1,249 research outputs found
Can Recent Charge Fluctuations Be a Reliable signal for a QGP at RHIC?
The recent papers of Jeon and Koch [1] and Asakawa, Heinz, and Muller [2]
argue that the event by event fluctuations of the ratio of the positively
charged and negatively charged pions provide a distinct signal for a QGP at
RHIC/LHC due to differences in those from the QGP phase and the Hadron Gas
Phase.In this paper we point out that aside from the questionability of the
many assumptions in the treatment used,even following their approach there are
other effects not considered, e.g. color charge fluctuations, which could
significantly or even completely wash out the proposed signal.Therefore lack of
observation of these charge fluctuation signals cannot lead one to conclude
that a QGP is not formed at RHIC. A general discussion of experimental
requirements for observation of such signals(if they exist),annd how to
interpret them is included.Comment: 9 pages and 2 Fig
The Centrality Dependence of the Parton Bubble Model for high energy heavy ion collisions and fireball surface substructure at RHIC
In an earlier paper we developed a QCD inspired theoretical parton bubble
model (PBM) for RHIC/LHC. The PBM quantitatively agreed with the strong charged
particle pair correlations observed by the STAR collaboration at RHIC in the
highest energy Au + Au central collisions, and also agreed with the Hanbury
Brown and Twiss (HBT) observed small final state source size approximately 2f
radii in the transverse momentum range above 0.8 GeV/c. The model assumed a
substructure of a ring of localized adjoining 2f radius bubbles(gluonic hot
spots) perpendicular to the collider beam direction, centered on the beam, at
mid-rapidity and located on the expanding fireball surface of the Au + Au
collisions. In this paper we extend the model (PBME) to include the changing
development of bubbles with centrality from the most central region where
bubbles are very important to the most peripheral where the bubbles are gone.
Energy density is found to be related to bubble formation and as centrality
decreases the maximum energy density and bubbles shift from symmetry around the
beam axis to the reaction plane region causing a strong correlation of bubble
formation with elliptic flow. We obtained reasonably quantitative agreement
(within a few percent of the total correlations) with a new precision RHIC
experiment which extended the centrality region investigated to the range 0-80%
(most central to most peripheral). The characteristics and behavior of the
bubbles imply they represent a significant substructure formed on the surface
of the fireball at kinetic freezeoutComment: ACCEPTED for publication in Phys. Rev. C. minor referee changes.20
pages, 12 figures, 3 table
Evidence for a 4th state related to the three JPC = 2++, pi- p -> phi phi n states explainable by 2++ Glueball production
Four separate experiments, observing the OZI forbidden disconnected reaction
pi- p -> phi phi n with increasing statistics were consistent. These
experiments very selectively completely broke down the OZI suppression by 3 phi
phi resonances with IG JPC = 0+ 2++ in the observed mass region 2.038 to 2.600
GeV. The only viable proposed explanation has been that the IG JPC = 0+ 2++
Glueball expected in this mass region caused the hard glue in the disconnection
to resonate and very selectively breakdown the OZI suppression for its quantum
numbers only. Recently a p p central production spin analysis found the
f2(1950) had a dominant decay mode f2(1270) pi pi. We consider if it is related
to the phi phi resonances, and find that it likely is.Comment: 9 pages, 3 figure
HIGH ENERGY ELASTIC SCATTERING OF , p,/anti p/ AND K BY PROTONS (AND REGGE POLE PREDICTIONS)
The counter hodoscope experiments at incident particle momenta of 7-20 Bev/c are summarized. The data are presented, together with the associated Regge pole analyses. The effective radii, opacities, and total cross sections obtained for the interactions are included. A magnetic spectrometer setup used for low four-momentum transfer data is also described, and optical theorem predictions for pi /sup -/-p and p-p are given. (D.C.W.
Understanding kuru: the contribution of anthropology and medicine
To understand kuru and solve the problems of its cause and transmission required the integration of knowledge from both anthropological and medical research. Anthropological studies elucidated the origin and spread of kuru, the local mortuary practices of endocannibalism, the social effects of kuru, the life of women and child-rearing practices, the kinship system of the Fore and their willingness to incorporate outsiders into it, the myths, folklore and history of the Fore and their neighbours, sorcery as a powerful social phenomenon and way of explaining the causation of disease, and concepts of the treatment of disease. Many scientists from different disciplines, government officers and others have contributed to this chapter of medical history but it is the Fore people who have contributed the most, through their suffering, their cooperative and reliable witness to kuru, and their participation, in various ways, in the research process itself
Exploring a rheonomic system
A simple and illustrative rheonomic system is explored in the Lagrangian
formalism. The difference between Jacobi's integral and energy is highlighted.
A sharp contrast with remarks found in the literature is pointed out. The
non-conservative system possess a Lagrangian not explicitly dependent on time
and consequently there is a Jacobi's integral. The Lagrange undetermined
multiplier method is used as a complement to obtain a few interesting
conclusion
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Hadronic production of glueballs
Local Gauge Invariance of SU(3)/sub c/ and color confinement would require that the only hadrons in the world be glueballs. However, when we add the quarks and obtain QCD it is experimentally clear that quark built states mask the expected glueballs. Thus discovery of glueballs is essential for the viability of QCD. Papers presented at the 1983 International Europhysics Conference on High Energy Physics on the hadronic production of glueballs and searches for glueballs are reviewed. (WHK
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