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Nuclear Theory·nucl-th

Thursday·January 31, 2019

6 papers—2 primary·4 cross-listed

All6Primary2Cross-lists4
  1. 03

    [Submitted on 29 Jan 2019] (cross-list from hep-th)

    Constructing phase space distributions with internal symmetries

    Niklas Mueller🇺🇸 · Raju Venugopalan🇺🇸

    We discuss an ab initio world-line approach to constructing phase space distributions in systems with internal symmetries. Starting from the Schwinger-Keldysh real time path integral in quantum field theory, we derive the most general extension of the Wigner phase space distribution to include color and spin degrees of freedom in terms of dynamical Grassmann variables. The corresponding Liouville distribution for colored particles, which obey Wong's equation, has only singlet and octet components, while higher moments are fully constrained by the Grassmann algebra. The extension of phase space dynamics to spin is represented by a generalization of the Pauli-Lubanski vector; its time evolution via the Bargmann-Michel-Telegdi equation also follows from the phase space trajectories of the underlying Grassmann coordinates. Our results for the Liouville phase space distribution in systems with both spin and color are of interest in fields as diverse as chiral fluids, finite temperature field theory and polarized parton distribution functions. We also comment on the role of the chiral anomaly in the phase space dynamics of spinning particles.

    Comments:
    13 pages, references added, typo corrected, accepted for publication in Phys. Rev. D
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1901.10492 [pdf]
    PRD(2019)·47 citations
  2. 04

    [Submitted on 29 Jan 2019] (cross-list from hep-ph)

    Initial state description of azimuthally collimated long range correlations in ultrarelativistic light-heavy ion collisions

    Mark Mace🇫🇮 · Vladimir V. Skokov🇺🇸 · Prithwish Tribedy🇺🇸 · Raju Venugopalan🇺🇸

    It was argued in arXiv:1805.09342 and arXiv:1807.00825 that the systematics of the azimuthal anisotropy coefficients measured in ultrarelativistic light-heavy ion collisions at RHIC and the LHC can be described in an initial state dilute-dense Color Glass Condensate (CGC) framework. We elaborate here on the discussion in these papers and provide further novel results that strengthen their conclusions. The underlying mathematical framework and numerical techniques employed are very similar to those in the CGC based IP-Glasma model used previously as initial conditions for heavy-ion collisions. The uncertainties in theory/data comparisons for small systems are discussed, with unknowns that are specific to the model distinguished from those that are generic to all models. We present analytical arguments that demonstrate that quantum interference effects such as Bose enhancement and Hanbury-Brown-Twiss correlations of gluons, as well as coherent multiple scattering of gluons in the projectile off color domains in the target, are enhanced in rare events. The quantum origins of the large anisotropies in small systems are corroborated by numerical results for deuteron-gold collisions that show that large anisotropies in rare configurations can occur when the nucleons in the projectile overlap significantly. This is at variance with the classical intuition of hydrodynamical models. We also comment on the consequences of ignoring the many-body color charge correlations of gluons in models that only consider geometrical fluctuations in the energy density.

    Comments:
    25 pages, 13 figures, 1 appendix
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1901.10506 [pdf]
    6 citations
  3. 05

    [Submitted on 30 Jan 2019] (cross-list from nucl-ex)

    Studies of the Three-Body Breakup in Deuteron-Deuteron Collisions near the Quasi-Free Limit at 160 MeV

    I. Ciepał · G. Khatri · K. Bodek · A. Deltuva · A. C. Fonseca · N. Kalantar-Nayestanaki · St. Kistryn · B. Kłos · A. Kozela · J. Kuboś · P. Kulessa · A. Łobejko and 11 other authors

    A set of differential cross section of the three-body H(,) breakup reaction at 160 MeV deuteron beam energy are presented for 147 kinematically complete configurations near the quasi-free scattering kinematics. The experiment was performed at KVI in Groningen, the Netherlands using the BINA detector. The cross-section data have been normalized to the H(,)H elastic scattering cross section. The data are compared to the recent single-scattering approximation (SSA) calculations for three-cluster breakup in deuteron-deuteron collisions. Confronting the SSA predictions with the experimental data shows that SSA provides the correct order of magnitude of the cross-section data. The studied energy is probably too low to meet the SSA assumptions which prevents better accuracy of the description.

    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1901.10737 [pdf]
    PRC(2019)·13 citations
  4. 06

    [Submitted on 30 Jan 2019] (cross-list from hep-ph)

    Future heavy-ion facilities: FCC-AA

    A. Dainese🇮🇹 · L. Apolinario🇵🇹 · N. Armesto🇪🇸 · D. d'Enterria🇨🇭 · J.M. Jowett🇨🇭 · J.-P. Lansberg🇫🇷 · J.G. Milhano🇵🇹 · C.A. Salgado🇪🇸 · M. Schaumann🇨🇭 · M. van Leuween🇳🇱 · U.A. Wiedemann🇨🇭

    The operation of the Future Circular Collider (FCC) with heavy ions would provide Pb-Pb and p-Pb collisions at sqrt{s_NN}= 39 and 63 TeV, respectively, per nucleon-nucleon collision, with projected per-month integrated luminosities of up to 110/nb and 29/pb, respectively. This document outlines the unique and broad physics opportunities with heavy ions at the energy frontier opened by FCC.

    Comments:
    14 pages, 8 figures, Proceedings of the Hard Probes 2018 International Conference, largely similar to the HI contribution to the FCC CDR Volume 1 http://cds.cern.ch/record/2651294
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1901.10952 [pdf]
    PoS(2019)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE