Spectator fragments resulting from relativistic heavy ion collisions, consisting of single protons and neutrons along with groups of stable nuclear fragments up to nitrogen (Z = 7), are measured in ...PHOBOS. These fragments are observed in Au+Au (root s(NN) = 19.6 GeV) and Cu+Cu (22.4 GeV) collisions at high pseudorapidity (eta). The dominant multiply-charged fragment is the tightly bound helium (alpha), with lithium, beryllium, and boron all clearly seen as a function of collision centrality and pseudorapidity. We observe that in Cu+Cu collisions, it becomes much more favorable for the alpha fragments to be released than lithium. The yields of fragments approximately scale with the number of spectator nucleons, independent of the colliding ion. The shapes of the pseudorapidity distributions of fragments indicate that the average deflection of the fragments away from the beam direction increases for more central collisions. A detailed comparison of the shapes for alpha and lithium fragments indicates that the centrality dependence of the deflections favors a scaling with the number of participants in the collision.
We report on measurements of directed flow as a function of pseudorapidity in Au + Au collisions at energies of square root of SNN = 19.6, 62.4, 130 and 200 GeV as measured by the PHOBOS detector at ...the BNL Relativistic Heavy Ion Collider. These results are particularly valuable because of the extensive, continuous pseudorapidity coverage of the PHOBOS detector. There is no significant indication of structure near midrapidity and the data surprisingly exhibit extended longitudinal scaling similar to that seen for elliptic flow and charged particle pseudorapidity density.
We present some of the latest results from the E895 experiment conducted at the BNL AGS accelerator. Au+Au collisions were recorded by the EOS Time Projection Chamber (TPC) at beam energies of 2, 4, ...6, and 8 A GeV. The TPC detector permitted the reconstruction of individual collision events with almost 4π acceptance and good particle identification. This capability allowed E895 to study global observables and two particle correlations with respect to symmetries of the event. Flow excitation functions are examined and discussed in the context of the Nuclear Equation of State.
The ring imaging Cherenkov detector for the BRAHMS experiment at RHIC Debbe, R.; Gushue, S.; Moskowitz, B. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/1996, Letnik:
371, Številka:
1
Journal Article
Recenzirano
Odprti dostop
A ring imaging Cherenkov counter, to be read out by four 100-channel PMTs, is a key element of the BRAHMS experiment. We report here the most recent results obtained with a prototype tested at the ...BNL AGS using several radiator gases, including the heavy fluorocarbon C
4F
10. Ring radii were measured for different particles (
π
−,
μ
−, e
−) for momenta ranging from 2 to 12 GeV/
c employing pure C
4F
10 as radiator.
PDF
