arXiv subjects
Publications and source records attributed to Petr Chaloupka.
An update on femtoscopic pi-Xi correlations in Au+Au collisions as measured by the STAR experiment at RHIC is presented. Centrality dependence of Gaussian radii and relative emission asymmetry is extracted for the first time.
High Energy Nuclear Physics (HENP) collaborations' experience show that the computing resources available at a single site are often neither sufficient nor satisfy the need of remote collaborators. From latencies in the network connectivity to the lack of interactivity, work at distant computing centers is often inefficient. Having fully functional software stack on local resources is a strong enabler of science opportunities for any local group who can afford the time investment. Prague's heavy-ions group participating in STAR experiment at RHIC has been a strong advocate of local computing as the most efficient means of data processing and physics analyses. Tier 2 computing center was set up at a Regional Computing Center for Particle Physics called "Golias". We report on our experience in setting up a fully functional Tier 2 center and discuss the solutions chosen to address storage space and analysis issues and the impact on the farms overall functionality. This includes a locally built STAR analysis framework, integration with a local DPM system (a cost effective storage solution), the influence of the availability and quality of the network connection to Tier 0 via a dedicated CESNET/ESnet link and the development of light-weight yet fully automated data transfer tools allowing the movement of entire datasets from BNL (Tier 0) to Golias (Tier 2).
Qualitative comparison of source sizes from pi-Xi correlations analyses in d+Au and Au+Au collisions at sqrt(s_NN)=200G GeV and sqrt(s_NN)=62 GeV is presented. For the most central Au+Au collisions at sqrt(s_NN)=200 GeV we report first quantitative results concerning size of the pi-Xi source and relative shift of the average emission points between pi and Xi showing that the homogeneity region of Xi source is smaller then that of pion and significantly shifted in the transverse direction.
We report on STAR analyses of p-lambda, p_bar-lambda_bar, p-lambda_bar, p_bar-lambda, p-p_bar and pi-Xi correlations in Au+Au collisions at sqrt(S_NN)=62 and 200 GeV. Measured source sizes in p(p_bar)-lambda(lambda_bar) and p-p_bar are shown to be in qualitative agreement with flow expectations. Interaction potential between p-lambda_bar, p_bar-lambda was investigated by measuring scattering length, thus showing that correlation analyses in heavy-ion collisions can be used to study strong interaction potential between hadrons. We present also analyses of pi-Xi correlations addressing independently on previous measurements the issue of Xi flow in heavy-ion collisions.
We present pion-Xi correlation analysis in Au-Au collisions at sqrt(s_NN)= 200 GeV and sqrt(s_NN) = 62.4 GeV, performed using the STAR detector at RHIC. A Xi*(1530) resonance signal is observed for the first time in Au-Au collisions. Experimental data are compared with theoretical predictions. The strength of the Xi* peak is reproduced in the correlation function assuming that pions and Xis emerge from a system in collective expansion.