Pion Interferometry in AuAu Collisions at sqrt{s_{NN}}=200 GeV

Correlations between non-identical particles at small relative velocity probe asymmetries in the average space-time emission points at freeze-out. The origin of such asymmetries may be from long-lived resonances, bulk collective effects, or differences in the freeze-out scenario for the different particle species. STAR has extracted pion-proton correlation functions from a dataset of Au+Au collisions at $\sqrt{s_{NN}}=200$ $GeV$. We present correlation functions in the spheri...

Results are presented on $\pi^\pm$, $K^\pm$, and $\bar{p}$ transverse mass spectra and particle multiplicity ratios at mid-rapidity in Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$=130 and 200 GeV and in p+p collisions at $\sqrt{s}$=200 GeV. Comparisons are made to results from lower energies. The bulk properties of the collision inferred from these results are discussed.

We present data on long-range multiplicity correlations in ultra-relativistic heavy ion collisions at the top RHIC energy ($\sqrt{s_{NN}}$ = 200 GeV) from the STAR experiment. The data shows a long-range multiplicity correlation extending across a gap of 1.6 units in pseudorapidity. The data is over predicted by a multiparticle production model with hadronization of independent strings, or fusion of two color strings. This can be interpreted in terms of additional dynamical r...

One of the primary aims of heavy-ion collisions is to map the QCD phase diagram and search for different phases and phase boundaries. RHIC Energy Scan Program was launched to address this goal by studying heavy-ion collisions at different center of mass energies. The first test run with Au+Au collisions at $\sqrt{s_{NN}}$ = 9.2 GeV took place in early 2008. The large acceptance STAR detector has collected few thousands minimum bias collisions at this beam energy. We present t...

Neutral pions with p_T = 1 - 8 GeV/c have been measured for 9 different centrality classes in Au+Au collisions at sqrt(s_NN) = 200 GeV by the PHENIX experiment at RHIC. The pi^0 multiplicity in central reactions is significantly below the binary collision scaled yields from both peripheral Au+Au and pp reactions. The observed suppression sets in for the 50-70% centrality class and increases with p_T and centrality. For the most central bin, the deficit amounts to a factor ~2....

Three-dimensional source images for mid-rapidity, low transverse momentum kaon and pion pairs have been extracted from central Au+Au collisions data at \sqrt{s_{NN}} = 200 GeV by the STAR experiment at RHIC. The pion source function displays significant non-Gaussian features implying a finite pion emission duration. On the other hand, the kaon source function is essentially Gaussian, consistent with instantaneous emission from the fireball.

Neutral pions ($\pi^0$) in $\sqrt{s_\mathrm{NN}}$ = 200 GeV and 62.4 GeV Au+Au collisions were measured at RHIC-PHENIX Year-4 Run. In $\sqrt{s_\mathrm{NN}}$ = 200 GeV, $\pi^0$ specta are measured up to p$_\mathrm{T}$ = 20 GeV/$c$. %PHENIX extended the p$_\mathrm{T}$ region of A strong suppression by a factor of $\sim$ 5 is observed and stays almost constant up to 20 GeV/$c$.

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 transver...

We investigate the two-pion interferometry in ultrarelativistic heavy ion collisions in the granular source model of quark-gluon plasma droplets. The pion transverse momentum spectra and HBT radii of the granular sources agree well with the experimental data of the most central Au-Au collisions at $\sqrt{s_{NN}}=200$ GeV at RHIC and Pb-Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV at LHC. In the granular source model the larger initial system breakup time for the LHC collisions a...

We present high transverse momentum, $p_{T}$, pion ($\pi$), proton ($p$), kaon ($K$), and rho ($\rho$) spectra measured with the STAR experiment from p+p and Au+Au collisions with \sNN{200}. We find the $K/\pi$ ratio to be enhanced in Au+Au \sNN{200} collisions relative to p+p \sNN{200} collisions at $p_{T} > 5$ GeV/c. The enhancement persists until $p_{T} \sim 12$ GeV/c for central Au+Au 200 GeV collisions. We also show the nuclear modification factor, $R_{AA}$, measured at ...