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Nuclear Theory·nucl-th

Monday·May 18, 2015

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 01

    [Submitted on 14 May 2015]

    Pomeranchuk instability and Bose condensation of scalar quanta in a Fermi liquid

    E. E. Kolomeitsev🇸🇰 · D. N. Voskresensky🇷🇺

    We study excitations in a normal Fermi liquid with a local scalar interaction. Spectrum of bosonic scalar-mode excitations is investigated for various values and momentum dependence of the scalar Landau parameter in the particle-hole channel. For the conditions are found when the phase velocity on the spectrum of the zero sound acquires a minimum at a non-zero momentum. For there are only damped excitations, and for the spectrum becomes unstable against a growth of scalar-mode excitations (a Pomeranchuk instability). An effective Lagrangian for the scalar excitation modes is derived after performing a bosonization procedure. We demonstrate that the Pomeranchuk instability may be tamed by the formation of a static Bose condensate of the scalar modes. The condensation may occur in a homogeneous or inhomogeneous state relying on the momentum dependence of the scalar Landau parameter. Then we consider a possibility of the condensation of the zero-sound-like excitations in a state with a non-zero momentum in Fermi liquids moving with overcritical velocities, provided an appropriate momentum dependence of the Landau parameter .

    Comments:
    12 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas)
    arXiv:
    1505.03884 [pdf]
    1 citation
  2. 02

    [Submitted on 15 May 2015]

    Structures in 9Be, 10Be and 10B studied with tensor-optimized shell model

    Takayuki Myo · Atsushi Umeya · Hiroshi Toki · Kiyomi Ikeda

    We investigate the structures of Be and B with the tensor-optimized shell model (TOSM) using the effective interaction based on the bare nucleon-nucleon interaction AV8. The tensor correlation is treated in TOSM with the full optimization of 2p2h configurations including high-momentum components. The short-range correlation is described in the unitary correlation operator method (UCOM). It is found that the level orders of the low-lying states of Be and B are entirely reproduced. For Be, ground band states are located relatively in higher energy than the experiments, which indicates the missing clustering correlation in these states as seen in the case of Be with TOSM. In addition, the tensor force gives the larger attraction for =1/2 states than for =3/2 ones for Be. For Be, the tensor contribution of shows the largest value among the states. This can be related to the clustering correlation in this state. It is also found that the level order of three nuclei depends on the tensor force in comparison with the results obtained with the Minnesota interaction without the tensor force.

    Comments:
    12 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1505.03942 [pdf]
    PTEP(2015)·8 citations
  3. 03

    [Submitted on 15 May 2015]

    New Theoretical Results on Event-by-Event Fluctuations

    Mark I. Gorenstein🇺🇦

    Several theoretical results concerning event-by-event fluctuations are discussed: (1) a role of the global conservation laws and concept of statistical ensembles; (2) strongly intensive measures are introduced; they give a possibility to study e-by-e fluctuations for physical systems with volume fluctuations; (3) identity method for chemical fluctuations in a case of incomplete particle identification; (4) the example of particle number fluctuations in a vicinity of the critical point.

    Comments:
    invited talk at the CPOD 2014 conference, 25 pages
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1505.04135 [pdf]
    PoS(2015)·9 citations
  4. 04

    [Submitted on 15 May 2015] (cross-list from physics.atom-ph)

    Momentum-space calculation of He triatomic system with realistic potential

    A. Deltuva🇱🇹

    The system of three atoms with realistic interactions is studied in the momentum-space framework. It is demonstrated that short and long-range difficulties encountered in the coordinate-space calculations can be reliably resolved in the momentum-space calculations. Well-converged and accurate results are obtained for the ground and excited trimer energies, atom-dimer scattering length, phase shifts, inelasticity parameters, and elastic and breakup cross sections. A significant correction to previously published results is found for the elastic cross section at very low energy.

    Comments:
    8 pages, 4 figures, accepted for publication in Few-Body Systems
    Subjects:
    Atomic Physics (physics.atom-ph); Nuclear Theory (nucl-th)
    arXiv:
    1505.03927 [pdf]
    Few Body Syst.(2015)·19 citations
  5. 05

    [Submitted on 15 May 2015] (cross-list from hep-ph)

    Dilepton production from the quark-gluon plasma using leading-order (3+1)D anisotropic hydrodynamics

    Radoslaw Ryblewski🇵🇱 · Michael Strickland🇺🇸

    Dilepton production from the quark-gluon plasma (QGP) phase of ultra-relativistic heavy-ion collisions is computed using the leading-order (3+1)-dimensional anisotropic hydrodynamics. It is shown that high-energy dilepton spectrum is sensitive to the initial local-rest-frame momentum-space anisotropy of the QGP. Our findings suggest that it may be possible to constrain the early-time momentum-space anisotropy in relativistic heavy-ion collisions using high-energy dilepton yields.

    Comments:
    Talk presented by Radoslaw Ryblewski at Excited QCD 2015, 8-14 March 2015, Tatranska Lomnica, Slovakia, 6 pages, 2 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1505.04018 [pdf]
    Acta Phys.Polon.Supp.(2015)·3 citations
  6. 06

    [Submitted on 15 May 2015] (cross-list from hep-ph)

    A short review of some double-parton scattering processes

    Antoni Szczurek🇵🇱

    A few examples of quickly developing field of double parton scattering are discussed. We present arguments that the production of two pairs of charm quark-antiquark is the golden reaction to study the double parton scattering effects. We discuss briefly also mechanism of single parton scattering and show that it gives much smaller contribution to the final state. In this context we discuss also the contribution of perturbative parton-splitting mechanism which should also be added to the conventional DPS mechanism. The presence of the letter leads to collision energy and other kinematical variables dependence of so-called . We briefly discuss production of four jets. We concentrate on estimation of the contribution of DPS for jets widely separated in rapidity. Finally we briefly mention about DPS effects in production of .

    Comments:
    10 pages, 9 figures, invited talk at the Excited QCD 2015, Tatranska Lomnica, Slovakia, 8-14 March 2015. arXiv admin note: text overlap with arXiv:1504.06491, order of figures changed, references added
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1505.04067 [pdf]
    Acta Phys.Polon.Supp.(2015)·8 citations
  7. 07

    [Submitted on 15 May 2015] (cross-list from hep-ph)

    Manifestation of proton structure in the initial-state anisotropies in high-energy proton-proton collisions

    Patryk Kubiczek🇵🇱 · Stanislaw D. Glazek🇵🇱

    Ridge-like correlations in high-energy proton-proton collisions reported by the CMS collaboration suggest a collective flow that resembles the one in heavy-ion collisions. If the hydrodynamic description is valid then the effect results from the initial anisotropy of the colliding matter which depends on the structure of protons. Following recent theoretical developments, we propose several phenomenological models of the proton structure and calculate the anisotropy coefficients using the Monte Carlo Glauber model. Our estimates suggest that the event multiplicity dependence allows one to discriminate between different proton models.

    Comments:
    15 pages, 7 figures, submitted to Lith. J. Phys, corrected plots
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1505.04155 [pdf]
    Lith.J.Phys.(2015)·11 citations

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first authorsco-authorsvia INSPIRE