M. Heinz

Strange particle production in p + p collisions at

We present strange particle spectra and yields measured at mid-rapidity in sqrt text s=200 GeV proton-proton (p+p) collisions at RHIC. We find that the previously observed universal transverse mass (mathrm mT \equiv\sqrt mathrm p_T 2+\mathrm m2) scaling of hadron production in p+p collisions seems to break down at higher \mt and that there is a difference in the shape of the \mt spectrum between baryons and mesons. We observe mid-rapidity anti-baryon to baryon ratios near unity for Lambda and Xi baryons and no dependence of the ratio on transverse momentum, indicating that our data do not yet reach the quark-jet dominated region. We show the dependence of the mean transverse momentum (\mpt) on measured charged particle multiplicity and on particle mass and infer that these trends are consistent with gluon-jet dominated particle production. The data are compared to previous measurements from CERN-SPS, ISR and FNAL experiments and to Leading Order (LO) and Next to Leading order (NLO) string fragmentation model predictions. We infer from these comparisons that the spectral shapes and particle yields from

How well does NLO pQCD describe strangeness production in p + p collisions at GeV in STAR?

p+p

Systematic study of the jet fragmentation function for inclusive jet-production in p+p collisions at \(\sqrt{s}=200\) GeV in STAR

collisions at RHIC energies have large contributions from gluon jets rather than quark jets.

Identified Baryon and Meson Distributions at Large Transverse Momenta from Au+Au Collisions at {radical}(s{sub NN})=200 GeV

We present measurements of the transverse momentum spectra for K 0 S , A, E and their antiparticles in p + p collisions at √s = 200 GeV. The extracted mid-rapidity yields and (p T ) are in agreement with previous p + p experiments while they have smaller statistical errors. We compare the measured spectra for K 0 S and A to the latest available calculations from NLO pQCD and see good agreement for the K 0 S above 1.5 GeV/c.

Strange particle production in p + p collisions at \sqrt{{s}}= 200 \ {\rm GeV}

AbstractJet fragmentation functions measured in e+e− and

Azimuthal anisotropy in Au+Au collisions at √ sNN = 200 GeV

p+\bar{p}

How important are next-to-leading order models in predicting strange particle spectra in p+p collisions at STAR?

experiments are well-described on an inclusive hadron level by QCD-based calculations. Fragmentation is expected to be modified by the presence of a strongly interacting medium, but full theoretical description of this modification must still be developed. It has recently been suggested that particle-identified fragmentation functions may provide additional insight into the processes underlying jet quenching. To assess the applicability of QCD-based fragmentation calculations to RHIC data, and to provide a baseline with which to compare fragmentation function measurements in heavy ion collisions, we present the first measurements of charged hadron and particle-identified fragmentation functions of jets reconstructed via a midpoint-cone algorithm from p+p collisions at 200 GeV in STAR. We study the dependence on jet cone-size and jet-energy, and compare the results to PYTHIA simulations based on the Modified Leading Log Approximation (MLLA).

Measurements ofmeson production in relativistic heavy-ion collisions at RHIC

Transverse momentum spectra of pi+/-, p, and p up to 12 GeV/c at midrapidity in centrality selected Au + Au collisions at square root sNN=200 GeV are presented. In central Au + Au collisions, both pi +/- and p(p) show significant suppression with respect to binary scaling at pT approximately >4 GeV/c. Protons and antiprotons are less suppressed than pi+/-, in the range 1.5 approximately < pT approximately < 6 GeV/c. The pi-/pi+ and p/p ratios show at most a weak pT dependence and no significant centrality dependence. The p/pi ratios in central Au + Au collisions approach the values in p + p and d + Au collisions at pT approximately >5 GeV/c. The results at high pT indicate that the partonic sources of pi+/-, p, and p have similar energy loss when traversing the nuclear medium.

Pion interferometry in Au+Au collisions at v sNN = 200 GeV

We present strange particle spectra and yields measured at mid-rapidity in sqrt text s=200 GeV proton-proton (p+p) collisions at RHIC. We find that the previously observed universal transverse mass (mathrm mT \equiv\sqrt mathrm p_T 2+\mathrm m2) scaling of hadron production in p+p collisions seems to break down at higher \mt and that there is a difference in the shape of the \mt spectrum between baryons and mesons. We observe mid-rapidity anti-baryon to baryon ratios near unity for Lambda and Xi baryons and no dependence of the ratio on transverse momentum, indicating that our data do not yet reach the quark-jet dominated region. We show the dependence of the mean transverse momentum (\mpt) on measured charged particle multiplicity and on particle mass and infer that these trends are consistent with gluon-jet dominated particle production. The data are compared to previous measurements from CERN-SPS, ISR and FNAL experiments and to Leading Order (LO) and Next to Leading order (NLO) string fragmentation model predictions. We infer from these comparisons that the spectral shapes and particle yields from

Growth of Long Range Forward-Backward Multiplicity Correlations with Centrality in Au þ Au Collisions at ffiffiffiffiffiffiffiffiffi

p+p