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Nuclear Theory·nucl-th

Monday·September 12, 2016

14 papers—7 primary·7 cross-listed

All14Primary7Cross-lists7
  1. 01

    Natural constraints on the gluon-quark vertex

    Daniele Binosi🇮🇹 · Lei Chang🇨🇳 · Joannis Papavassiliou🇪🇸 · Si-Xue Qin🇺🇸 · Craig D. Roberts🇺🇸

    In principle, the strong-interaction sector of the Standard Model is characterised by a unique renormalisation-group-invariant (RGI) running interaction and a unique form for the dressed--gluon-quark vertex, ; but, whilst much has been learnt about the former, the latter is still obscure. In order to improve this situation, we use a RGI running-interaction that reconciles both top-down and bottom-up analyses of the gauge sector in quantum chromodynamics (QCD) to compute dressed-quark gap equation solutions with 1,660,000 distinct Ansaetze for . Each one of the solutions is then tested for compatibility with three physical criteria and, remarkably, we find that merely 0.55% of the solutions survive the test. Plainly, therefore, even a small selection of observables places extremely tight bounds on the domain of realistic vertex Ansaetze. This analysis and its results should prove useful in constraining insightful contemporary studies of QCD and hadronic phenomena.

    nucl-thhep-lathep-phnucl-exPRD(2017)·120 citations
  2. 02

    Collectivity and electromagnetic radiation in small systems

    Chun Shen🇨🇦 · Jean-François Paquet🇺🇸 · Gabriel S. Denicol🇧🇷 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

    Collective behaviour has been observed in hadronic measurements of high multiplicity proton+lead collisions at the Large Hadron Collider (LHC), as well as in (proton, deuteron, helium-3)+gold collisions at the Relativistic Heavy-Ion Collider (RHIC). To better understand the evolution dynamics and the properties of the matter created in these small systems, a systematic study of the soft hadronic observables together with electromagnetic radiation from these collisions is performed, using a hydrodynamic framework. Quantitative agreement is found between theoretical calculations and existing experimental hadronic observables. The validity of the fluid dynamical description is estimated by calculating Knudsen and inverse Reynolds numbers. Sizeable thermal yields are predicted for low photons. Further predictions of higher order charged hadron anisotropic flow coefficients and of thermal photon enhancement are proposed.

    nucl-thPRC(2017)·155 citations
  3. 03

    Investigating the correlations of flow harmonics in 2.76A TeV Pb--Pb collisions

    Xiangrong Zhu🇨🇳 · You Zhou🇩🇰 · Haojie Xu🇨🇳 · Huichao Song🇨🇳

    This proceeding briefly summarizes our recent investigations on the correlations of flow harmonics in 2.76A TeV Pb--Pb collisions with viscous hydrodynamics {\tt VISH2+1}. We calculated both the symmetric cumulants and the normalized symmetric cumulants , and found and , and , and are correlated, and , and are anti-correlated. We also found are insensitive to the QGP viscosity, which are mainly determined by the initial conditions.

    nucl-thJ.Phys.Conf.Ser.(2017)·0 citations
  4. 04

    Brueckner-Hartree-Fock and its renormalized calculations for finite nuclei

    B. S. Hu · F. R. Xu · Y. Z. Ma · Q. Wu · Z. H. Sun

    We have performed self-consistent Brueckner-Hartree-Fock (BHF) and its renormalized theory to the structure calculations of finite nuclei. The -matrix is calculated within the BHF basis, and the exact Pauli exclusion operator is determined by the BHF spectrum. Self-consistent occupation probabilities are included in the renormalized Brueckner-Hartree-Fock (RBHF). Various systematics and convergences are studies. Good results are obtained for the ground-state energy and radius. RBHF can give a more reasonable single-particle spectrum and radius. We present a first benchmark calculation with other {\it ab initio} methods using the same effective Hamiltonian. We find that the BHF and RBHF results are in good agreement with other methods.

    nucl-thPRC(2017)·9 citations
  5. 05

    Hyperon star in a modified quark meson coupling model

    R.N. Mishra🇮🇳 · H.S. Sahoo🇮🇳 · P.K. Panda🇮🇳 · N. Barik🇮🇳 · T. Frederico🇧🇷

    We determine the equation of state (EOS) of nuclear matter with the inclusion of hyperons in a self-consistent manner by using a Modified Quark Meson Coupling Model (MQMC) where the confining interaction for quarks inside a baryon is represented by a phenomenological average potential in an equally mixed scalar-vector harmonic form. The hadron-hadron interaction in nuclear matter is then realized by introducing additional quark couplings to , , and mesons through mean-field approximations. The effect of a nonlinear - term on the equation of state is studied. The hyperon couplings are fixed from the optical potential values and the mass-radius curve is determined satisfying the maximum mass constraint of ~M for neutron stars, as determined in recent measurements of the pulsar PSR J0348+0432. We also observe that there is no significant advantage of introducing the nonlinear - term in the context of obtaining the star mass constraint in the present set of parametrizations.

    nucl-thPRC(2016)·27 citations
  6. 06

    Isomerism in the "south-east" of Sn and a predicted neutron-decaying isomer in Pd

    Cenxi Yuan · Zhong Liu · Furong Xu · P. M. Walker · Zs. Podolyak · C. Xu · Z.Z. Ren · B. Ding · M.L. Liu · X.Y. Liu · H.S. Xu · X.H. Zhou · Y.H. Zhang · W. Zuo

    Excited states in neutron-rich nuclei located south-east of Sn are investigated by shell-model calculations. A new shell-model Hamiltonian is constructed for the present study. The proton-proton and neutron-neutron interactions of the Hamiltonian are obtained through the existing CD-Bonn matrix results, while the proton-neutron interaction across two major shells is derived from the monopole based universal interaction plus the M3Y spin-orbit force. The present Hamiltonian can reproduce well the experimental data available in this region, including one-neutron separation energies, level energies and the experimental values of isomers in Sn, Cd, and Pd. New isomers are predicted in this region, in Sn, Cd, Pd, In and Ag, in which almost no excited states are known experimentally yet. In the odd-odd In and Ag, the predicted very long life-times of the low-lying states are discussed, demanding more information on the related proton-neutron interaction. The low-lying states of In are discussed in connection with the recently observed rays. The predicted isomer in Pd could decay by both electromagnetic transitions and neutron emission with comparable partial life-times, making it a good candidate for neutron radioactivity, a decay mode which is yet to be discovered.

    nucl-thPLB(2016)·39 citations
  7. 07

    Do nuclear collisions create a locally equilibrated quark-gluon plasma?

    Paul Romatschke🇺🇸

    Experimental results on azimuthal correlations in high energy nuclear collisions (nucleus-nucleus, proton-nucleus and proton-proton) seem to be well described by viscous hydrodynamics. It is often argued that this agreement implies either local thermal equilibrium or at least local isotropy. In this note, I present arguments why this is not the case. Neither local near-equilibrium nor near-isotropy are required in order for hydrodynamics to offer a successful and accurate description of experimental results. However, I predict the breakdown of hydrodynamics at momenta of order seven times the temperature, corresponding to a smallest possible QCD liquid drop size of 0.15 fm.

    nucl-thhep-phnucl-exEPJC(2017)·138 citations

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first authorsco-authorsvia INSPIRE