Open heavy flavor and J/psi at RHIC and LHC

The suppression and collective flow of open and hidden heavy flavor in ultra-relativistic heavy ion collisions is studied with the partonic transport model Boltzmann Approach to MultiParton Scatterings (BAMPS). Charm and bottom quarks interact with the rest of the medium via elastic scatterings with an improved Debye screening and a running coupling. Heavy flavor electron data from RHIC can only be described if the cross section is multiplied with K=3.5 to mimic the contribution from radiative processes. With the same value for K we compare to elliptic flow data of D mesons at the LHC and find a good agreement. However, the nuclear modification factor of D mesons, non-prompt J/psi, muons, and electrons at the LHC is underestimated in our calculations. In addition, we present first BAMPS results on the suppression and elliptic flow of J/psi mesons, which are treated in the same framework.Comment: 4 pages, 3 figures, minor text modifications in version 2, Proceedings for Hard Probes 2012, Cagliari, Ital

An Analysis of the Economic Impact of Biodiesel Production in Illinois

The production of biodiesel in the United States has expanded greatly in recent years. A factor contributing to the growth of this industry is the perception that renewable fuel production is an economic boon to state and local economies, particularly those of rural areas. This study estimates the economic impact of biodiesel production in the state of Illinois. Through input-output analysis and by simulating the industry using IMPLAN, the impact of a 10 million gallon per year plant using soy oil as its only feedstock is modeled. The estimated effect on output, employment, and other parameters is substantial. However, the results also demonstrate that the magnitude and nature of this impact is heavily reliant on the feedstock used in production and that the choice of feedstock can limit the economic gains in rural localities

Collisional energy loss of heavy quarks

We develop a transport approach for heavy quarks in a quark-gluon plasma, which is based on improved binary collision rates taking into account quantum statistics, the running of the QCD coupling and an effective screening mass adjusted to hard-thermal loop calculations. We quantify the effects of in-medium collisions by calculating the heavy flavor nuclear modification factor and the elliptic flow for RHIC energies, which are comparable to radiative effects. We also derive an analytic formula for the mean collisional energy loss of an energetic heavy quark in a streaming quark gluon plasma.Comment: 7 pages, 8 figures, 1 tabl

Production and elliptic flow of heavy quarks at RHIC and LHC within a partonic transport model

Production and elliptic flow of heavy quarks are investigated in nucleus-nucleus collisions at RHIC and LHC within the Boltzmann Approach of MultiParton Scatterings (BAMPS). The initial heavy quark yield is estimated with the leading order mini-jet model and compared to PYTHIA for several parton distribution functions. Secondary production of heavy quarks in the quark-gluon plasma is examined within the full 3+1 dimensional BAMPS simulation of heavy ion collisions. At RHIC this yield is negligible, but for LHC charm production in the QGP plays a significant role. In addition, we study the elliptic flow of charm quarks at RHIC with the result that leading order processes are not sufficient to describe the experimental data.Comment: 8 pages, 5 figures, 2 tables, to appear in the proceedings of the 26th Winter Workshop on Nuclear Dynamic

Production, elliptic flow and energy loss of heavy quarks in the quark-gluon plasma

Production, elliptic flow and the nuclear modification factor of charm and bottom quarks are studied in central and non-central heavy-ion collisions at RHIC and LHC using the partonic transport model Boltzmann Approach of MultiParton Scatterings (BAMPS). Employing an initial heavy quark yield obtained with PYTHIA the full space-time evolution of charm and bottom quarks in the quark-gluon plasma (QGP) is carried out with BAMPS, taking also secondary production in the QGP into account. Only elastic collisions of heavy quarks with particles from the medium cannot describe the experimentally observed elliptic flow and nuclear modification factor. However, using an improved Debye screening and the running coupling yields a result which is much closer to data.Comment: 4 pages, 1 figure, to appear in the conference proceedings of Hot Quarks 2010, few minor modifications in 2nd versio

Der Philosoph der Freiheit wird Hundert : kann die Freiheit sich selbst zum Wert erheben? ; zum hundertsten Geburtstag Jean-Paul Sartres

Wie kaum ein anderer hat Sartre die Freiheit des Menschen betont und gegen die Zwangsvorstellung angeschrieben, der Mensch sei determiniert. Kann die Freiheit sich selbst zum Wert erheben? Zum hundertsten Geburtstag Jean-Paul Sartres sind dessen Entwürfe für eine Moralphilosophie auf Deutsch erschienen