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1.
The structure of hadron–hadron correlations is investigated in proton–proton (pp) collisions. We focus on the transmission of the initial transverse momenta of partons (“intrinsic kT”) to the hadron–hadron correlations. Values of the intrinsic transverse-momentum obtained from experimental correlations are compared to the results of a model with partially randomized parton transverse momenta at ISR and RHIC energies. Procedures for extracting the correlations from data are discussed. 相似文献
2.
K. Ozawa 《The European Physical Journal C - Particles and Fields》2005,43(1-4):421-426
Recent results on low mass dilepton measurements from the PHENIX experiment are reported. Invariant mass spectra of
are measured for the first time in Au-Au collisions at
GeV in Run2. In d-Au collisions, the yields and MT slopes of both
and
are measured. Both results are consistent with each other within errors. In the future, a Hadron Blind Detector will be installed
in PHENIX which will enhance our capabilities of rejecting external photon conversions and Dalitz pairs, that will result
in a significant reduction of the large combinatorial background.
* Deceased
Spokesperson 相似文献
3.
R. Lietava J. Pisút N. Pisútová B. Tomásik 《The European Physical Journal C - Particles and Fields》2003,28(1):119-122
We propose a simple Glauber-type mechanism for the suppression of jet production up to transverse momenta of about 10 at RHIC. For processes in this kinematic region, the formation time is smaller than the interval between two successive hard
partonic collisions and the subsequent collision influences the jet production. The number of jets then roughly scales with
the number of participants. Proportionality to the number of binary collisions is reco
vered for very high transverse momenta. The model predicts suppression of jet production in collisions at RHIC.
Received: 20 January 2003 / Published online: 7 March 2003 相似文献
4.
The energy and centrality dependence of the charged multiplicity per participant nucleon is shown to be able to differentiate between final state saturation and fixed scale perturbative QCD models of initial entropy production in high-energy heavy-ion collisions. The energy dependence is shown to test the nuclear enhancement of the minijet component of the initial conditions, while the centrality dependence provides a key test of whether gluon saturation is reached at RHIC energies. The HIJING model predicts that the rapidity density per participant increases with centrality, while the saturation model prediction is essentially independent of centrality. 相似文献
5.
6.
The implications of parton rearrangement processes on the dynamics of ultra-relativistic heavyion collisions have been investigated.
A microscopic transport approach, namely the quark gluon string model (QGSM) which has been extended for a locally density-dependent
partonic rearrangement and fusion procedure served as the tool for this investigations. The model emulates effectively the
dynamics of a strongly coupled quark plasma and final hadronic interactions. Main QGSM results on anisotropic flow components
v
1 and v
2 at top RHIC energy are compiled. Predictions for the pseudorapidity dependence of directed and elliptic flow in Pb+Pb collisions
under LHC conditions are presented. 相似文献
7.
We investigate the non-statistical multiplicity fluctuations (intermittency) of hadrons produced in high-energy collisions. Within the framework of the two-mechanism model, we determine the limits of the intermittent regions. We observe that these regions decrease in extent with increasing total energy $\sqrt s$ . In addition, we determine the value of the exponent from the universal scaling law (discovered recently by R. Hwa et al.). The value of this exponent is close to corresponding experimental data. 相似文献
8.
S. S. Padula D. M. Dudek O. SocolowskiJr. 《Physics of Particles and Nuclei Letters》2011,8(9):951-954
In high energy heavy ion collisions a hot and dense medium is formed, where the hadronic masses may be shifted from their
asymptotic values. If this mass modification occurs, squeezed back-to-back correlations (BBC) of particle-antiparticle pairs
are predicted to appear, both in the femionic (fBBC) and in the bosonic (bBBC) sectors. Although they have unlimited intensity
even for finite-size expanding systems, these hadronic squeezed correlations are very sensitive to their time emission distribution.
Here we discuss results in case this time emission is parameterized by a Lévy-type distribution, showing that it reduces the
signal even more dramatically than a Lorentzian distribution, which already reduces the intensity of the effect by orders
of magnitude, as compared to the sudden emission. However, we show that the signal could still survive if the duration of
the process is short, and if the effect is searched for lighter mesons, such as kaons. We compare some of our results to recent
PHENIX preliminary data on squeezed correlations of K
+
K
− pairs. 相似文献
9.
Iwona M. Sakrejda 《Acta Physica Hungarica A》1996,4(1-4):117-121
In search for the Quark Gluon Plasma, which is one of the most exciting tasks of the Nuclear Physics these days, experimentalists reach for higher and higher energies in hope to establish most favourable conditions for its creation. A new generation of experiments for the RHIC accelerator is under construction and will be ready to take data in 1999. The focus for the STAR detector, located in the Wide Angle Hall of the RHIC accelerator, are hadronic observables. This paper will present STAR capabilities in the area of strangeness measurements and its ability to correlate them with other event characteristics. 相似文献
10.
We modified the gluon saturation model by rescaling the momentum fraction according to saturation momentum and introduced Cooper-Frye hydrodynamic evolution to systematically study the pseudo-rapidity distributions of final charged hadrons at different energies and different centralities for Au-Au collisions in relativistic heavy-ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC). The features of both gluon saturation and hydrodynamic evolution at different energies and different centralities for Au-Au collisions are investigated in this paper. 相似文献
11.
Huichao Song 《Central European Journal of Physics》2012,10(6):1242-1244
In this proceeding, we briefly describe the viscous hydrodynamics + hadron cascade hybrid model VISHNU for relativistic heavy ion collisions and report the current status on extracting the QGP viscosity from elliptic flow data. 相似文献
12.
The urgency of predictions in the large-t region at LHC stimulated us to present a unified model of small- and high-t scattering
at high energies. Our model is based on safe theoretical ground: analyticity, unitarity, Regge behavior, gluon exchange and
saturation of bounds established in axiomatic quantum field theory. We make precise predictions for the behavior of the differential
cross sections at high t, the evolution of the dip–shoulder structure localized in the region 0.5 ≲ |t| ≲ 0.8 GeV2 and the radical violation of the exponential behavior of the first diffraction cone at small t.
PACS 12.40.Nn; 13.75.Cs; 13.85.Dz; 13.85.Lg 相似文献
13.
PACIAE, a parton and hadron cascade model, is utilized to systematically investigate strange particle production and strangeness enhancement in Au+Au collisions and in Pb+Pb collisions with the √SNN = 200 GeV at the RHIC and 2.76 TeV at the LHC, respectively. The experimental results at different centralities, using data from the STAR collaboration and the ALICE collaboration, are well described by the PACIAE model. This may represent the importance of the parton and hadron rescatterings, as well as the reduction mechanism for strange quark suppression, that are implemented in the PACIAE model. 相似文献
14.
PACIAE, a parton and hadron cascade model, is utilized to systematically investigate strange particle production and strangeness enhancement in Au+Au collisions and in Pb+Pb collisions with the √sNN=200 GeV at the RHIC and 2.76 TeV at the LHC, respectively. The experimental results at different centralities, using data from the STAR collaboration and the ALICE collaboration, are well described by the PACIAE model. This may represent the importance of the parton and hadron rescatterings, as well as the reduction mechanism for strange quark suppression, that are implemented in the PACIAE model. 相似文献
15.
16.
《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
17.
Considering the magnetic field response of the QGP medium,we perform a systematical study of the chiral magnetic effect(CME),and make a comparison with the experimental results for the background-subtracted correlator H at the energies of the RHIC Beam Energy Scan(BES)and the LHC energy.The CME signals from our computations show a centrality trend and beam energy dependence that are qualitatively consistent with the experimental measurements of the charge dependent correlations.The time evolution of the chiral electromagnetic current at the RHIC and LHC energies is systematically studied.The dependence of the time-integrated current signal on the beam energy√s with different centralities is investigated.Our phenomenological analysis shows that the time-integrated electromagnetic current is maximal near the collision energy√s≈39 GeV.The qualitative trend of the induced electromagnetic current is in agreement with the CME experimental results at the RHIC and LHC energies. 相似文献
18.
K. Reygers 《The European Physical Journal C - Particles and Fields》2005,43(1-4):393-398
Direct photons are an important tool for the detection of the quark-gluon plasma in ultra-relativistic nucleus-nucleus collisions. Direct-photon measurements were made in Pb + Pb collisions at
GeV and in Au + Au collisions at
GeV. These results are reviewed and compared with model calculations.Arrival of the final proofs: 9 May 2005PACS:
25.75.DwThis revised version was published online in July 2005 with a correction to the article category and incorporation of the revised date. 相似文献
19.
20.
G.H. Arakelyan C. Merino C. Pajares Y.M. Shabelski 《The European Physical Journal C - Particles and Fields》2008,54(4):577-581
We consider the phenomenological implications of the assumption that baryons are systems of three quarks connected through
a gluon string junction. The transfer of baryon number in rapidity space due to the string junction propagation is considered
in detail. At high energies this process leads to a significant effect on the net baryon production in hN collisions at midrapidities.
The numerical results for midrapidity inclusive densities of different secondaries in the framework of the quark–gluon string
model are in reasonable agreement with the experimental data. One universal value, λ≃0.25, for the strangeness suppression
parameter correctly describes the yield ratios of Λ/p, Ξ/Λ, and Ω/Ξ. The predictions for pp collisions at LHC energies are
also presented.
PACS 25.75.Dw 相似文献