共查询到20条相似文献,搜索用时 0 毫秒
1.
Bin Zhang 《Physics letters. [Part B]》2004,580(3-4):144-148
The transverse profile dependence of elliptic flow is studied in a parton cascade model. We compare results from the binary scaling profile to results from the wounded nucleon scaling profile. The impact parameter dependence of elliptic flow is shown to depend sensitively on the transverse profile of initial particles, however, if elliptic flow is plotted as a function of the relative multiplicity, the nuclear profile dependence disappears. The insensitivity was found previously in a hydrodynamical calculation. Our calculations indicate that the insensitivity is also valid with additional viscous corrections. In addition, the minimum bias differential elliptic flow is demonstrated to be insensitive to the nuclear profile of the system. 相似文献
2.
In this contribution I present a review on the actual status of dilepton measurements at SPS and RHIC energies and the current theoretical interpretations. Model independent results will be pointed out for both energies. Due to partially conflicting theoretical concepts I will highlight the open questions that may be solved by extended theoretical as well as experimental studies. 相似文献
3.
We calculate the baryon flow Px/A(y) in the energy range from 0.25 to 4.0A GeV in a relativistic transport model for Ni + Ni and Au + Au collisions employing various models for the baryon self-energies. We find that to describe the flow data of the FOPI Collaboration above 1A GeV the strength of the vector potential has to be reduced at high relative momentum or at high density. The latter phenomenon leads to a softening of the nuclear equation of state at high density. 相似文献
4.
A. Kozlov 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):836-841
The production of the low-mass dielectrons is considered to be a powerful tool to study the properties of the hot and dense
matter created in the ultra-relativistic heavy-ion collisions. We present the preliminary results on the first measurements
of the low-mass dielectron continuum in Au + Au collisions and the φ-meson production measured in Au + Au and d + Au collisions at
= 200GeV performed by the PHENIX experiment. 相似文献
5.
R. Andrade F. Grassi Y. Hama T. Kodama O. Socolowski jr. B. Tavares 《The European Physical Journal A - Hadrons and Nuclei》2006,29(1):23-26
Elliptic flow at RHIC is computed event by event with NeXSPheRIO. Reasonable agreement with experimental results on v
2(η) is obtained. Various effects are studied as well: reconstruction of impact parameter direction, freeze-out temperature,
equation of state (with or without crossover), emission mechanism. 相似文献
6.
J. T. Mitchell 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):851-853
The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has made measurements of event-by-event fluctuations in
the charged-particle multiplicity as a function of collision energy, centrality, collision species, and transverse momentum
in several heavy-ion collision systems. It is observed that the fluctuations in terms of σ
2/μ
2 exhibit a universal power law scaling as a function of Nparticipants that is independent of the transverse momentum range of the measurement. 相似文献
7.
8.
Bedangadas Mohanty 《Pramana》2006,67(5):927-935
We present some of the important experimental results from nucleus-nucleus collision studies carried out by the STAR experiment
at Relativistic Heavy Ion Collider (RHIC). The results suggests that central Au+Au collisions at RHIC has produced a dense
and rapidly thermalizing matter with initial energy densities above the critical values predicted by lattice QCD for establishment
of a quark-gluon plasma (QGP). 相似文献
9.
M. Csanád T. Csörgő A. Ster B. Lörstad N. N. Ajitanand J. M. Alexander P. Chung W. G. Holzmann M. Issah R. A. Lacey 《The European Physical Journal A - Hadrons and Nuclei》2008,38(3):363-368
Recent PHOBOS measurements of the excitation function for the pseudo-rapidity dependence of the elliptic flow in Au + Au collisions
at RHIC have posed a significant theoretical challenge. Here we show that these differential measurements, as well as the
RHIC measurements on transverse momentum satisfy a universal scaling relation predicted by the Buda-Lund model, based on exact
solutions of perfect fluid hydrodynamics. We also show that the recently found transverse kinetic energy scaling of the elliptic
flow is a special case of this universal scaling. 相似文献
10.
We calculate the one-particle hadronic spectra and correlation functions of pions based on a hydrodynamical model. Parameters
in the model are so chosen that the one-particle spectra reproduce experimental results of √s= 130 AGeV Au + Au collisions at RHIC. Based on the numerical solution, we discuss the space-time evolution of the fluid. Two-pion
correlation functions are also discussed. Our numerical solution suggests the formation of the quark-gluon plasma with large
volume and low net baryon density. 相似文献
11.
Bedangadas Mohanty 《Pramana》2003,60(4):613-625
Results from the photon multiplicity measurements using a fine granularity pre-shower photon multiplicity detector (PMD) at
CERN SPS are discussed. These include study of pseudorapidity distributions of photons, scaling of photon multiplicity with
number of participating nucléons, centrality dependence of 〈p
T〉 of photons, event-by-event fluctuations in photon multiplicity and localised charged-neutral fluctuations. Basic features
of the PMD to be used in STAR experiment at RHIC and in ALICE experiment at LHC are also discussed. 相似文献
12.
STAR’s measurement of directed flow for pions,kaons(K 0 S ),protons and anti-protons,for Au+Au collisions at 200 GeV obtained in Run7 are presented,as well as elliptic flow for identified particles measured in Au+Au(Run7) and Cu+Cu(Run5) collisions.It is found that the slope of proton v 1 (y) at midrapidity is extremely small.Elliptic flow results are compared to Hydro calculation and the discrepancy is discussed. 相似文献
13.
STAR’s measurement of directed flow for pions,kaons(K 0 S ),protons and anti-protons,for Au+Au collisions at 200 GeV obtained in Run7 are presented,as well as elliptic flow for identified particles measured in Au+Au(Run7) and Cu+Cu(Run5) collisions.It is found that the slope of proton v 1 (y) at midrapidity is extremely small.Elliptic flow results are compared to Hydro calculation and the discrepancy is discussed. 相似文献
14.
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16.
Abhay Deshpande 《Pramana》2003,61(5):859-864
In 2001–2002 the relativistic heavy-ion collider (RHIC) at the Brookhaven National Laboratory (BNL) was first commissioned
for polarized proton collisions. Polarized protons were injected into the RHIC, accelerated to 100 GeV, stored and the two
beams were made to collide in four interaction regions. I will review the progress made by the RHIC spin program, followed
by the physics goals for the next few years. After that I will present a brief overview of a proposal to build a high intensity
polarized electron/positron beam facility at BNL which would enable deep inelastic scattering (DIS) experiments to be pursued
at BNL by its collisions with the RHIC hadron beams. 相似文献
17.
T. Hirano 《The European Physical Journal A - Hadrons and Nuclei》2006,29(1):19-22
We can establish a new picture, the perfect fluid sQGP core and the dissipative hadronic corona, of the space-time evolution
of produced matter in relativistic heavy-ion collisions at RHIC. It is also shown that the picture works well also in the
forward rapidity region through an analysis based on a new class of the hydro-kinetic model and that this is a manifestation
of the rapid increase of the entropy density in the vicinity of QCD critical temperature, namely, deconfinement. 相似文献
18.
19.
M. J. Leitch 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):868-874
At the Relativistic Heavy-Ion Collider (RHIC) collisions of heavy ions at nucleon-nucleon energies of 200GeV appear to have
created a new form of matter thought to be a deconfined state of the partons that ordinarily are bound in nucleons. We discuss
the evidence that a thermalized partonic medium, usually called a Quark Gluon Plasma (QGP), has been produced. Then, we discuss
the effect of this high-density medium on the production of jets and their pair correlations. Next, we look at direct photons
as a clean electro-magnetic probe to constrain the initial hard scatterings. Finally, we review the developing picture for
the effect of this medium on the production of open heavy quarks and on the screening by the QGP of heavy-quark bound states. 相似文献
20.
《Pramana》2003,60(5):921-931
The PHOBOS detector has been used to study Au + Au collisions at√sNN = 56,130, and 200 GeV Several global observables have been measured and the results are compared with theoretical models.
These observables include the charged-particle multiplicity measured as a function of beam energy, pseudo-rapidity, and centrality
of the collision. A unique feature of the PHOBOS detector is its almost complete angular coverage such that these quantities
can be studied over a pseudo-rapidity interval of |η|≤5.4. This allows for an almost complete integration of the total charged
particle yield, which is found to be about N
ch
tot
= 4200 ±470 at √sNN = 130 GeV and N
ch
tot
= 5300 ±530 at √sNN = 200 GeV.
The ratio of anti-particles to particles emitted in the mid-rapidity region has also been measured using the PHOBOS magnetic
spectrometer. Of particular interest is the ratio of anti-protons to protons in the mid-rapidity region, which was found to
be (i.e.921-1) at √sNN = 130 GeV. This high value suggests that an almost baryon-free region has been produced in the collisions. 相似文献