PaperPanorama

Nuclear Theory·nucl-th

Monday·July 5, 2021

5 papers2 primary·3 cross-listed

  1. 03

    Shared Data and Algorithms for Deep Learning in Fundamental Physics

    Lisa Benato · Erik Buhmann · Martin Erdmann · Peter Fackeldey · Jonas Glombitza · Nikolai Hartmann · Gregor Kasieczka · William Korcari · Thomas Kuhr · Jan Steinheimer · Horst Stöcker · Tilman Plehn · Kai Zhou

    We introduce a Python package that provides simply and unified access to a collection of datasets from fundamental physics research - including particle physics, astroparticle physics, and hadron- and nuclear physics - for supervised machine learning studies. The datasets contain hadronic top quarks, cosmic-ray induced air showers, phase transitions in hadronic matter, and generator-level histories. While public datasets from multiple fundamental physics disciplines already exist, the common interface and provided reference models simplify future work on cross-disciplinary machine learning and transfer learning in fundamental physics. We discuss the design and structure and line out how additional datasets can be submitted for inclusion. As showcase application, we present a simple yet flexible graph-based neural network architecture that can easily be applied to a wide range of supervised learning tasks. We show that our approach reaches performance close to dedicated methods on all datasets. To simplify adaptation for various problems, we provide easy-to-follow instructions on how graph-based representations of data structures, relevant for fundamental physics, can be constructed and provide code implementations for several of them. Implementations are also provided for our proposed method and all reference algorithms.

    cs.LGastro-ph.IMhep-phnucl-th+2Comput.Softw.Big Sci.(2022)·19 citations
  2. 04

    Post-explosion evolution of core-collapse supernovae

    M. Witt · A. Psaltis · H. Yasin · C. Horn · M. Reichert · T. Kuroda · M. Obergaulinger · S. M. Couch · A. Arcones

    We investigate the post-explosion phase in core-collapse supernovae with 2D hydrodynamical simulations and a simple neutrino treatment. The latter allows us to perform 46 simulations and follow the evolution of the 32 successful explosions during several seconds. We present a broad study based on three progenitors (11.2 , 15 , and 27 ), different neutrino-heating efficiencies, and various rotation rates. We show that the first seconds after shock revival determine the final explosion energy, remnant mass, and properties of ejected matter. Our results suggest that a continued mass accretion increases the explosion energy even at late times. We link the late-time mass accretion to initial conditions such as rotation strength and shock deformation at explosion time. Only some of our simulations develop a neutrino-driven wind that survives for several seconds. This indicates that neutrino-driven winds are not a standard feature expected after every successful explosion. Even if our neutrino treatment is simple, we estimate the nucleosynthesis of the exploding models for the 15 progenitor after correcting the neutrino energies and luminosities to get a more realistic electron fraction.

    astro-ph.HEastro-ph.SRnucl-thApJ(2021)·27 citations
  3. 05

    X(3872) Production in Relativistic Heavy-Ion Collisions

    Baoyi Chen🇨🇳 · Liu Jiang🇨🇳 · Xiao-Hai Liu🇨🇳 · Yunpeng Liu🇨🇳 · Jiaxing Zhao🇨🇳

    Heavy-ion collisions provide a unique opportunity to study the nature of X(3872) compared with electron-positron and proton-proton (antiproton) collisions. We investigate the centrality and momentum dependence of X(3872) in heavy-ion collisions via the Langevin equation and instant coalescence model (LICM). When X(3872) is treated as a compact tetraquark state, the tetraquarks are produced via the coalescence of heavy and light quarks near the quantum chromodynamic (QCD) phase transition due to the restoration of the heavy quark potential at . In the molecular scenario, loosely bound X(3872) is produced via the coalescence of - mesons in a hadronic medium after kinetic freeze-out. We employ the LICM to explain both and production as a benchmark. Then we give predictions regarding X(3872) production and the nuclear modification factor . We find that the total yield of tetraquark is several times larger than the molecular production in Pb-Pb collisions. Although the geometric size of the molecule is huge, the coalescence probability is small due to strict constraints on the relative momentum between and in the molecular Wigner function, which significantly suppresses the molecular yield.

    hep-phnucl-thPRC(2022)·44 citations

Affiliations

first authorsco-authorsvia INSPIRE