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Nuclear Theory·nucl-th

Thursday·August 19, 2021

11 papers—4 primary·7 cross-listed

All11Primary4Cross-lists7
  1. 01

    [Submitted on 18 Aug 2021]

    Interplay between core and corona components in high-energy nuclear collisions

    Yuuka Kanakubo🇯🇵 · Yasuki Tachibana🇯🇵 · Tetsufumi Hirano🇯🇵

    We establish the updated version of dynamical core--corona initialization framework (DCCI2) as a unified description from small to large colliding systems and from low to high transverse momentum () regions. Using DCCI2, we investigate effects of interplay between locally equilibrated and non-equilibrated systems, in other words, core and corona components in high-energy nuclear collisions. Given experimental multiplicity distributions and yield ratios of baryons to charged pions as inputs, we extract the fraction of core and corona components in p+p collisions at TeV and Pb+Pb collisions at TeV. We find core contribution overtakes corona contribution as increasing multiplicity above regardless of the collision system or energy. We also see that the core contribution exceeds the corona contribution only in 0.0-0.95\% multiplicity class in p+p collisions. Notably, there is a small enhancement of corona contribution with \% below GeV even in minimum bias Pb+Pb collisions. We find that the corona contribution at low gives - correction on at . This raises a problem in conventional hydrodynamic analyses in which low soft hadrons originate solely from core components. We finally scrutinize the roles of string fragmentation and the longitudinal expansion in the transverse energy per unit rapidity, which is crucial in initial conditions for hydrodynamics from event generators based on string models.

    Comments:
    25 pages, 9 figures (bug in viewing PDF file is fixed)
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2108.07943 [pdf]
    PRC(2022)·45 citations
  2. 02

    [Submitted on 18 Aug 2021]

    Nucleon-nucleon correlations in the extreme oxygen isotopes

    S. M. Wang · W. Nazarewicz · R. J. Charity · L. G. Sobotka

    There has been an upsurge of interest in two-nucleon decays thanks to the studies of nucleon-nucleon correlations. In our previous work, based on a novel time-dependent three-body approach, we demonstrated that the energy and angular correlations of the emitted nucleons can shed light on the structure of nucleonic pairs formed inside the nucleus. In this work, we apply the new framework to study the decay dynamics and properties of some extreme proton-rich and neutron-rich oxygen isotopes, including two-proton () decays of O and two-neutron () decay of O. Here we show that the low- components of O wave functions, which are affected by continuum and configuration-interaction effects, strongly impact decay dynamics and asymptotic correlations. In the calculated wave functions of O, diproton and cigarlike structures merge together during the tunneling process and the resulting energy- and angular correlations are very consistent with the experimental data. The asymptotic correlations of the decay of O dramatically change as the two-neutron decay energy approaches the zero-energy threshold. The small reported value of suggests that the decay of this nucleus can be understood in terms of the universal phase-space limit.

    Comments:
    7 pages, 4 figures. arXiv admin note: text overlap with arXiv:2104.03195
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2108.08007 [pdf]
    J.Phys.G(2022)·20 citations
  3. 03

    [Submitted on 18 Aug 2021]

    Bottomonium suppression and flow in heavy-ion collisions

    Michael Strickland🇺🇸

    The strong suppression of bottomonia production in ultra-relativistic heavy-ion collisions is a smoking gun for the creation of a deconfined quark-gluon plasma (QGP). In this proceedings contribution, I review recent work that aims to provide a more comprehensive and systematic understanding of bottomonium dynamics in the QGP through the use of pNRQCD and an open quantum systems approach. This approach allows one to evolve the heavy-quarkonium reduced density matrix, taking into account non-unitary effective Hamiltonian evolution of the wave-function and quantum jumps between different angular momentum and color states. In the case of a strong coupled QGP in which E << T,m_D << 1/a_0, the corresponding evolution equation is Markovian and can therefore be mapped to a Lindblad evolution equation. To solve the resulting Lindblad equation, we make use of a stochastic unraveling called the quantum trajectories algorithm and couple the non-abelian quantum evolution to a realistic 3+1D viscous hydrodynamical background. Using a large number of Monte-Carlo sampled bottomonium trajectories, we make predictions for bottomonium R_AA and elliptic flow as a function of centrality and transverse momentum and compare to data collected by the ALICE, ATLAS, and CMS collaborations.

    Comments:
    6 pages, 3 figures; Plenary contribution to Strangeness in Quark Matter 2021 (Virtual)
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2108.08160 [pdf]
    EPJ Web Conf.(2022)·2 citations
  4. 04

    [Submitted on 18 Aug 2021]

    Toward emulating nuclear reactions using eigenvector continuation

    C. Drischler🇺🇸 · M. Quinonez🇺🇸 · P. G. Giuliani🇺🇸 · A. E. Lovell🇺🇸 · F. M. Nunes🇺🇸

    We construct an efficient emulator for two-body scattering observables using the general (complex) Kohn variational principle and trial wave functions derived from eigenvector continuation. The emulator simultaneously evaluates an array of Kohn variational principles associated with different boundary conditions, which allows for the detection and removal of spurious singularities known as Kohn anomalies. When applied to the -matrix only, our emulator resembles the one constructed by Furnstahl et al. [Phys. Lett. B 809, 135719] although with reduced numerical noise. After a few applications to real potentials, we emulate differential cross sections for Ca scattering based on a realistic optical potential and quantify the model uncertainties using Bayesian methods. These calculations serve as a proof of principle for future studies aimed at improving optical models.

    Comments:
    12 pages, 4 figures, 1 table; minor improvements, close to published version
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2108.08269 [pdf]
    PLB(2021)·69 citations

Affiliations

first authorsco-authorsvia INSPIRE