1,514 research outputs found
Dynamically Spontaneous Symmetry Breaking and Masses of Lightest Nonet Scalar Mesons as Composite Higgs Bosons
Based on the (approximate) chiral symmetry of QCD Lagrangian and the bound
state assumption of effective meson fields, a nonlinearly realized effective
chiral Lagrangian for meson fields is obtained from integrating out the quark
fields by using the new finite regularization method. As the new method
preserves the symmetry principles of the original theory and meanwhile keeps
the finite quadratic term given by a physically meaningful characteristic
energy scale , it then leads to a dynamically spontaneous symmetry
breaking in the effective chiral field theory. The gap equations are obtained
as the conditions of minimal effective potential in the effective theory. The
instanton effects are included via the induced interactions discovered by 't
Hooft and found to play an important role in obtaining the physical solutions
for the gap equations. The lightest nonet scalar mesons(, ,
and ) appearing as the chiral partners of the nonet pseudoscalar mesons
are found to be composite Higgs bosons with masses below the chiral symmetry
breaking scale GeV. In particular, the mass of the
singlet scalar (or the ) is found to be MeV.Comment: 15 pages, Revtex, published version, Eur. Phys. J. C (2004) (DOI)
10.1140/epjcd/s2004-01-001-
g-2 in composite models of leptons
Based on the bound state description of the muon and general relativistic
covariant quantum field theory, we illustrate with a simple composite model
that the observed deviation of (g-2)_\mu can be a demonstration of the
substructure of the muon and give the constraints on the radius of the muon in
different cases of light constituents and heavy constituents.Comment: 14 pages, 4 eps figures, revtex, several arguments and some
references renewe
Twist-3 contribution to the pion electromagnetic form factor
Non-leading contribution to the pion electromagnetic form factor which comes
from the pion twist-3 wave function is analyzed in the modified hard scattering
approach (MHSA) proposed by Li and Sterman. This contribution is enhanced
significantly due to bound state effect (the twist-3 wave function is
independent of the fractional momentum carried by the parton and has a large
factor with being the pion meson mass and
being the mean u- and d-quark masses). Consequently, although it is suppressed
by the factor , the twist-3 contribution is comparable with and even
larger than the leading twist (twist-2) contribution at intermediate energy
region of being .Comment: 10 pages, 2 fgures, latex. More discussions on the Sudakov effect
added, references added. To appear in European Physical Journal C
(Zeitschrift fur Physik C
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