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Nuclear Theory·nucl-th

Thursday·August 18, 2016

9 papers—4 primary·5 cross-listed

All9Primary4Cross-lists5
  1. 05

    [Submitted on 16 Aug 2016] (cross-list from hep-ph)

    Revealing the source of the radial flow patterns in proton--proton collisions using hard probes

    Antonio Ortiz🇲🇽 · Gyula Bencédi🇲🇽 · Héctor Bello🇲🇽

    In this work, we propose a tool to reveal the origin of the collective-like phenomena observed in proton--proton collisions. We exploit the fundamental difference between the underlying mechanisms, color reconnection (CR) and hydrodynamics, which produce radial flow patterns in \textsc{Pythia}~8 and \textsc{Epos}~3, respectively. Specifically, we proceed by examining the strength of the coupling between the soft and hard components which, by construction, is larger in \textsc{Pythia}~8 than in \textsc{Epos}~3. We study the transverse momentum () distributions of charged pions, kaons and (anti)protons in inelastic pp collisions at 7\,TeV produced at mid-rapidity. Specific selections are made on an event-by-event basis as a function of the charged particle multiplicity and the transverse momentum of the leading jet () reconstructed using the \textsc{FastJet} algorithm at mid-pseudorapidity (). From our studies, quantitative and qualitative differences between \textsc{Pythia}~8 and \textsc{Epos}~3 are found in the spectra when (for a given multiplicity class) the leading jet is increased. In addition, we show that for low-multiplicity events the presence of jets can produce radial flow-like behavior. Motivated by our findings, we propose to perform a similar analysis using experimental data from RHIC and LHC.

    Comments:
    16 pages, 6 figures. The text was significantly modified and extended. One figure was removed whereas some were slightly modified. References were corrected and updated. The final version of this paper appears in Journal of Physics G (Nuclear and Particle Physics)
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1608.04784 [pdf]
    J.Phys.G(2017)·54 citations
  2. 06

    [Submitted on 16 Aug 2016] (cross-list from hep-lat)

    Neutrinoless double beta decay from lattice QCD

    Amy Nicholson🇺🇸 · Evan Berkowitz🇺🇸 · Chia Cheng Chang🇺🇸 · M. A. Clark🇺🇸 · Balint Joo🇺🇸 · Thorsten Kurth🇺🇸 · Enrico Rinaldi🇺🇸 · Brian Tiburzi🇺🇸 · Pavlos Vranas🇺🇸 · Andre Walker-Loud🇺🇸

    While the discovery of non-zero neutrino masses is one of the most important accomplishments by physicists in the past century, it is still unknown how and in what form these masses arise. Lepton number-violating neutrinoless double beta decay is a natural consequence of Majorana neutrinos and many BSM theories, and many experimental efforts are involved in the search for these processes. Understanding how neutrinoless double beta decay would manifest in nuclear environments is key for understanding any observed signals. In these proceedings we present an overview of a set of one- and two-body matrix elements relevant for experimental searches for neutrinoless double beta decay, describe the role of lattice QCD calculations, and present preliminary lattice QCD results.

    Comments:
    Plenary talk given at the 34th International Symposium on Lattice Field Theory, Southampton, UK, 24-30 July 2016
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1608.04793 [pdf]
    PoS(2016)·25 citations
  3. 07

    [Submitted on 17 Aug 2016] (cross-list from hep-ph)

    Generation of strong magnetic fields in dense quark matter driven by the electroweak interaction of quarks

    Maxim Dvornikov (IZMIRAN, Tomsk State University, University of Hamburg)🇷🇺

    We study the generation of strong large scale magnetic fields in dense quark matter. The magnetic field growth is owing to the magnetic field instability driven by the electroweak interaction of quarks. We discuss the situation when the chiral symmetry is unbroken in the degenerate quark matter. In this case we predict the amplification of the seed magnetic field to the strengths . In our analysis we use the typical parameters of the quark matter in the core of a hybrid star or in a quark star. We also discuss the application of the obtained results to describe the magnetic fields generation in magnetars.

    Comments:
    15 pages in pdflatex, 4 eps figures; minimal changes in the text, version to be published in Nucl.Phys.B
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1608.04946 [pdf]
    NPB(2016)·17 citations
  4. 08

    [Submitted on 17 Aug 2016] (cross-list from hep-ph)

    Relaxation of the chiral imbalance in dense matter of a neutron star

    Maxim Dvornikov (IZMIRAN, Tomsk State University, University of Hamburg)🇷🇺

    Using the quantum field theory methods, we calculate the helicity flip of an electron scattering off protons in dense matter of a neutron star. The influence of the electroweak interaction between electrons and background nucleons on the helicity flip is examined. We also derive the kinetic equation for the chiral imbalance. The derived kinetic equation is compared with the results obtained by other authors.

    Comments:
    8 pages in pdflatex, EPJ Web of Conferences latex style; contribution to proceedings of Quarks-2016
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1608.04950 [pdf]
    EPJ Web Conf.(2016)·0 citations
  5. 09

    [Submitted on 17 Aug 2016] (cross-list from astro-ph.HE)

    Role of medium modifications for neutrino-pair processes from nucleon-nucleon bremsstrahlung - Impact on the protoneutron star deleptonization

    Tobias Fischer🇵🇱

    In this article the neutrino-pair production from nucleon-nucleon (NN) bremsstrahlung is explored via medium-modifications of the strong interactions at the level of the one-pion exchange approximation. It governs the bulk part of the NN interaction at low densities relevant for the neutrino physics in core-collapse supernova studies. The resulting medium modified one-pion exchange rate for the neutrino-pair processes is implemented in simulations of core collapse supernovae in order to study the impact on the neutrino signal emitted from the deleptonization of the nascent proto-neutron star. Consequences for the nucleosynthesis of heavy elements of the material ejected from the PNS surface are discussed.

    Comments:
    9 pages, 7 figures, accepted for publication in Astronomy & Astrophysics
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1608.05004 [pdf]
    Astron.Astrophys.(2016)·52 citations

Affiliations

first authorsco-authorsvia INSPIRE