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Nuclear Theory·nucl-th

Friday·July 3, 2015

7 papers—6 primary·1 cross-listed

All7Primary6Cross-lists1
  1. 01

    Grand canonical potential of a magnetized neutron gas

    Jacobus P.W. Diener · Frederik G. Scholtz

    We compute the effective action for stationary and spatially constant magnetic fields, when coupled anomalously to charge neutral fermions, by integrating out the fermions. From this the grand canonical partition function and potential of the fermions and fields are computed. This also takes care of magnetic field dependent vacuum corrections to the grand canonical potential. Possible applications to neutron stars are indicated.

    nucl-th1 citation
  2. 02

    Unnatural-parity (p,p') reactions in a factorized impulse-approximation model for polarization transfer and spin responses

    A. V. Plavko · M. S. Onegin · V. I. Kudriashov

    Linear combinations of the complete polarization-transfer observables, Dij, in the (p,p') reaction at intermediate energies are demonstrated. A comparison between systematized measured and calculated values of the combinations for the (T = 0 and T = 1) levels in C, for the (T = 0 and T = 1) states in O, and for the (T = 0 and T = 1) levels in Si are reported. Particularities in angular distributions of transverse- and longitudinal-spin-transfer probabilities, , for the T = 0 and T = 1 unnatural-parity states in the indicated nuclei are discussed. The spin-observable combinations Dls allowed to differentiate reliably the strength of the isoscalar and isovector spin-orbit interactions. The comparison of experimental and calculated with the use of zero-range treatment (LEA code) and exact finite-range calculations (DWBA-91 program) made it possible to identify the role of exchange contributions.

    nucl-th0 citations
  3. 03

    Flow anisotropies due to momentum deposition from hard partons

    Boris Tomasik🇸🇰 · Martin Schulc🇸🇰

    In nuclear collisions at the LHC large number of hard partons are created in initial partonic interactions, so that it is reasonable to suppose that they do not thermalise immediately but deposit their energy and momentum later into the evolving hot quark-gluon fluid. We show that this mechanism leads to contribution to flow anisotropies at all orders which are non-negligible and should be taken into account in realistic simulations.

    nucl-thActa Phys.Polon.Supp.(2015)·0 citations
  4. 04

    A study of charm quark correlations in ultra-relativistic + collisions with PYTHIA

    Shusu Shi🇨🇳 · Xin Dong🇺🇸 · Mustafa Mustafa🇺🇸

    Measurements of heavy flavor quark (charm and bottom) correlations in heavy ion collisions are instrumental to understand the flavor dependence of energy loss mechanisms in hot and dense QCD media. Experimental measurements of these correlations in baseline + collisions are crucial to understand the contributions of perturbative and non-perturbative QCD processes to the correlation functions and further help in interpreting correlation measurements in heavy ion collisions. In this paper, we investigate - meson correlations and with one particle from meson decay daughter correlations using PYTHIA Event Generator in + collisions at = 200, 500 and 5500 GeV. Charm/bottom events are found to contribute mainly to the away side/near side pattern of -electron correlations, respectively. In the energy region of RHIC, - correlations inherit initial - correlations and decay contribution is insignificant. Furthermore, Bottom quark correlations are suggested to be applicable at LHC energy, as the bottom contributions on related correlations are relatively large.

    nucl-th9 citations
  5. 05

    The Skyrme Tensor Force in Heavy Ion Collisions

    P. D. Stevenson · E. B. Suckling · S. Fracasso · M. C. Barton · A. S. Umar

    Background: [elided for arXiv character count] Purpose: With the advancement of computational power it is now possible to undertake TDHF calculations without any symmetry assumptions and incorporate the major strides made by the nuclear structure community in improving the energy density functionals used in these calculations. In particular, time-odd and tensor terms in these functionals are naturally present during the dynamical evolution, while being absent or minimally important for most static calculations. The parameters of these terms are determined by the requirement of Galilean invariance or local gauge invariance but their significance for the reaction dynamics have not been fully studied. This work addresses this question with emphasis on the tensor force. Method: The full version of the Skyrme force, including terms arising only from the Skyrme tensor force, is applied to the study of collisions within a completely symmetry-unrestricted TDHF implementation. Results: We examine the effect on fusion thresholds with and without the tensor force terms and find an effect on the fusion threshold energy of the order several MeV. Details of the distribution of the energy within terms in the energy density functional is also discussed. Conclusions: Terms in the energy density functional linked to the tensor force can play a non-negligible role in dynamic processes in nuclei, including those in which the terms do not affect ground state properties.

    nucl-thPRC(2016)·38 citations
  6. 06

    Ab Initio Derivation of Model Energy Density Functionals

    J. Dobaczewski

    I propose a simple and manageable method that allows for deriving coupling constants of model energy density functionals (EDFs) directly from ab initio calculations performed for finite fermion systems. A proof-of-principle application allows for linking properties of finite nuclei, determined by using the nuclear nonlocal Gogny functional, to the coupling constants of the quasilocal Skyrme functional. The method does not rely on properties of infinite fermion systems but on the ab initio calculations in finite systems. It also allows for quantifying merits of different model EDFs in describing the ab initio results.

    nucl-thJ.Phys.G(2016)·24 citations
  7. 07

    Effects of scalar mesons in a Skyrme model with hidden local symmetry

    Bing-Ran He🇯🇵 · Yong-Liang Ma🇨🇳 · Masayasu Harada🇯🇵

    We study the effects of light scalar mesons on the skyrmion properties by constructing and examining a mesonic model including pion, rho meson, and omega meson fields as well as two-quark and four-quark scalar meson fields. In our model, the physical scalar mesons are defined as mixing states of the two- and four-quark fields. We first omit the four-quark scalar meson field from the model and find that when there is no direct coupling between the two-quark scalar meson and the vector mesons, the soliton mass is smaller and the soliton size is larger for lighter scalar mesons; when direct coupling is switched on, as the coupling strength increases, the soliton becomes heavy, and the radius of the baryon number density becomes large, as the repulsive force arising from the meson becomes strong. We then include the four-quark scalar meson field in the model and find that mixing between the two-quark and four-quark components of the scalar meson fields also affects the properties of the soliton. When the two-quark component of the lighter scalar meson is increased, the soliton mass decreases and the soliton size increases.

    ↳ hep-phnucl-thPRD(2015)·10 citations

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first authorsco-authorsvia INSPIRE