105 research outputs found
Event anisotropy of identified , photon and electron compared to charged , , and deuteron in = 200 GeV Au+Au at PHENIX
We report the recent results of event anisotropy analysis focused on in
= 200 GeV Au+Au collisions at PHENIX.Comment: 4 pages, 3 figures, contribution to the proceedings of the 17th
International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions
(Quark Matter, Oakland, January 11-17, 2004). To appear in the proceedings
(Journal of Physics G
Jet Fragmentation in Vacuum and Medium with gamma-hadron Correlations in PHENIX
Jet fragmentation in p+p and Au+Au collisions is studied via back-to-back
correlations of direct photons and charged hadrons. The direct photon
correlations are obtained by statical subtraction of the background from decay
photons. Results on the nuclear modification to the associated charged hadron
yields are reviewed. Further studies of jet fragmentation in p+p using isolated
direct photons are also presented. A kT-smeared LO pQCD calculation is used to
interpret the data. The sensitivity of the data to the underlying fragmentation
function is tested and the results are found to be compatible with expectations
of a sample dominated by quark jet fragmentation.Comment: Talk presented at Hot Quarks 2010, June 21-26, La Londe Les Maures,
France. To be published in Journal of Physics: Conference Series (JPCS
Strangeness and heavy flavor at RHIC: Recent results from PHENIX
We report recent results of strangeness and heavy flavor measurements from
PHENIX.
The topics are: Elliptic flow of strangeness and heavy flavor electron
production comparing to the other hadrons, meson production, and an
exotic particle search.Comment: 8 pages, 6 figures, 1 table. Submitted to J. Phys. G (Proceedings of
the 8th International Conference on Strangeness in Quark Matter, Cape Town,
South Africa, September 15-20, 2004
Hadron Production at Intermediate at RHIC
Large proton and antiproton enhancement with respect to pions has been
observed at intermediate transverse momentum 2-5 GeV/ in Au+Au
collisions at RHIC. To investigate the possible source of this anomaly, the
production of mesons and two particle angular correlations triggered by
mid- baryons or mesons are studied. We also present the first measurement
of proton and antiproton production at GeV in Au+Au
collisions, which aims to study the energy dependence of the observed baryon
enhancement.Comment: 7 pages, 5 figures, proceedings of Hot Quarks 2004 workshop, Taos
Valley, New Mexico, 18-24 Jul 2004,, to be published in J. Phys.
Excitation functions of baryon anomaly and freeze-out properties at RHIC-PHENIX
The intermediate region (2 - 5 GeV/) in central Au+Au collisions at
RHIC has a rich physics content. The (anti)proton to pion ratio at the
intermediate gives us a powerful tool to investigate the bulk properties
of the hot and dense matter created at RHIC and their hadronization processes.
We present the preliminary results of identified charged hadron spectra at the
lower beam energies at RHIC. The excitation function of (anti)proton to pion
ratios from SPS to RHIC are shown. We also discuss the onset of the baryon
enhancement at the high energy heavy ion collisions.Comment: 4 pages, 3 figures, Quark Matter 2006 conference proceeding
PHENIX Measurement of High- Hadron-hadron and Photon-hadron Azimuthal Correlations
High- hadron-hadron correlations have been measured with the PHENIX
experiment in \Cu and \pp collisions at GeV. A
comparison of the jet widths and yields between the two colliding systems
allows us to study the medium effect on jets. We also present a first
measurement of direct photon-hadron correlations in \Au and \pp collisions.
We find that the near-side yields are consistent with zero in both systems. By
comparing the jet yields on the away side, we observe a suggestion of the
expected suppression of hadrons associated with photons in \Au collisions.Comment: 5 pages, proceeding for parallel talk on Quark Matter 200
Anti-nuclei and nuclei production in Pb+Pb collisions at CERN SPS energies
We present new results on production of 3He and t obtained by the NA49
experiment in 20A, 30A, 40A and 80A GeV central Pb+Pb collisions at the CERN
SPS. Transverse mass spectra and rapidity distributions for clusters measured
over a large phase space domain are discussed. We observe a weak dependence of
the mid-rapidity t/3He ratio on collision energy at SPS. The energy dependence
of the total yield for 3He is remarkably reproduced by a statistical hadron gas
model. A gradual decrease of the coalescence parameter B3 for 3He with is observed.In addition, a measurement of the yield of anti-deuterons
in Pb+Pb reactions at SPS's top energy of = 17.2 GeV is
presented.Comment: 4 pages, 8 figures. Talk at HEP07, Manchester, July 19-25, 2007;
submitted to Journal of Physics: Conference Serie
Traces of Thermalization at RHIC
I argue that measurements of Au+Au collisions at 20, 130 and 200 GeV of the
centrality dependence of the mean p_t together with p_t and net-charge
fluctuations reflect the approach to local thermal equilibrium.Comment: 4 pages, 4 eps figures, for proc. Quark Matter 2004, to be published
in J. Phys.
Diagnosing Energy Loss: PHENIX Results on High-pT Hadron Spectra
Measurements of inclusive spectra of hadrons at large transverse momentum
over a broad range of energy in different collision systems have been performed
with the PHENIX experiment at RHIC. The data allow to study the energy and
system size dependence of the suppression observed in RAA of high-pT hadrons at
sqrt(s_NN)= 200 GeV. Due to the large energy range from sqrt(s_NN)= 22 GeV to
200 GeV, the results can be compared to results from CERN SPS at a similar
energy. The large Au+Au dataset from the 2004 run of RHIC also allows to
constrain theoretical models that describe the hot and dense matter produced in
such collisions. Investigation of particle ratios such as eta/pi0 helps
understanding the mechanisms of energy loss.Comment: 4 pages, 6 figures. To appear in the proceedings of the 19th
International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions
(Quark Matter 2006), Shanghai, China, November 14-20, 200
Baryonic Effect on chi_cJ Suppression in Au+Au Collisions at RHIC Energies
We predict that initially produced chi_cJ mesons at low transverse momentum
in the central rapidity region are almost dissociated by nucleons and
antinucleons in hadronic matter produced in central Au+Au collisions at RHIC
energies sqrt {s_{NN}}= 130 and 200 GeV. In calculations the nucleon and
antinucleon distributions in hadronic matter are results of evolution from
their freeze-out distributions which well fit the experimental p_T spectra of
proton and antiproton. Any measured chi_cJ mesons at low p_T are generated from
deconfined matter and give an explicit proof of regeneration mechanism
(recombination mechanism).Comment: 10 pages, 3 figures, Latex, a discussion added to the referenc
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