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Nuclear Theory·nucl-th

Wednesday·January 4, 2017

6 papers—2 primary·4 cross-listed

All6Primary2Cross-lists4
  1. 01

    [Submitted on 2 Jan 2017]

    Comprehensive analysis of large yields observed in Li induced reactions

    Jin Lei🇪🇸 · Antonio M. Moro🇪🇸

    Background: Large yields have been reported over the years in reactions with Li and Li projectiles. Previous theoretical analyses have shown that the elastic breakup (EBU) mechanism (i.e., projectile breakup leaving the target in its ground state) is able to account only for a small fraction of the total inclusive breakup cross sections, pointing toward the dominance of non-elastic breakup (NEB) mechanisms. Purpose: We aim to provide a systematic study of the inclusive cross sections observed in nuclear reactions induced by Li projectiles. In addition to estimating the total singles cross sections, it is our goal to evaluate angular and energy distributions of these particles and compare with experimental data, when available. Method: We compute separately the EBU and NEB components of the inclusive breakup cross sections. For the former, we use the continuum-discretized coupled-channels (CDCC) method, which treats this mechanism to all orders. For the NEB part, we employ the the model proposed in the eighties by Ichimura, Austern and Vincent [Phys. Rev. C32, 432 (1982)], within the DWBA approximation. Results: Overall, the sum of the computed EBU and NEB cross sections is found to reproduce very well the measured singles cross sections. In all cases analyzed, we find that the inclusive breakup cross section is largely dominated by the NEB component. Conclusions: The presented method provides a global and systematic description of inclusive breakup reactions induced by Li projectiles. It provides also a natural explanation of the previously observed underestimation of the measured yields by CDCC calculations. The method used here can be extended to other weakly-bound projectiles, including halo nuclei.

    Comments:
    11 pages, 16 figures, fig. 12 updated; some typos corrected
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1701.00547 [pdf]
    PRC(2017)·53 citations
  2. 02

    [Submitted on 3 Jan 2017]

    Structure effects on fission yields

    Bharat Kumar · M.T. Senthil kannan · M. Balasubramaniam · B. K. Agrawal · S. K. Patra

    The structure effects of the fission fragments on their yields are studied within the statical theory with the inputs, like, excitation energies and level density parameters for the fission fragments at a given temperature calculated using the temperature dependent relativistic mean field formalism (TRMF). For the comparison, the results are also obtained using the finite range droplet model. At temperatures MeV, the structural effects of the fission fragments influence their yields. It is also seen that at 3 MeV, the fragments become spherical and the fragments distribution peaks at a close shell or near close shell nucleus.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1701.00731 [pdf]
    2 citations
  3. 03

    [Submitted on 2 Jan 2017] (cross-list from hep-ph)

    DPS in CGC: HBT correlations in double inclusive photon production

    Alex Kovner🇺🇸 · Amir H. Rezaeian🇨🇱

    We introduce a technique to study double parton scattering (DPS) in the Color-Glass-Condensate (CGC) approach. We show that the cross-section of the DPS in the CGC approach is calculable in terms of new nonperturbative objects, generalized double transverse momentum-dependent parton distribution (2GTMD) functions. We investigate the production of pairs of prompt photons from two partons in the projectile hadron in high-energy proton-nucleus collisions. We show that even for independent partons in the projectile, the prompt photon correlation function exhibits Hanbury Brown and Twiss (HBT) correlations. The width of the HBT peak is controlled by the transverse distance between the parton of the pair, which is of the order of the proton size. Thus, the HBT measurements in two-particle production such as prompt photon pairs provide useful information about the nonperturbative 2GTMDs.

    Comments:
    14 pages, 3 figures; v2: results unchanged, notation clarified and corrected, references added. The version to appear in PRD
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    1701.00494 [pdf]
    PRD(2017)·12 citations
  4. 04

    [Submitted on 3 Jan 2017] (cross-list from nucl-ex)

    Effects of mean-field and the softening of equation of state on elliptic flow in Au+Au collision at = 5 GeV from JAM model

    Jiamin Chen🇨🇳 · Xiaofeng Luo🇺🇸 · Feng Liu🇨🇳 · Yasushi Nara🇯🇵

    We perform a systematic study of elliptic flow () in Au+Au collision at GeV by using a microscopic transport model JAM. The centrality, pseudorapidity, transverse momentum and beam energy dependence of for charged as well as identified hadrons are studied. We investigate the effects of both the hadronic mean-field and the softening of equation of state (EoS) on elliptic flow. The softening of EoS is realized by imposing attractive orbits in two body scattering, which can reduce the pressure of the system. We found that the softening of EoS leads to the enhancement of , while the hadronic mean-field suppresses relative to the cascade mode. It indicates that elliptic flow at high baryon density regions is highly sensitive to the EoS and the enhancement of may probe the signature of a first-order phase transition in heavy-ion collisions at beam energies of a strong baryon stopping region.

    Comments:
    7 pages, 9 figures, to appear in Chinese Physics C
    Subjects:
    Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    1701.00574 [pdf]
    CPC(2018)·7 citations
  5. 05

    [Submitted on 3 Jan 2017] (cross-list from hep-ph)

    Bottomonia suppression in an anisotropic quark-gluon plasma

    Radoslaw Ryblewski🇵🇱

    A brief review of recent studies on suppression of bottomonia in an anisotropic quark-gluon plasma created in heavy-ion collisions at the LHC is presented. A reasonable agreement between the model predictions for the inclusive suppression factor and the preliminary CMS experimental data is found. The values of the shear viscosity to the entropy density ratio extracted from the comparison with the data lie between one and two times the gauge/gravity duality lower bound. These values agree very well with the fluid dynamical fits to the light hadron correlation data and confirm that the quark-gluon plasma is a nearly-perfect fluid.

    Comments:
    Talk presented by Radoslaw Ryblewski at XII International Conference "Quark Confinement and the Hadron Spectrum", 29 Aug. - 3 Sept. 2015, Thessaloniki, Greece; 8 pages, 3 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1701.00644 [pdf]
    EPJ Web Conf.(2017)·0 citations
  6. 06

    [Submitted on 3 Jan 2017] (cross-list from hep-th)

    A Complete Diagrammatic Implementation of the Kinoshita-Lee-Nauenberg Theorem at Next-to-Leading Order

    Abdullah Khalil🇿🇦 · W. A. Horowitz🇿🇦

    We show for the first time in over 50 years how to correctly apply the Kinoshita-Lee-Nauenberg theorem diagrammatically in a next-to-leading order scattering process. We improve on previous works by including all initial and final state soft radiative processes, including absorption and an infinite sum of partially disconnected amplitudes. Crucially, we exploit the Monotone Convergence Theorem to prove that our delicate rearrangement of this formally divergent series is correct. This rearrangement yields a factorization of the infinite contribution from the initial state soft photons that then cancels in the physically observable cross section. We derive the first complete next-to-leading order, high-energy Rutherford elastic scattering cross section in the renormalization scheme as an explicit example of our procedure.

    Comments:
    5 pages, 2 figures
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1701.00763 [pdf]
    4 citations

Affiliations

first authorsco-authorsvia INSPIRE