11984264
Low-energy technicolor Lagrangian with vector mesons.
We apply techniques used in QCD and the implied chiral symmetry to motivate a low-energy Lagrangian for technicolor theories. This allows one to cleanly introduce the gluon and the weak gauge bosons at the technifermion level. The Higgs mechanism and techni-vector-meson dominance are displayed. The effect of vector dominance on the {ital W} and {ital Z} masses, the techni-{omega} and techni-{rho} couplings, and the sizable enhancement by the latter on {ital W} and {ital Z} production are demonstrated. Differences between our results and some published results are discussed. The incorporation of extended technicolor interactions is also presented.
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.
181733866
LASER WELDING OF STEEL PLATES WITH UNMACHINED EDGES
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.
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.
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.
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.
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.
31307451
Double analog state in odd-A nuclei.
Measurements were performed using pion double charge exchange to observe the double isobaric analog state (DIAS) in the odd-[ital A] nuclei [sup 54]V, [sup 59]Co, [sup 115]In, and [sup 197]Au. These results are combined with data for other odd-[ital A] targets and used to investigate the [ital N], [ital Z], and [ital A] dependence of DIAS cross sections.
117445639
A new collider upgrade proposal: Increasing the pbar-p collider energy
32539092
Measurement of the mass of the tau lepton.
The mass of the [tau] lepton has been measured at the Beijing Electron-Positron Collider using the Beijing Spectrometer. A search near threshold for [ital e][sup +][ital e[minus]][r arrow][tau][sup +][tau][sup [minus]] was performed. Candidate events were identified by requiring that one [tau] decay via [tau][r arrow][ital e][nu][bar [nu]], and the other via [tau][r arrow][mu][nu][bar [nu]]. The mass value, obtained from a fit to the energy dependence of the [tau][sup +][tau][sup [minus]] cross section, is [ital m][sub [tau]]=1776.9[sub [minus]0.5][sup +0.4][plus minus]0.2 MeV.