36184613
Reexamining the Fritzsch-Stech SO(10) model of quarks and leptons.
In a rather predictive model of the quark and lepton mass matrices we discuss restrictions on the quark and lepton mixings implied by two different phenomena: (1) the Mikheyev-Smirnov-Wolfenstein explanation of the solar-neutrino problem and (2) the recent ARGUS measurements of BB-bar mixing and of charmless B decays involving baryons. We conclude that the model allows for neutrino masses and mixings which may account for matter oscillations of either of the two types ..nu../sub e/ to ..nu../sub ..mu../ or ..nu../sub e/ to ..nu../sub tau/. In the quark sector the phenomenology of the model is identical to that of the Fritzsch quark matrix. Within our scheme the simplest interpretation of the recent ARGUS results suggests a large value of m/sub t/ around 80 GeV. The model predicts chemically bondU/sub u//sub b/chemically bond to be around 0.0032
181733866
LASER WELDING OF STEEL PLATES WITH UNMACHINED EDGES
91179466
Beam commissioning of the PEP-II High Energy Ring
The PEP-II High Energy Ring (HER), a 9 GeV electron storage ring, has been in commissioning since spring 1997. Initial beam commissioning activities focused on systems checkout and commissioning and on determining the behaviour of the machine systems at high beam currents, This phase culminated with the accumulation of 0.75 A of stored beam-sufficient to achieve design luminosity-in January 1998 after 3.5 months of beam time. Collisions with the 3 GeV positron beam of the Low Energy Ring (LER) were achieved in Summer of 1998. At high beam currents, collective instabilities have been seen. Since then, commissioning activities for the HER have shifted in focus towards characterization of the machine and a rigorous program to understand the machine and the beam dynamics is presently underway.
122953784
A hamiltonian structure from gauge transformations of the Zakharov-Shabat system
Abstract We study a hamiltonian structure for nonlinear evolution equations arising from a class of gauge transformations of the Zakharov-Shabat system.
119337087
Investigating the process of star formation in young LMC star clusters
The rich star clusters in the Large Magellanic Cloud (LMC) are ideal for studying the process of star formation. Here we focus on the determination of age spreads amongst the massive stars in two young clusters, NGC1818 and NGC1805. We present colour magnitude diagrams (derived from HST data) for these clusters, and discuss the difficulties in age spread determination.
18232712
Chandra observations of the nearby spiral galaxy NGC6503
We have observed the nearby spiral galaxy NGC6503 using Chandra. Seven discrete sources associated with the galaxy have been found, one of them coincident with its Liner-starburst nucleus. One of the sources corresponds to a ULX with Lx >~ 10e39 ergs/s. Previous ROSAT observations of the galaxy show that this source has varied by at least a factor 3 in the last 6 years. No evidence is found for strong diffuse emission in the nuclear region or the presence of a low luminosity AGN.
54066498
OO design and implementation: Java and Java analysis studio
We present an overview of the Java language, Java virtual machine, and the large set of standard libraries and extensions available for Java, and provide a discussion of issues that effect Java performance. This is followed by an introduction to Java Analysis Studio (JAS), a tool written in Java, and in which Java is the language used to perform data analysis. We will also explore how OO techniques have been used to built a system from modular components including visualization, fitting and data-access components that can be used together, or on their own.
30886954
Experimental investigation of nonlinear dynamics in the Fermilab Tevatron.
The nonlinear dynamics of transverse particle oscillations in the Tevatron is studied experimentally and compared with prediction. Accurate measurements of various phase-space features are obtained. A theoretically expected metastable state of the accelerator, with particles captured on nonlinear resonance islands, is demonstrated experimentally, and stability of the state is investigated.
36028712
Driven response of a trapped particle beam.
The dynamics of a metastable beam of particles injected'' into artificially excited resonance islands in the Fermilab Tevatron is studied. Evolution of the captured beam distribution is measured by an externally detectable coherent signal. Dynamical partitions observed in the control space of amplitude and tune of a focusing modulation are consistent with an equivalent mode of an ensemble of driven gravity pendula. The model's single parameter, the island tune {ital Q}{sub {ital I}} of small oscillations, is inferred as the central frequency of resonant detrapping under this weak drive.
26932934
Measurements of a Hamiltonian system and their description by a diffusive model.
The dynamics of transverse particle oscillations in the Fermilab Tevatron, artificially made nonlinear, is studied by observing beam profiles over periods up to an hour. A ``diffusive'' model with amplitude-dependent diffusion coefficient gives a quantitatively accurate description of beam evolution. The evolution is influenced strongly by nonlinear resonance.
117445639
A new collider upgrade proposal: Increasing the pbar-p collider energy