PaperPanorama

Nuclear Theory·nucl-th

Monday·October 31, 2016

10 papers8 primary·2 cross-listed

  1. 09

    [Submitted on 25 Oct 2016] (cross-list from hep-ph)

    Unexpected properties of interactions of high energy protons

    I.M. Dremin🇷🇺

    Experimental data on proton-proton interactions in high energy collisions show quite a special and unexpected behaviour of the proportion of elastic scattering compared to inelastic processes with increasing energy. It decreases at the beginning (at comparatively low energies) but then starts increasing. From Intersecting Storage Rings (ISR) energies of 23.5 - 62.5 GeV up to higher energies 7 - 13 TeV at the Large Hadron Collider (LHC) it increases by a factor more than 1.5! According to intuitive classical ideas we would expect a stable tendency with increasing proportion of the break-down of protons compared to their survival probability. One can assume that either the asymptotic freedom or the extremely short time of flight of high energy protons through each other are in charge of such a surprising effect. The unquestionable principle of unitarity combined with the available experimental data on elastic scattering is used to get new conclusions about the shape of the interaction region of colliding protons. Its evolution at present energies is considered. Some predictions about its behaviour at even higher energies are described with different assumptions on relative roles of elastic scattering and inelastic processes. The shape can transform rather drastically if the proportion of elastic processes keeps rising. This unexpected property leads to an unexpected corollary. The possible origin of the effect and its interrelation to the strong interaction dynamics are speculated.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1610.07937 [pdf]
    Phys.Usp.(2017)·22 citations
  2. 10

    [Submitted on 27 Oct 2016] (cross-list from hep-th)

    Coupling constant corrections in a holographic model of heavy ion collisions

    Sašo Grozdanov🇳🇱 · Wilke van der Schee🇺🇸

    We initiate a holographic study of coupling-dependent heavy ion collisions by analysing for the first time the effects of leading-order, inverse coupling constant corrections. In the dual description, this amounts to colliding gravitational shock waves in a theory with curvature-squared terms. We find that at intermediate coupling, nuclei experience less stopping and have more energy deposited near the lightcone. When the decreased coupling results in an 80% larger shear viscosity, the time at which hydrodynamics becomes a good description of the plasma created from high energy collisions increases by 25%. The hydrodynamic phase of the evolution starts with a wider rapidity profile and smaller entropy.

    Comments:
    V2: 6 pages, 5 figures. Second-order coupling constant corrections added. Version appeared in PRL
    Subjects:
    High Energy Physics — Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1610.08976 [pdf]
    PRL(2017)·61 citations

Affiliations

first authorsco-authorsvia INSPIRE