589 research outputs found
Dynamical masses of quarks in quantum chromodynamics
Using Dyson-Schwinger equations we obtain an ultraviolet asymptotics for the
dynamical mass of quark in QCD. We also determine a numerical value for the \pi
meson decay constant f_\pi.Comment: Electronic version of the published paper, latex, 4 page
Momentum dependent quark mass in two-point correlators
A momentum dependent quark mass may be incorporated into a quark model in a
manner consistent with dynamically broken chiral symmetry. We use this to study
the high behavior of the vector, axialvector, scalar and pseudoscalar
two-point correlation functions. Expanding the results to order , we
show the correspondence between the dynamical quark mass and the vacuum
condensates which appear in the operator product expansion of QCD. We recover
the correct leading logarithmic dependence of the various terms in the
OPE, but we also find substantial subleading corrections which are numerically
huge in a specific case. We conclude by using the vector minus axialvector
correlator to estimate the electromagnetic mass difference.Comment: 18 pages, LaTeX, figures in accompanying uuencoded postscript file.
Published version. References adde
Vertices and the CJT Effective Potential
The Cornwall-Jackiw-Tomboulis effective potential is modified to include a
functional dependence on the fermion-gauge particle vertex, and applied to a
quark confining model of chiral symmetry breaking.Comment: 10 pages (latex), PURD-TH-93-1
Implementing Collective Bargaining Enabling Legislation : Washington Universities Join the Party
In 2002, Washington passed enabling legislation that, for the first time, expressly granted
to the faculty at the state’s public four-year colleges and universities the right to bargain
regarding their terms and conditions of employment. To date, faculty at four of the state’s
six four-year public institutions of higher education have formed unions, and two of those
unions have negotiated first contracts. This paper describes the history of that process,
the legal framework in which it took place, and the issues of greatest importance at the
bargaining table
Calculation of the Chiral Lagrangian Coefficients from the Underlying Theory of QCD: A Simple Approach
We calculate the coefficients in the chiral Lagrangian approximately from QCD
based on a previous study of deriving the chiral Lagrangian from the first
principles of QCD in which the chiral Lagrangian coefficients are defined in
terms of certain Green's functions in QCD. We first show that, in the large
N(c)-limit, the anomaly part contributions to the coefficients are exactly
cancelled by certain terms in the normal part contributions, and the final
results of the coefficients only concern the remaining normal part
contributions depending on QCD interactions. We then do the calculation in a
simple approach with the approximations of taking the large-N(c) limit, the
leading order in dynamical perturbation theory, and the improved ladder
approximation, thereby the relevant Green's functions are expressed in terms of
the quark self energy. By solving the Schwinger-Dyson equation for the quark
self energy, we obtain the approximate QCD predicted coefficients and the quark
condensate which are consistent with the experimental values.Comment: Further typos corrected, to appear in Phys. Rev.
Large Possible retardation effects of quark confinement on the meson spectrum II
We present the results of a study of heavy-light-quark bound states in the
context of the reduced Bethe-Salpeter equation with relativistic vector and
scalar interactions. We find that satisfactory fits may also be obtained when
the retarded effect of the quark-antiquark interaction is concerned.Comment: 11 pages, RevTex, to appear in PR
Constraints from on gauge-mediated supersymmetry breaking models
We consider the branching ratio of in gauge mediated
supersymmetry breaking theories. Useful bounds on the parameter space of these
models are derived from the experimental bounds on . Constraints
on masses of NLSP are presented as a function of and for
.Comment: 12 pages(Latex), 3 PS Figures (uuencoded, epsf.tex); minor
modification in the introductory part of the tex
Possible retardation effects of quark confinement on the meson spectrum
The reduced Bethe-Salpeter equation with scalar confinement and vector gluon
exchange is applied to quark-antiquark bound states. The so called intrinsic
flaw of Salpeter equation with static scalar confinement is investigated. The
notorious problem of narrow level spacings is found to be remedied by taking
into consideration the retardation effect of scalar confinement. Good fit for
the mass spectrum of both heavy and light quarkomium states is then obtained.Comment: 14 pages in LaTex for
Chiral Dynamics and Heavy Quark Symmetry in a Toy Field Theoretic Model
We study a solvable QCD--like toy theory, a generalization of the
Nambu--Jona-Lasinio model, which implements chiral symmetries of light quarks
and heavy quark symmetry. The chiral symmetric and chiral broken phases can be
dynamically tuned. This implies a parity doubled heavy--light meson system,
corresponding to a multiplet and a heavy spin
multiplet. Consequently the mass difference of the two multiplets is given by a
Goldberger--Treiman relation and is found to be small. The Isgur--Wise
function, , the decay constant, , and other observables are
studied.Comment: 42 pages, SSCL-PP-243; Fermi-Pub-93/059-
Negative T from a dynamical left-handed neutrino mass
We show how a dynamical Majorana mass for a fourth family left-handed
neutrino can make a significant negative contribution to the electroweak
correction parameter T without making a large contribution to S or U. We also
comment on other possible contributions to T in the context of dynamical
symmetry breaking.Comment: 8 pages, postscript, version to be published as Rapid Communications
in PRD, PDF file is available at
http://miteymac.physics.utoronto.ca/bh/papers/papers.htm
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