2,186 research outputs found
Isosinglet Scalar Mesons Below 2 GeV and the Scalar Glueball Mass
A collective treatment of the I=0 scalar mesons below 2 GeV [sigma (550),
f0(980), f0(1370), f0(1500) and f0(1710)] in a non-linear chiral Lagrangian
framework that is constrained by the mass and the partial decay widths of the
I=1/2,1 scalars [kappa(900), K0*(1430), a0(980) and a0(1450)] is presented. The
sub-structure of these states in terms of two and four quark components, as
well as a glueball component is explored, and its correlation with the mass of
f0(1370) is studied. Consistency with the available experimental data suggests
that the sigma(550) is dominantly a non-strange four-quark state, whereas the
sub-structure of other I=0 states are sensitive to the input mass of f0(1370).
This investigation estimates the scalar glueball mass in the range 1.47--1.64
GeV.Comment: 12 pages, revtex, 2 figs; numerical work updated, typos corrected,
refs adde
Lowest-Lying Scalar Mesons and a Possible Probe of Their Quark Substructure
In this talk, an overview of the status of the light scalar mesons in the
context of the non linear chiral Lagrangian of references [1-3] is presented.
The evidence for the existence of a scalar nonet below 1 GeV is reviewed, and
it is shown that by introducing a scalar nonet an indirect way of probing the
quark substructure of these scalars through the scalar mixing angle can be
obtained. It is then reviewed that consistency of this non-linear chiral
Lagrangian framework with the experimental data on pi pi and pi K scattering,
as well as the decay eta' to eta pi pi, results in a range for the mixing angle
which indicates that the quark substructure of these light scalars are closer
to a four quark picture.Comment: Talk given at 21st Annual MRST Conference: High Energy Physics at the
Millenium, Ottawa, Ontario, Canada, 10-12 May 1999, 8 page
AC vs. DC Boost Converters: A Detailed Conduction Loss Comparison
Studies have shown the efficiency benefits of DC dis- tribution systems are largely due to the superior performance of DC/DC converters. Nonetheless, these studies are often based on product data that differs widely in manufacturer and operating voltage. This work develops a rigorous loss model to theoretically compare the efficiency of a DC/DC and an AC/DC PFC boost converter. It ensures each converter has the same components and equivalent operating voltages. The results show AC boost converters below 500 W to have 2.9 to 4.2 times the loss of DC
- …