41 research outputs found
Investigating in-medium properties of the meson via the decay
We investigate the feasibility of studying in-medium properties of the
meson in photoproduction experiments via the decay
. We use the GiBUU transport model to compare
different methods of obtaining in-medium information, such as the invariant
mass spectrum, transparency ratio, excitation function and momentum spectrum.
We show that the final-state interaction of the pion poses a major obstacle for
the interpretation of the invariant mass spectrum. The other three observables
turn out to be fairly independent of final-state interactions and thus can give
access to the 's in-medium properties.Comment: 8 pages, 6 figure
Vector Meson Spectral Functions in a Coarse-Graining Approach
Dilepton production in heavy-ion collisions at top SPS energy is investigated
within a coarse-graining approach that combines an underlying microscopic
evolution of the nuclear reaction with the application of medium-modified
spectral functions. Extracting local energy and baryon density for a grid of
small space-time cells and going to each cell's rest frame enables to determine
local temperature and chemical potential by application of an equation of
state. This allows for the calculation of thermal dilepton emission. We apply
and compare two different spectral functions for the : A hadronic
many-body calculation and an approach that uses empirical scattering
amplitudes. Quantitatively good agreement of the model calculations with the
data from the NA60 collaboration is achieved for both spectral functions, but
in detail the hadronic many-body approach leads to a better description,
especially of the broadening around the pole mass of the and for the
low-mass excess. We further show that the presence of a pion chemical potential
significantly influences the dilepton yield.Comment: 9 pages, 2 figures; Contribution for proceedings of the Resonance
Workshop in Catania 201
Dilepton Production in Transport-based Approaches
We investigate dilepton production in transport-based approaches and show
that the baryon couplings of the meson represent the most important
ingredient for understanding the measured dilepton spectra. At low energies (of
a few GeV), the baryon resonances naturally play a larger role and affect
already the vacuum spectra via Dalitz-like contributions, which can be captured
well in an on-shell-transport scheme. At higher energies, the baryons mostly
affect the in-medium self energy of the , which is harder to tackle in
transport models and requires advanced techniques.Comment: 4 pages, 3 figures, PANIC 2014 proceeding
Particle production and equilibrium properties within a new hadron transport approach for heavy-ion collisions
The microscopic description of heavy-ion reactions at low beam energies is achieved within hadronic transport approaches. In this article a new approach called "Simulating Many Accelerated Strongly interacting Hadrons" (SMASH) is introduced and applied to study the production of nonstrange particles in heavy-ion reactions at Ekin=0.4A-2A GeV. First, the model is described including details about the collision criterion, the initial conditions and the resonance formation and decays. To validate the approach, equilibrium properties such as detailed balance are presented and the results are compared to experimental data for elementary cross sections. Finally results for pion and proton production in C+C and Au+Au collisions is confronted with data from the high-acceptance dielectron spectrometer (HADES) and FOPI. Predictions for particle production in π+A collisions are made