Does the charm flow at RHIC? Batsouli, S.; Kelly, S.; Gyulassy, M. ...
Physics letters. B,
03/2003, Volume:
557, Issue:
1-2
Journal Article
Peer reviewed
Open access
Recent PHENIX Au+Au→e−+X data Phys. Rev. Lett. 88 (2002) 192303 from open charm decay are shown to be consistent with two extreme opposite dynamical scenarios of ultra-relativistic nuclear reactions. ...Perturbative QCD without final state interactions was previously shown to be consistent with the data. However, we show that the data are also consistent with zero mean free path hydrodynamics characterized by a common transverse flow velocity field. The surprising coincidence of both D and B hydrodynamic flow spectra with pQCD up to pT≈3 and 5 GeV, respectively, suggests that heavy quarks may be produced essentially at rest in the rapidly expanding gluon plasma. Possible implications and further tests of collective heavy quark dynamics are discussed.
We present Experiment 864's measurement of invariant antideuteron yields in 11.5A GeV/c Au+Pt collisions. The analysis includes 250x10(6) triggers representing 14x10(9) 10% central interactions ...sampled for events with high mass candidates. We find (1/2pip(t))d(2)N/dydp(t) = 3.5+/-1.5(stat)+0.9-0.5(syst)x10(-8) GeV-2 c(2) for 1.8<y<2.2, < p(t)> = 0.35 GeV/c ( y(c.m.) = 1.6) and 3.7+/-2.7(stat)+1.4-1.5(syst)x10(-8) GeV-2 c(2) for 1.4<y<1.8, < p(t)> = 0.26 GeV/c, and a coalescence parameter B2; of 4.1+/-2. 9(stat)+2.3-2.4(syst)x10(-3) GeV2 c(-3). Implications for coalescence and antimatter annihilation are discussed.
We present a Glauber-based study of J/
Ψ and Drell–Yan yields in nucleus–nucleus collisions. Using this approach, we have investigated the impact of energy loss by the colliding nuclei on observed ...yields and transverse momentum spectra of J/
Ψ and Drell–Yan. These studies permit an assessment of the importance of initial state energy loss in relation to “anomalous” J/
Ψ suppression.
We report on leptonic observables by the PHENIX experiment from data taken during Run II at the Relativistic Heavy Ion Collider (RHIC). We show first results on φ →
K
+
K
−,
e
+
e
−, low and ...intermediate mass dielectron continuum, single electrons from charm, and
J/ψ yields in proton-proton and Au
Au collisions at
S
N
N
=
200
GeV.
Light nuclei can be produced in the central reaction zone via coalescence in relativistic heavy-ion collisions. Experiment 864 at BNL has measured the production of ten light nuclei with nuclear ...number A=1 to A=7 at rapidity y{approx_equal}1.9 and p{sub T}/A{<=}300 MeV/ c . Data were taken with a Au beam of momentum of 11.5A GeV/c on a Pb or Pt target with different experimental settings. The invariant yields show a striking exponential dependence on nuclear number with a penalty factor of about 50 per additional nucleon. Detailed analysis reveals that the production may depend on the spin factor of the nucleus and the nuclear binding energy as well. (c) 1999 The American Physical Society.
The Relativistic Heavy Ion Collider (RHIC) facility at Brookhaven National Laboratory is the first accelerator specifically constructed for the study of very hot and dense nuclear matter. At ...sufficiently high temperature, nuclear matter is expected to undergo a phase transition to a quark-gluon plasma. It is the specific goal of the field to study the nature of this plasma and understand the phase transitions between different states. The RHiC accelerator along with four experiments BRAHMS, PHENIX, PHOBOS, and STAR were commissioned last year with first collisions occurring in June 2000. Presented here are the first results from low luminosity beam in Run I. They are a glimpse of the wealth of physics to be extracted from the RHIC program over the next several years. (Author)
A methodology for developing congestion management–related projects for the Indiana state highway network is described. The methodology is based on a sketch planning analysis technique that can be ...used with limited input data. The software package provides estimates of costs and other effects of potential congestion mitigation projects to undertake in a given year, which can be used by planners and programmers in long-range planning. Project types include road widening, high-occupancy-vehicle facilities, ramp metering, incident management, and arterial traffic signal coordination. The impact is assessed in travel time savings, vehicle operating cost savings, crash cost savings, and emission reductions. An example application of the methodology is given for the 7.81-mi segment of I-65 between Interchanges 116 and 123 in the Indianapolis area.
Deuteron production in S- and Pb-induced collisions at ultrarelativistic energies is studied in a transport model, treating the deuteron production by phase space coalescence. The production rate of ...deuterons as a function of rapidity,
dN
d
dy
, is approximately found to satisfy a simple scaling behavior in terms of the proton and the pion rapidity distributions,
dN
p
dy
and
dN
π
dy
, namely
dN
d
dy ∼
(
dN
p
dy
)
2/(
dN
π
dy
)
. The scaling is a consequence of the near equality of the freeze-out volumes the nucleons and mesons. Violation of the scaling is attributed to differences between these freeze-out volumes.
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