Mid-rapidity anti-proton to proton ratio from Au + Au collisions at s(N N)**(1/2) = 130-GeV.

The STAR collaboration Adler, C. ; Ahammed, Z. ; Allgower, C. ; et al.
Phys.Rev.Lett. 86 (2001) 4778, 2001.
Inspire Record 555818 DOI 10.17182/hepdata.98921

We report results on the ratio of mid-rapidity anti-proton to proton yields in Au+Au collisions at $\rts = 130$ GeV per nucleon pair as measured by the STAR experiment at RHIC. Within the rapidity and transverse momentum range of $|y|<0.5$ and 0.4 $<p_t<$ 1.0 GeV/$c$, the ratio is essentially independent of either transverse momentum or rapidity, with an average of $0.65\pm 0.01_{\rm (stat.)} \pm 0.07_{\rm (syst.)}$ for minimum bias collisions. Within errors, no strong centrality dependence is observed. The results indicate that at this RHIC energy, although the $p$-$\pb$ pair production becomes important at mid-rapidity, a significant excess of baryons over anti-baryons is still present.

4 data tables

pbar over p ratio vs. pt

pbar over p ratio vs. rapidity (y)

pbar over p ratio vs. centrality $(n_{ch}/n_{max})$

More…

Elliptic flow in Au + Au collisions at s(N N)**(1/2) = 130-GeV.

The STAR collaboration Ackermann, K.H. ; Adams, N. ; Adler, C. ; et al.
Phys.Rev.Lett. 86 (2001) 402-407, 2001.
Inspire Record 533414 DOI 10.17182/hepdata.93232

Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at sqrt(s_NN)=130 GeV using the STAR TPC at RHIC. The elliptic flow signal, v_2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.

2 data tables

Elliptic flow as a function of centrality defined as nch/nmax. Also given is epsilon, the initial space eccentricity of the overlap region, as well as the cumulative fraction of events starting with the most central. From the results of the study of non-flow contributions by different subevent selections and the maximum magnitudes of the first and higher-order harmonics, we estimate a systematic error for v2 of about 0.007, with somewhat smaller uncertainty for the mid-centralities where the resolution of the event plane is high.

Elliptic flow as a function of transverse momen-tum for minimum bias events