23 research outputs found
The Surprising Transparency of the sQGP at LHC
We present parameter-free predictions of the nuclear modification factor,
R_{AA}^pi(p_T,s), of high p_T pions produced in Pb+Pb collisions at
sqrt{s}_{NN}=2.76 and 5.5 ATeV based on the WHDG/DGLV
(radiative+elastic+geometric fluctuation) jet energy loss model. The initial
quark gluon plasma (QGP) density at LHC is constrained from a rigorous
statistical analysis of PHENIX/RHIC pi^0 quenching data at sqrt{s}_{NN}=0.2
ATeV and the charged particle multiplicity at ALICE/LHC at 2.76 ATeV. Our
perturbative QCD tomographic theory predicts significant differences between
jet quenching at RHIC and LHC energies, which are qualitatively consistent with
the p_T-dependence and normalization---within the large systematic
uncertainty---of the first charged hadron nuclear modification factor,
R^{ch}_{AA}, data measured by ALICE. However, our constrained prediction of the
central to peripheral pion modification, R^pi_{cp}(p_T), for which large
systematic uncertainties associated with unmeasured p+p reference data cancel,
is found to be over-quenched relative to the charged hadron ALICE R^{ch}_{cp}
data in the range 5<p_T<20 GeV/c. The discrepancy challenges the two most basic
jet tomographic assumptions: (1) that the energy loss scales linearly with the
initial local comoving QGP density, rho_0, and (2) that \rho_0 \propto
dN^{ch}(s,C)/dy is proportional to the observed global charged particle
multiplicity per unit rapidity as a function of sqrt{s} and centrality class,
C. Future LHC identified (h=pi,K,p) hadron R^h_{AA} data (together with precise
p+p, p+Pb, and Z boson and direct photon Pb+Pb control data) are needed to
assess if the QGP produced at LHC is indeed less opaque to jets than predicted
by constrained extrapolations from RHIC.Comment: 13 pages, 8 figure
Experimental and Theoretical Challenges in the Search for the Quark Gluon Plasma: The STAR Collaboration's Critical Assessment of the Evidence from RHIC Collisions
We review the most important experimental results from the first three years
of nucleus-nucleus collision studies at RHIC, with emphasis on results from the
STAR experiment, and we assess their interpretation and comparison to theory.
The theory-experiment comparison suggests that central Au+Au collisions at RHIC
produce dense, rapidly thermalizing matter characterized by: (1) initial energy
densities above the critical values predicted by lattice QCD for establishment
of a Quark-Gluon Plasma (QGP); (2) nearly ideal fluid flow, marked by
constituent interactions of very short mean free path, established most
probably at a stage preceding hadron formation; and (3) opacity to jets. Many
of the observations are consistent with models incorporating QGP formation in
the early collision stages, and have not found ready explanation in a hadronic
framework. However, the measurements themselves do not yet establish
unequivocal evidence for a transition to this new form of matter. The
theoretical treatment of the collision evolution, despite impressive successes,
invokes a suite of distinct models, degrees of freedom and assumptions of as
yet unknown quantitative consequence. We pose a set of important open
questions, and suggest additional measurements, at least some of which should
be addressed in order to establish a compelling basis to conclude definitively
that thermalized, deconfined quark-gluon matter has been produced at RHIC.Comment: 101 pages, 37 figures; revised version to Nucl. Phys.
The Concise Guide to PHARMACOLOGY 2023/24: Ion channels.
The Concise Guide to PHARMACOLOGY 2023/24 is the sixth in this series of biennial publications. The Concise Guide provides concise overviews, mostly in tabular format, of the key properties of approximately 1800 drug targets, and over 6000 interactions with about 3900 ligands. There is an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (https://www.guidetopharmacology.org/), which provides more detailed views of target and ligand properties. Although the Concise Guide constitutes almost 500 pages, the material presented is substantially reduced compared to information and links presented on the website. It provides a permanent, citable, point-in-time record that will survive database updates. The full contents of this section can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.16178. Ion channels are one of the six major pharmacological targets into which the Guide is divided, with the others being: G protein-coupled receptors, nuclear hormone receptors, catalytic receptors, enzymes and transporters. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. The landscape format of the Concise Guide is designed to facilitate comparison of related targets from material contemporary to mid-2023, and supersedes data presented in the 2021/22, 2019/20, 2017/18, 2015/16 and 2013/14 Concise Guides and previous Guides to Receptors and Channels. It is produced in close conjunction with the Nomenclature and Standards Committee of the International Union of Basic and Clinical Pharmacology (NC-IUPHAR), therefore, providing official IUPHAR classification and nomenclature for human drug targets, where appropriate
Heavy-flavor production and medium properties in high-energy nuclear collisions --What next?
Open and hidden heavy-flavor physics in high-energy nuclear collisions are entering a new and exciting stage towards reaching a clearer understanding of the new experimental results with the possibility to link them directly to the advancement in lattice Quantum Chromo-Dynamics (QCD). Recent results from experiments and theoretical developments regarding open and hidden heavy-flavor dynamics have been debated at the Lorentz Workshop Tomography of the Quark-Gluon Plasma with Heavy Quarks, which was held in October 2016 in Leiden, The Netherlands. In this contribution, we summarize identified common understandings and developed strategies for the upcoming five years, which aim at achieving a profound knowledge of the dynamical properties of the quark-gluon plasma
Application of Mechanochemistry in Ferrite Materials Technology
An overview of progress and implications of recent technological advances in mechanochemical processing of ferrites is presented. We discuss the potential for applications of mechanical activation by induced phase transformations and chemical reactions in soft and hard ferrite materials through enhancement of structural and magnetic properties
XRD and HREM Studies of Structural Phases in Non-Stoichiometric Complex Iron Oxides
The influence of prolonged ball milling on structural changes of hexagonal and spinel type complex iron oxides
has been studied by x-ray diffraction and high resolution electron microscopy. The XRD and HREM results for ball milled
SrFe12O19 ferrite show fast decomposition and formation of Fe2O3 and SrO simple oxides. Microstructural developments for
a powder mixture of Co(OH)2 and Fe2O3 show the formation of cubic type structure (spinel). By comparison with the XRD
results, HREM analysis confirmed local phase separation, with magnetic Fe3O4 and CoFe2O4 nanosize (10-30 nm) particles
being formed
IR Studies of the Phase Transformation of Fe2O3 → Fe3O4by Magnetomechanical Activation
The phase transformation of hematite αFe2O3 into magnetite Fe3O4 during wet milling in vacuum as a result of mechanochemical process has been investigated by infrared spectroscopy. The FTIR spectra were recorded in the wavenumber range kom 400 to 4000 cm-1. Two very strong bands were generally observed : one in the range 557-577cm-1 with shoulders in 632-693 cm-1, the other at about 475 cm-1. The most important feature is a very strong dependence of the intensities of the main absorption bands on the milling time of the sample. In addition, there was a broad band in the 3000-3700 cm-1 region related to the appearance of a certain number of OH groups in the spinel lattice. The results are discussed assuming the theoretically indicated active IR modes for ferites. A little disorded was interpreted as generated by ball milling and no traces of amorphization were observed
Formation of titanium nitrides via wet reaction ball milling
10.1016/S0925-8388(00)00822-7Journal of Alloys and Compounds3071-2249-253JALC
Mechanochemical Treatment of SrFe<sub>12</sub>O<sub>19</sub> - Microstructural Investigation by Neutron Diffraction
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