20,634 research outputs found
Thermalization at RHIC
Ideal hydroynamics provides an excellent description of all aspects of the
single-particle spectra of all hadrons with transverse momenta below about
1.5-2 GeV/c at RHIC. This is shown to require rapid local thermalization at a
time scale below 1 fm/c and at energy densities which exceed the critical value
for color deconfinement by an order of magnitude. The only known thermalized
state at such energy densities is the quark-gluon plasma (QGP). The rapid
thermalization indicates that the QGP is a strongly interacting liquid rather
than the weakly interacting gas of quarks and gluons that was previously
expected.Comment: Erroneous formulation on p.2 corrected. 16 pages, incl. 4 postscript
figures. Invited talk presented at HADRON-RANP 2004 (IX Hadron Physics and
VII Relativistics Aspects of Nuclear Physics: A Joint Meeting on QCD and
QGP), Angra dos Reis, Rio de Janeiro, Brazil, March 28 - April 3, 2004. To
appear in AIP Conference Proceedings (M. Bracco, M. Chiapparini, et al.,
eds.
"The land of my dreams": the gendered utopian dreams and disenchantment of British literary ex-combatants of the Great War
The last two decades have seen a slow shift in the academic understanding of the impact of the Great War on concepts of gender in interwar Britain. The work of a small group of cultural historians, following in the footsteps of Rosa Maria Bracco, has challenged existing interpretations of the cultural impact of the Great War on concepts of gender. The argument that the wartime advances made by women in Great War in Britain, allied to combatant trauma, resulted in a crisis of masculinity and a related heightening of misogyny, has been questioned by one that challenges the notion of a crisis of masculinity, stresses continuity in gender constructs, and develops a more complex picture of cultural responses to the war
vertex from QCD sum rules
The form factors and the coupling constant of the vertex are
calculated using the QCD sum rules method. Three point correlation functions
are computed considering both and mesons off-shell and, after an
extrapolation of the QCDSR results, we obtain the coupling constant of the
vertex. We study the uncertainties in our result by calculating a third form
factor obtained when the is the off-shell meson, considering other
acceptable structures and computing the variations of the sum rules'
parameters. The form factors obtained have different behaviors but their
simultaneous extrapolations reach to the same value of the coupling constant
. We compare our result with other theoretical
estimates.Comment: 11 pages, 11 figure
Compilation of Giant Electric Dipole Resonances Built on Excited States
Giant Electric Dipole Resonance (GDR) parameters for gamma decay to excited
states with finite spin and temperature are compiled. Over 100 original works
have been reviewed and from some 70 of which more than 300 parameter sets of
hot GDR parameters for different isotopes, excitation energies, and spin
regions have been extracted. All parameter sets have been brought onto a common
footing by calculating the equivalent Lorentzian parameters. The current
compilation is complementary to an earlier compilation by Samuel S. Dietrich
and Barry L. Berman (At. Data Nucl. Data Tables 38(1988)199-338) on
ground-state photo-neutron and photo-absorption cross sections and their
Lorentzian parameters. A comparison of the two may help shed light on the
evolution of GDR parameters with temperature and spin. The present compilation
is current as of January 2006.Comment: 31 pages including 1 tabl
A Pedagogical Discussion Concerning the Gravitational Energy Radiated by Keplerian Systems
We first discuss the use of dimensional arguments (and of the quadrupolar
emission hypothesis) in the derivation of the gravitational power radiated on a
circular orbit. Then, we show how to simply obtain the instantaneous power
radiated on a general Keplerian orbit by approximating it locally by a circle.
This allows recovering with a good precision, in the case of an ellipse, the
highly non trivial dependence on the eccentricity of the average power given by
general relativity. The whole approach is understandable by undergraduate
students.Comment: A simpler method has been used in the calculations, which requires
now only standard knowledge (the radius of curvature is defined by the normal
acceleration). Two figures have been added. Concerning the dimensional
analysis, the comparison with electromagnetism has been detaile
Experimental investigation of the mooring system of a wave energy converter in operating and extreme wave conditions
A proper design of the mooring systems for Wave Energy Converters (WECs) requires an accurate investigation of both operating and extreme wave conditions. A careful analysis of these systems is required to design a mooring configuration that ensures station keeping, reliability, maintainability, and low costs, without affecting the WEC dynamics. In this context, an experimental campaign on a 1:20 scaled prototype of the ISWEC (Inertial Sea Wave Energy Converter), focusing on the influence of the mooring layout on loads in extreme wave conditions, is presented and discussed. Two mooring configurations composed of multiple slack catenaries with sub-surface buoys, with or without clump-weights, have been designed and investigated experimentally. Tests in regular, irregular, and extreme waves for a moored model of the ISWEC device have been performed at the University of Naples Federico II. The aim is to identify a mooring solution that could guarantee both correct operation of the device and load carrying in extreme sea conditions. Pitch motion and loads in the rotational joint have been considered as indicators of the device hydrodynamic behavior and mooring configuration impact on the WEC
Strong decay of the heavy tensor mesons with QCD sum rules
In the article, we calculate the hadronic coupling constants ,
, , with the three-point QCD
sum rules, then study the two body strong decays ,
, , , and make
predictions to be confronted with the experimental data in the future.Comment: 12 pages, 2 figure
Two-year observations of the Jupiter polar regions by JIRAM on board Juno
We observed the evolution of Jupiter's polar cyclonic structures over two years between February 2017 and February 2019, using polar observations by the Jovian InfraRed Auroral Mapper, JIRAM, on the Juno mission. Images and spectra were collected by the instrument in the 5âÎŒm wavelength range. The images were used to monitor the development of the cyclonic and anticyclonic structures at latitudes higher than 80° both in the northern and the southern hemispheres. Spectroscopic measurements were then used to monitor the abundances of the minor atmospheric constituents water vapor, ammonia, phosphine and germane in the polar regions, where the atmospheric optical depth is less than 1. Finally, we performed a comparative analysis with oceanic cyclones on Earth in an attempt to explain the spectral characteristics of the cyclonic structures we observe in Jupiter's polar atmosphere
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