2,100 research outputs found
Chiral Symmetry and Scalars
The suggestion by Jaffe that if is a light state
then even the fundamental chiral transformation properties of the
becomes {\bf unclear}, has stimulated much interest. Adler pointed out
that in fact the seminal work on chiral symmetry via PCAC consistency, is
really quite consistent with the being predominantly
. This interpretation was actually backed by subsequent work
on effective Lagrangian methods for linear and non linear realizations. More
recent work of Achasov suggests that intermediate four-quark states determine
amplitudes involving other scalars and below 1 GeV,
and the report by Ning Wu that study on meson in continue to support a non with mass
as low as 390 MeV. It is also noted that more recent re-analysis of
scattering by S. Ishida {\em et al.} together with the work of the E791
Collaboration, support the existence of the scalar particle with
comparatively light mass as well.Comment: 4 pages, aipproc style file. Parallel session talk at Hadron
2001-Protvin
The Puzzle of J/\psi and \psi' Decays
The recent BES Collaboration data on \psi' \ra PV, particularly the isospin
violating mode \psi' \ra \pi^0 \omega^0 and finding of a finite number for
B(\psi' \ra K^{*0}\bar{K}^0), enable us now to deal more precisely about the
challenges to theory concerning this extraordinary and remarkable so called
Puzzle of and Decays. In terms of existing data,
and deploying the simplest phenomenology, measurement of \psi' \ra \pi^+\pi^-
and whether a finite number for the mode might require a
significantly larger accumulation of data, remain interesting questions.Comment: 9pages, added reference, typos, and very slight change in text, LATEX
forma
Aspects of Charmonium Physics
I review possible resolution of the
puzzle based on two inputs: the relative phase between the one- photon and the
gluonic decay amplitudes, and a possible hadronic excess in the inclusive
nonelectromagnetic decay rate of . The status of a universal
large phase here is examined for its meaning and implications (including those
for B-physics). Since the future of tau/charm facility(s) are again under
consideration together with a future anti-proton facility at GSI, I propose to
extend my review to include a broader discussion of charmonium physics.
Outstanding questions like the status of the state of charmonium,
measuring mixing and relative strong phases, status of
molecular P(S) - wave charmonia will also be discussed amongst others.Comment: 7 pages, aipproc style file. Plenary session talk at Hadron
2001-Protvin
Improvement of uncoupled Hartree-Fock expectation values for physical properties
Hartree-Fock calculation method as zero-order approximation for determining atomic and molecular second-order propertie
One-loop effective potential for SO(10) GUT theories in de Sitter space
Zeta-function regularization is applied to evaluate the one-loop effective
potential for SO(10) grand-unified theories in de Sitter cosmologies. When the
Higgs scalar field belongs to the 210-dimensional irreducible representation of
SO(10), attention is focused on the mass matrix relevant for the
SU(3)xSU(2)xU(1) symmetry-breaking direction, to agree with low-energy
phenomenology of the particle-physics standard model. The analysis is
restricted to those values of the tree-level-potential parameters for which the
absolute minima of the classical potential have been evaluated. As shown in the
recent literature, such minima turn out to be SO(6)xSO(4)- or
SU(3)xSU(2)xSU(2)xU(1)-invariant. Electroweak phenomenology is more naturally
derived, however, from the former minima. Hence the values of the parameters
leading to the alternative set of minima have been discarded. Within this
framework, flat-space limit and general form of the one-loop effective
potential are studied in detail by using analytic and numerical methods. It
turns out that, as far as the absolute-minimum direction is concerned, the
flat-space limit of the one-loop calculation about a de Sitter background does
not change the results previously obtained in the literature, where the
tree-level potential in flat space-time was studied. Moreover, when curvature
effects are no longer negligible in the one-loop potential, it is found that
the early universe remains bound to reach only the SO(6)xSO(4) absolute
minimum.Comment: 25 pages, plain Tex, plus Latex file of the tables appended at the
end. Published in Classical and Quantum Gravity, Vol. 11, pp. 2031-2044,
August 199
Elusive vector glueball
If the vector glueball exists in the mass range that theory suggests, its
resonance production cross section can be seen in e+e- annihilation only if the
decay width is very narrow (< a few MeV). Otherwise it willbe observed only
indirectly through its mixing with psi(2S). A few tests of the glueball-psi'
mixing are proposed for future charm factories.Comment: One misleading short sentence delete
A one-phase interior point method for nonconvex optimization
The work of Wachter and Biegler suggests that infeasible-start interior point
methods (IPMs) developed for linear programming cannot be adapted to nonlinear
optimization without significant modification, i.e., using a two-phase or
penalty method. We propose an IPM that, by careful initialization and updates
of the slack variables, is guaranteed to find a first-order certificate of
local infeasibility, local optimality or unboundedness of the (shifted)
feasible region. Our proposed algorithm differs from other IPM methods for
nonconvex programming because we reduce primal feasibility at the same rate as
the barrier parameter. This gives an algorithm with more robust convergence
properties and closely resembles successful algorithms from linear programming.
We implement the algorithm and compare with IPOPT on a subset of CUTEst
problems. Our algorithm requires a similar median number of iterations, but
fails on only 9% of the problems compared with 16% for IPOPT. Experiments on
infeasible variants of the CUTEst problems indicate superior performance for
detecting infeasibility.
The code for our implementation can be found at
https://github.com/ohinder/OnePhase .Comment: fixed typo in sign of dual multiplier in KKT syste
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