18 research outputs found
A Non-Principal Value Prescription for the Temporal Gauge
A non-principal value prescription is used to define the spurious
singularities of Yang-Mills theory in the temporal gauge. Typical one-loop
dimensionally-regularized temporal-gauge integrals in the prescription are
explicitly calculated, and a regularization for the spurious gauge divergences
is introduced. The divergent part of the one-loop self-energy is shown to be
local and has the same form as that in the spatial axial gauge with the
principal-value prescription. The renormalization of the theory is also briefly
mentioned.Comment: 13 pages, NCKU-HEP/93-0
The Extended Nambu--Jona-Lasinio Model in Differential Regularization
We employ the method of differential regularization to calculate explicitly
the one-loop effective action of a bosonized extended
Nambu--Jona-Lasinio model consisting of scalar, pseudoscalar, vector and axial
vector fields.Comment: LaTeX, 17 page
Baryon wave function in large-Nc QCD: Universality, nonlinear evolution equation and asymptotic limit
The 1/Nc expansion is formulated for the baryon wave function in terms of a
specially constructed generating functional. The leading order of this 1/Nc
expansion is universal for all low-lying baryons [including the O(1/Nc) and
O(Nc^0) excited resonances] and for baryon-meson scattering states. A nonlinear
evolution equation of Hamilton-Jacobi type is derived for the generating
functional describing the baryon distribution amplitude in the large-Nc limit.
In the asymptotic regime this nonlinear equation is solved analytically. The
anomalous dimensions of the leading-twist baryon operators diagonalizing the
evolution are computed analytically up to the next-to-leading order of the 1/Nc
expansion.Comment: 44 page
Baryon Distribution Amplitudes in QCD
We develop a new theoretical framework for the description of leading twist
light-cone baryon distribution amplitudes which is based on integrability of
the helicity evolution equation to leading logarithmic accuracy.
A physical interpretation is that one can identify a new `hidden' quantum
number which distinguishes components in the distribution
amplitudes with different scale dependence. The solution of the corresponding
evolution equation is reduced to a simple three-term recurrence relation. The
exact analytic solution is found for the component with the lowest anomalous
dimension for all moments , and the WKB-type expansion is constructed for
other levels, which becomes asymptotically exact at large . Evolution
equations for the distribution amplitudes (e.g. for the nucleon)
are studied as well. We find that the two lowest anomalous dimensions for the
operators (one for each parity) are separated from the rest of
the spectrum by a finite `mass gap'. These special states can be interpreted as
scalar diquarks.Comment: 75 pages, LaTeX style, 18 figures embedded with epsf.st