7,083 research outputs found
Dilepton production in proton-proton collisions at top RHIC energy
We study dielectron production in proton-proton collisions at top RHIC beam
energy within an extended statistical hadronization model. The invariant mass
spectrum of correlated dielectron pairs is evaluated in the low invariant mass
region and calculated results are compared with the PHENIX experiment. The
model is found to be able to describe the data very well up to invariant masses
of 1 GeV with few adjustable parameters.Comment: Proceedings of Hot Quarks 201
Fractional Periodicity of Persistent Currents: A Signature of Broken Internal Symmetry
We show from the symmetries of the many body Hamiltonian, cast into the form
of the Heisenberg (spin) Hamiltonian, that the fractional periodicities of
persistent currents are due to the breakdown of internal symmetry and the spin
Hamiltonian holds the explanation to this transition. Numerical
diagonalizations are performed to show this explicitely. Persistent currents
therefore, provide an easy way to experimentally verify broken internal
symmetry in electronic systems.Comment: minor correction
Dilepton production in p+p, Cu+Cu and Au+Au collisions at 200 AGeV
We study dilepton production in proton-proton, Cu+Cu as well as in Au+Au
collisions at the center-of-mass energy 200 GeV per participating nucleon pair
within an extended statistical hadronization model. In extension to earlier
studies we incorporate transport calculations for an estimate of uncorrelated
e+e- -pairs from semileptonic D meson decays. While the invariant mass spectrum
of dielectrons is well understood in the p+p collisions, severe discrepancies
among different model scenarios based on hadronic degrees of freedom and recent
data from the PHENIX Collaboration are found in heavy-ion collisions in the low
mass region from 0.15 to 0.6 GeV as well as in the intermediate mass regime
from 1.1 to 3 GeV when employing the standard dilepton sources. We investigate,
furthermore, the background from correlated dileptons that are not emitted as a
pair from a parent hadron but emerge from semileptonic decays of two correlated
daughter hadrons. Our calculations suggest a sizeable contribution of such
sources in central heavy-ion collisions in the low mass region. However, even
the upper limits of our calculations are found to be far below the dilepton
mass spectra of the PHENIX Collaboration.Comment: revised version, 17 pages, 13 figure
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