352 research outputs found
- meson Production at RHIC energies using the PHENIX Detector
Light vector mesons are among the most informative probes to understand the
strongly coupled Quark Gluon Plasma created at RHIC. The suppression of light
mesons at high transverse momentum, compared to expectations from scaled
results, reflects the properties of the strongly interacting matter formed. The
-meson is one of the probes whose systematic measurement in ,
and collisions can provide useful information about initial and final
state effects on particle production. The mass, width and branching ratio of
the -meson decay in the di-kaon and di-electron decay channels could be
modified in \au collisions due to the restoration of chiral symmetry in the
QGP. The PHENIX experiment at RHIC has measured -meson production in
various systems ranging form , to collisions via both its
di-electron and di-kaon decay modes. A summary of PHENIX results on invariant
spectra, nuclear modification factor and elliptic flow of the -meson are
presented here
New faunistic data on Dolichopodidae (Diptera) from Turkey
Faunistic data is given for 83 species of Dolichopodidae from Turkey. The following genera are recorded for the first time in Turkey: Achalcus Loew, 1857, Cyrturella Collin, 1952, and Trigonocera Becker, 1902; 21 species are recorded for the first time in Turkey: Achalcus flavicollis (Meigen, 1824), Aphrosylus venator Loew, 1857, Asyndetus separatus (Becker, 1902), Chrysotus larachensis Grichanov, Nourti et Kettani, 2020, Cyrturella albosetosa (Strobl, 1909), Hydrophorus bipunctatus (Lehmann, 1822), Lamprochromus bifasciatus (Macquart, 1827), Lamprochromus kowarzi Negrobov et Tshalaja, 1988, Medetera petrophiloides Parent, 1925, M. signaticornis Loew, 1957, Orthoceratium sabulosum (Becker, 1907), Rhaphium antennatum (Carlier, 1835), Sciapus bellus (Loew, 1873), S. euchromus (Loew, 1857), S. longulus (Fallén, 1823), S. tenuinervis (Loew, 1857), Syntormon triangulipes Becker, 1902, Teuchophorus calcaratus (Macquart, 1828), Thinophilus quadrimaculatus Becker, 1902, Trigonocera rivosa Becker, 1902, Xanthochlorus silaceus Chandler et Negrobov, 2008
Measurement of light mesons at RHIC by the PHENIX experiment
The PHENIX experiment at RHIC has measured a variety of light neutral mesons
(, K, , , , ) via
multi-particle decay channels over a wide range of transverse momentum. A
review of the recent results on the production rates of light mesons in p+p and
their nuclear modification factors in d+Au, Cu+Cu and Au+Au collisions at
different energies is presented.Comment: 5 pages, 4 figures, talk given at Hard Probes 2008 conference in La
Toja, Spain. submitted to EPJ
Construction and Expected Performance of the Hadron Blind Detector for the PHENIX Experiment at RHIC
A new Hadron Blind Detector (HBD) for electron identification in high density
hadron environment has been installed in the PHENIX detector at RHIC in the
fall of 2006. The HBD will identify low momentum electron-positron pairs to
reduce the combinatorial background in the mass spectrum, mainly
in the low-mass region below 1 GeV/c. The HBD is a windowless
proximity-focusing Cherenkov detector with a radiator length of 50 cm, a CsI
photocathode and three layers of Gas Electron Multipliers (GEM). The HBD uses
pure CF as a radiator and a detector gas. Construction details and the
expected performance of the detector are described.Comment: QM2006 proceedings, 4 pages 3 figure
A Hadron Blind Detector for the PHENIX Experiment
A novel Hadron Blind Detector (HBD) has been developed for an upgrade of the
PHENIX experiment at RHIC. The HBD will allow a precise measurement of
electron-positron pairs from the decay of the light vector mesons and the
low-mass pair continuum in heavy-ion collisions. The detector consists of a 50
cm long radiator filled with pure CF4 and directly coupled in a windowless
configuration to a triple Gas Electron Multiplier (GEM) detector with a CsI
photocathode evaporated on the top face of the first GEM foil.Comment: 4 pages, 3 figures, Quark Matter 2005 conference proceeding
Design, Construction, Operation and Performance of a Hadron Blind Detector for the PHENIX Experiment
A Hadron Blind Detector (HBD) has been developed, constructed and
successfully operated within the PHENIX detector at RHIC. The HBD is a
Cherenkov detector operated with pure CF4. It has a 50 cm long radiator
directly coupled in a window- less configuration to a readout element
consisting of a triple GEM stack, with a CsI photocathode evaporated on the top
surface of the top GEM and pad readout at the bottom of the stack. This paper
gives a comprehensive account of the construction, operation and in-beam
performance of the detector.Comment: 51 pages, 39 Figures, submitted to Nuclear Instruments and Method
Quadrupole Anisotropy in Dihadron Azimuthal Correlations in Central Au Collisions at =200 GeV
The PHENIX collaboration at the Relativistic Heavy Ion Collider (RHIC)
reports measurements of azimuthal dihadron correlations near midrapidity in
Au collisions at =200 GeV. These measurements
complement recent analyses by experiments at the Large Hadron Collider (LHC)
involving central Pb collisions at =5.02 TeV, which
have indicated strong anisotropic long-range correlations in angular
distributions of hadron pairs. The origin of these anisotropies is currently
unknown. Various competing explanations include parton saturation and
hydrodynamic flow. We observe qualitatively similar, but larger, anisotropies
in Au collisions compared to those seen in Pb collisions at the
LHC. The larger extracted values in Au collisions at RHIC are
consistent with expectations from hydrodynamic calculations owing to the larger
expected initial-state eccentricity compared with that from Pb
collisions. When both are divided by an estimate of the initial-state
eccentricity the scaled anisotropies follow a common trend with multiplicity
that may extend to heavy ion data at RHIC and the LHC, where the anisotropies
are widely thought to arise from hydrodynamic flow.Comment: 375 authors, 7 pages, 5 figures. Published in Phys. Rev. Lett. v2 has
minor changes to text and figures in response to PRL referee suggestions.
Plain text data tables for the points plotted in figures for this and
previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
Charged hadron multiplicity fluctuations in Au+Au and Cu+Cu collisions from sqrt(s_NN) = 22.5 to 200 GeV
A comprehensive survey of event-by-event fluctuations of charged hadron
multiplicity in relativistic heavy ions is presented. The survey covers Au+Au
collisions at sqrt(s_NN) = 62.4 and 200 GeV, and Cu+Cu collisions sqrt(s_NN) =
22.5, 62.4, and 200 GeV. Fluctuations are measured as a function of collision
centrality, transverse momentum range, and charge sign. After correcting for
non-dynamical fluctuations due to fluctuations in the collision geometry within
a centrality bin, the remaining dynamical fluctuations expressed as the
variance normalized by the mean tend to decrease with increasing centrality.
The dynamical fluctuations are consistent with or below the expectation from a
superposition of participant nucleon-nucleon collisions based upon p+p data,
indicating that this dataset does not exhibit evidence of critical behavior in
terms of the compressibility of the system. An analysis of Negative Binomial
Distribution fits to the multiplicity distributions demonstrates that the heavy
ion data exhibit weak clustering properties.Comment: 464 authors from 60 institutions, 17 pages, 12 figures, 1 table.
Submitted to Physical Review C. Plain text data tables for the points plotted
in figures for this and previous PHENIX publications are (or will be)
publicly available at http://www.phenix.bnl.gov/papers.htm
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