{P} = 1/2^{+}$ ) three-body system using pionless halo effective field theory (EFT), which provides a systematic model independent framework for assessing the feasibility of light particle-stable three-body bound states, utilizing low-energy universality. Here we take recourse to a simplistic speculation of the three-body system by eliminating the repulsive spin-singlet $Ξ^{-} n$ sub-system, while retaining the predominantly attractive (possibly bound) spin-triplet $Ξ^{-} n$ and the virtual bound spin-singlet $nn$ sub-system. In particular, a qualitative leading order EFT investigation by introducing a sharp momentum (ultraviolet) cut-off parameter $Λ_{c}$ into the Faddeev-like coupled integral equations, indicates a discrete scaling behavior akin to a renormalization group limit cycle, thereby suggesting the formal existence of Efimov states in the unitary limit, as $Λ_{c} \to \infty$ . Our subsequent non-asymptotic analysis indicates that the three-body binding energy $B_{3}$ is sensitively dependent on the cut-off without the inclusion of three-body contact interactions. Furthermore, our analysis reproduces several values of the binding energy $B_{3} \sim 3 - 4$ MeV, predicted in context of existing potential models, with the regulator $Λ_{c}$ in the range, $\sim 350 - 460$ MeV. Finally, based on these model inputs for $B_{3}$ , a ballpark estimate of the three-body scattering length in the range, $2.6 - 4.9$ fm, is naively constrained by our EFT analysis, ostensibly demonstrating the universal nature of three-body correlations that is likely to manifest themselves in a halo-bound $Ξ^{-} nn$ system.
nucl-thhep-phEur.Phys.J.ST(2021)·2 citations
04
Towards a power counting in nuclear energy-density-functional theories through a perturbative analysis
Stefano Burrello🇫🇷 · Marcella Grasso🇫🇷 · Chieh-Jen Yang🇸🇪
We illustrate a step towards the construction of a power counting in energy-density-functional (EDF) theories, by analyzing the equations of state (EOSs) of both symmetric and neutron matter. Within the adopted strategy, next-to-leading order (NLO) EOSs are introduced which contain renormalized first-order-type terms and an explicit second-order finite part. Employing as a guide the asymptotic behavior of the introduced renormalized parameters, we focus our analysis on two aspects: (i) With a minimum number of counterterms introduced at NLO, we show that each energy contribution entering in the EOS has a regular evolution with respect to the momentum cutoff (introduced in the adopted regularization procedure) and is found to converge to a cutoff-independent curve. The convergence features of each term are related to its Fermi-momentum dependence. (ii) We find that the asymptotic evolution of the second-order finite-part coefficients is a strong indication of a perturbative behavior, which in turns confirms that the adopted strategy is coherent with a possible underlying power counting in the chosen Skyrme-inspired EDF framework.
nucl-thPLB(2020)·9 citations
05
Recent development of hydrodynamic modeling in heavy-ion collisions
Chun Shen🇺🇸 · Li Yan🇨🇳
We present a concise review of the recent development of relativistic hydrodynamics and its applications to heavy-ion collisions. Theoretical progress on the extended formulation of hydrodynamics towards out-of-equilibrium systems is addressed, emphasizing the so-called attractor solution. On the other hand, recent phenomenological improvements in the hydrodynamic modeling of heavy-ion collisions with respect to the ongoing Beam Energy Scan program, the quantitative characterization of transport coefficients in the three-dimensionally expanding quark-gluon plasma, the fluid description of small colliding systems, and some other interdisciplinary connections are discussed.
nucl-thhep-phnucl-exNucl.Sci.Tech.·187 citations
06
Systematic study of proton radioactivity of spherical proton emitters with Skyrme interactions
Jun-Hao Cheng · Xiao Pan · You-Tian Zou · Xiao-Hua Li · Zhen Zhang · Peng-Cheng Chu
Proton radioactivity is an important and common process of the natural radioactivity of proton-rich nuclei. In our previous work [J. H. Cheng et al., Nucl. Rhys. A 997, 121717 (2020)], we systematically studied the proton radioactivity half-lives of 53< Z <83 nuclei within the two-potential approach with Skyrme-Hartree-Fock. The calculations can well reproduce the experimental data of spherical nuclei. The present work is an extension of the previous work. We systematically study 32 proton radioactivity half-lives of spherical nuclei with the two-potential approach with Skyrme-Hartree-Fock (TPA-SHF) within 115 different versions of the Skyrme interactions. The calculated results indicate that the SLy7 Skyrme interaction gives the lowest r.m.s. deviation in the description of the experimental data of the spherical proton emitters among all the different versions of the Skyrme interactions. In addition, we use this model with the SLy7 Skyrme interaction to predict the proton radioactivity half-lives of 7 spherical nuclei in the same region, whose proton radioactivity is energetically allowed or has been observed but is not yet quantified.
nucl-thEPJA(2020)·9 citations
07
Comparing different density-matrix expansions for long-range pion exchange
L. Zurek · E. A. Coello Pérez · S. K. Bogner · R. J. Furnstahl · A. Schwenk
Empirical energy density functionals (EDFs) are generally successful in describing nuclear properties across the table of nuclides. But their limitations motivate using the density-matrix expansion (DME) to embed long-range pion interactions into a Skyrme functional. Recent results on the impact of the pion were both encouraging and puzzling, necessitating a careful re-examination of the DME implementation. Here we take the first steps, focusing on two-body scalar terms in the DME. Exchange energies with long-range one-pion contributions are well approximated by all DME implementations considered, with preference for variants that do not truncate at two derivatives in every EDF term. The use of the DME for chiral pion contributions is therefore supported by this investigation. For scalar-isovector energies it is important to treat neutrons and protons separately. The results are found to apply under broad conditions, although self-consistency is not yet tested.
nucl-thPRC(2021)·13 citations
08
Isovector pair correlations in analytically solvable models
G. Nikoghosyan · A. Balabekyan · E.A. Kolganova · R.V. Jolos · D.A. Sazonov
The eigensolutions of the collective Hamiltonian with different potentials suggested for description of the isovector pair correlations are obtained, analyzed and compared with the experimental energies. It is shown that the isovector pair correlations in nuclei around $^{56}$ Ni can be described as anharmonic pairing vibrations. The results obtained indicate the presence of the $α$ -particle type correlations in these nuclei and the existence of the interaction different from isovector pairing which also influences on the isospin dependence of the energies.
nucl-thIJMPE(2020)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE