22 research outputs found
Statistical and Dynamic Models of Charge Balance Functions
Charge balance functions, which identify balancing particle-antiparticle
pairs on a statistical basis, have been shown to be sensitive to whether
hadronization is delayed by several fm/c in relativistic heavy ion collisions.
Results from two classes of models are presented here, microscopic hadronic
models and thermal models. The microscopic models give results which are
contrary to recently published pi+pi- balance functions from the STAR
collaboration, whereas the thermal model roughly reproduce the experimental
results. This suggests that charge conservation is local at breakup, which is
in line with expectations for a delayed hadronization. Predictions are also
presented for balance functions binned as a function of Q_inv.Comment: 12 pages 6 figure
Thermal production of the meson in the channel
Recent measurements of the pi^+pi^- invariant mass distribution at RHIC show
a shifted peak for the rho meson in 100A GeV in peripheral Au + Au and even in
p + p collisions. A recent theoretical study based on a picture of in-medium
production rates of pions, showed that a large shift could result from a
combination of the Boltzmann factor and the collisional broadening of the rho.
Here we argue that the two-pion density of states is the appropriate quantity
if one assumes a sudden break-up of the system. Methods for calculating the
density of states which include Bose effects are derived. The resulting
invariant mass distributions are significantly enhanced at lower masses and the
rho peak is shifted downward by ~ 35 MeV.Comment: 10 pages, 4 figure