31 research outputs found
System Size and Energy Dependence of Jet-Induced Hadron Pair Correlation Shapes in Cu+Cu and Au+Au Collisions at sqrt(s_NN) = 200 and 62.4 GeV
We present azimuthal angle correlations of intermediate transverse momentum
(1-4 GeV/c) hadrons from {dijets} in Cu+Cu and Au+Au collisions at sqrt(s_NN) =
62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is
broadened, non-Gaussian, and peaked away from \Delta\phi=\pi in central and
semi-central collisions in all the systems. The broadening and peak location
are found to depend upon the number of participants in the collision, but not
on the collision energy or beam nuclei. These results are consistent with sound
or shock wave models, but pose challenges to Cherenkov gluon radiation models.Comment: 464 authors from 60 institutions, 6 pages, 3 figures, 2 tables.
Submitted to Physical Review Letters. 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
Improved Measurement of Double Helicity Asymmetry in Inclusive Midrapidity pi^0 Production for Polarized p+p Collisions at sqrt(s)=200 GeV
We present an improved measurement of the double helicity asymmetry for pi^0
production in polarized proton-proton scattering at sqrt(s) = 200 GeV employing
the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The
improvements to our previous measurement come from two main factors: Inclusion
of a new data set from the 2004 RHIC run with higher beam polarizations than
the earlier run and a recalibration of the beam polarization measurements,
which resulted in reduced uncertainties and increased beam polarizations. The
results are compared to a Next to Leading Order (NLO) perturbative Quantum
Chromodynamics (pQCD) calculation with a range of polarized gluon
distributions.Comment: 389 authors, 4 pages, 2 tables, 1 figure. Submitted to Phys. Rev. D,
Rapid Communications. 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
Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration
Extensive experimental data from high-energy nucleus-nucleus collisions were
recorded using the PHENIX detector at the Relativistic Heavy Ion Collider
(RHIC). The comprehensive set of measurements from the first three years of
RHIC operation includes charged particle multiplicities, transverse energy,
yield ratios and spectra of identified hadrons in a wide range of transverse
momenta (p_T), elliptic flow, two-particle correlations, non-statistical
fluctuations, and suppression of particle production at high p_T. The results
are examined with an emphasis on implications for the formation of a new state
of dense matter. We find that the state of matter created at RHIC cannot be
described in terms of ordinary color neutral hadrons.Comment: 510 authors, 127 pages text, 56 figures, 1 tables, LaTeX. Submitted
to Nuclear Physics A as a regular article; v3 has minor changes in response
to referee comments. 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
J/psi Production and Nuclear Effects for d+Au and p+p Collisions at sqrt(s_NN) = 200 GeV
J/psi production in d+Au and p+p collisions at sqrt(s_NN) = 200 GeV has been
measured by the PHENIX experiment at rapidities -2.2 < y < +2.4. The cross
sections and nuclear dependence of J/\psi production versus rapidity,
transverse momentum, and centrality are obtained and compared to lower energy
p+A results and to theoretical models. The observed nuclear dependence in d+Au
collisions is found to be modest, suggesting that the absorption in the final
state is weak and the shadowing of the gluon distributions is small and
consistent with Dokshitzer-Gribov-Lipatov-Altarelli-Parisi-based
parameterizations that fit deep-inelastic scattering and Drell-Yan data at
lower energies.Comment: 331 authors, 6 pages text, 3 figures. Published in PRL. Version 2 has
minor changes required during the review and production process. Of
significant note are that (a) the original Figs. 3 and 4 are combined into a
single Fig. 3 and (b) the value of (p_T)**2 at x_F=0 changed from 3.17+/-0.33
to 3.03+/-0.40. Plain text data tables for the points plotted in figures for
this and previous PHENIX publications are publicly available at
http://www.phenix.bnl.gov/papers.htm
Saturation of azimuthal anisotropy in Au + Au collisions at sqrt(s_NN) = 62 - 200 GeV
New measurements are presented for charged hadron azimuthal correlations at
mid-rapidity in Au+Au collisions at sqrt(s_NN) = 62.4 and 200 GeV. They are
compared to earlier measurements obtained at sqrt(s_NN) = 130 GeV and in Pb+Pb
collisions at sqrt(s_NN) = 17.2 GeV. Sizeable anisotropies are observed with
centrality and transverse momentum (p_T) dependence characteristic of elliptic
flow (v_2). For a broad range of centralities, the observed magnitudes and
trends of the differential anisotropy, v_2(p_T), change very little over the
collision energy range sqrt(s_NN) = 62-200 GeV, indicating saturation of the
excitation function for v_2 at these energies. Such a saturation may be
indicative of the dominance of a very soft equation of state for sqrt(s_NN) =
62-200 GeV.Comment: 432 authors, 7 pages text, 4 figures, REVTeX4. To be submitted to
Physical Review Letters. 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
Cyclotron resonance stydy in InAs/AlSb quantum well heterostructures with two occupied electronic subbands
International audienc
Cyclotron resonance of 2D holes in strained InGaAs/GaAs quantum wells in quantizing magnetic fields
International audienc
New Cu4Na4-and Cu5-based phenylsilsesquioxanes. Synthesis via complexation with 1,10-phenanthroline, structures and high catalytic activity in Alkane oxidations with peroxides in acetonitrile
Self-assembly of copper(II)phenylsilsesquioxane assisted by the use of 1,10-phenanthroline (phen) results in isolation of two unusual cage-like compounds: (PhSiO1,5)12 (CuO)4 (NaO0.5)4 (phen)4 1 and (PhSiO1,5)6 (PhSiO1,5)7 (HO0.5)2 (CuO)5 (O0.25)2 (phen)3 2. X-Ray diffraction study revealed extraordinaire molecular architectures of both products. Namely, complex 1 includes single cyclic (PhSiO1,5)12 silsesquioxane ligand. Four sodium ions of 1 are additionally ligated by 1,10-phenan throlines. In turn, “sodium-less” complex 2 represents coordination of 1,10-phenanthrolines to copper ions. Two silsesquioxane ligands of 2 are: (i) noncondensed cubane of a rare Si6-type and (ii) unprecedented Si7-based ligand including two HOSiO1.5 fragments. These silanol units were formed due to removal of phenyl groups from silicon atoms, observed in mild conditions. The presence of phenanthroline ligands in products 1 and 2 favored the π–π stacking interactions between neighboring cages. Noticeable that in the case of 1 all four phenanthrolines participated in such supramolecular organization, unlike to complex 2 where one of the three phenanthrolines is not “supramolecularly active”. Complexes 1 and 2 were found to be very efficient precatalysts in oxidations with hydroperoxides. A new method for the determination of the participation of hydroxyl radicals has been developed. © 2019 by the authors. Licensee MDPI, Basel, Switzerland