skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Exploring QCD dynamics in medium energy γA semiexclusive collisions

Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
OSTI Identifier:
Grant/Contract Number:
Resource Type:
Journal Article: Published Article
Journal Name:
Physics Letters. Section B
Additional Journal Information:
Journal Volume: 760; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-28 11:10:32; Journal ID: ISSN 0370-2693
Country of Publication:

Citation Formats

Larionov, A. B., and Strikman, M. Exploring QCD dynamics in medium energy γA semiexclusive collisions. Netherlands: N. p., 2016. Web. doi:10.1016/j.physletb.2016.07.067.
Larionov, A. B., & Strikman, M. Exploring QCD dynamics in medium energy γA semiexclusive collisions. Netherlands. doi:10.1016/j.physletb.2016.07.067.
Larionov, A. B., and Strikman, M. 2016. "Exploring QCD dynamics in medium energy γA semiexclusive collisions". Netherlands. doi:10.1016/j.physletb.2016.07.067.
title = {Exploring QCD dynamics in medium energy γA semiexclusive collisions},
author = {Larionov, A. B. and Strikman, M.},
abstractNote = {},
doi = {10.1016/j.physletb.2016.07.067},
journal = {Physics Letters. Section B},
number = C,
volume = 760,
place = {Netherlands},
year = 2016,
month = 9

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.physletb.2016.07.067

Citation Metrics:
Cited by: 2works
Citation information provided by
Web of Science

Save / Share:
  • The role of nonequilibrium and quantal effects in fast nucleus-nucleus collisions is studied via the Vlasov-Uehling-Uhlenbeck theory which includes the nuclear mean field dynamics, two-body collisions, and Pauli blocking. The intranuclear cascade model, where the dynamics is governed by independent NN collisions, and the Vlasov equation, where the nuclear mean field determines the collision dynamics, are also studied as reference cases. The Vlasov equation (no collision term) yields single particle distribution functions which--after the reaction--are only slightly modified in momentum space; even in central collisions, transparency is predicted. This is in agreement with the predictions of the quantal time-dependent Hartree-Fockmore » method. In contrast, large momentum transfer is obtained when the Uehling-Uhlenbeck collision term is incorporated; then the final momentum distribution is nearly spherically symmetric in the center of mass and a well-equilibrated nuclear system is formed: the nuclei stop each other; the translational kinetic energy is transformed into randomized microscopic motion. The Vlasov-Uehling-Uhlenbeck theory is supplemented with a phase space coalescence model of fragment formation. Calculated proton spectra compare well with recent data for Ar(42, 92, and 137 MeV/nucleon) + Ca. Also the total yields of medium mass fragments are well reproduced in the present approach. The mean field dynamics without two-body collisions, on the other hand, exhibits forward peaked proton distributions, in contrast to the data. The cascade approach underpredicts the yields of low energy protons by more than an order of magnitude.« less
  • Cited by 7
  • Whereas the three-body Coulomb problem for single excitation and ionization was claimed to be solved in a mathematically correct way during 1999 until 2004 for electron impact on hydrogen and helium, ion-impact ionization still represents a major challenge for theory. Troubling discrepancies have been observed recently in fully differential cross sections (FDCS) for helium single ionization by fast ion impact and even experimental total cross sections are in striking disagreement with the predictions of all state-of-the-art theories for low-energy antiproton collisions. Therefore, within the future Facility for Low-energy Antiproton and Ion Research (FLAIR), it has been proposed to combine state-of-the-artmore » many-particle imaging methods with a novel electrostatic storage ring for slow antiprotons in order to realize single and multiple ionization cross section measurements for antiprotons colliding with atoms, molecules and clusters. Total, as well as any differential cross sections up to FDCS including ionization-excitation reactions are envisaged to become available, serving as benchmark data for theory. Here, the present status of experiments in comparison with theory is presented and the layout of an Ultra-low energy Storage Ring (USR) with its integrated reaction microscope at FLAIR is described.« less
  • A Fourier-based method is presented to relate changes of the molecular structure during a molecular dynamics simulation with fluctuations in the electronic excitation energy. The method implies sampling of the ground state potential energy surface. Subsequently, the power spectrum of the velocities is compared with the power spectrum of the excitation energy computed using time-dependent density functional theory. Peaks in both spectra are compared, and motions exhibiting a linear or quadratic behavior can be distinguished. The quadratically active motions are mainly responsible for the changes in the excitation energy and hence cause shifts between the dynamic and static values ofmore » the spectral property. Moreover, information about the potential energy surface of various excited states can be obtained. The procedure is illustrated with three case studies. The first electronic excitation is explored in detail and dominant vibrational motions responsible for changes in the excitation energy are identified for ethylene, biphenyl, and hexamethylbenzene. The proposed method is also extended to other low-energy excitations. Finally, the vibrational fingerprint of the excitation energy of a more complex molecule, in particular the azo dye ethyl orange in a water environment, is analyzed.« less