123,606 research outputs found
Baryon Masses in the 1/N Expansion
The masses of baryons and heavy quark baryons are studied analytically in an
expansion in 1/N, SU(3) flavor symmetry breaking and heavy-quark symmetry
breaking. The measured baryon masses are in striking agreement with the 1/N
hierarchy.Comment: Lattice 2000 (Spectrum
Charm and Bottom Baryon Masses in the 1/N Expansion
The masses of heavy quark baryons are studied in an expansion in 1/N_c, SU(3)
flavor symmetry breaking, and heavy-quark symmetry breaking. Very accurate
model-independent mass relations are obtained for charm and bottom baryons.Comment: Proceedings of ICHEP2002, Amsterda
Hyperfine Mass Splittings of Baryons Containing a Heavy Quark in Large N QCD
The hyperfine mass splittings of baryons containing a heavy quark are derived
at leading order in large QCD. Hyperfine splittings either preserve or
violate heavy quark spin symmetry. Previous work proves that the splittings
which preserve heavy quark spin symmetry are proportional to at
order , where is the angular momentum of the light degrees of freedom
of the baryon. This work proves that the splittings which violate heavy quark
spin symmetry are proportional to at order in the and expansions.Comment: (8 pages, no figures, uses harvmac), UCSD/PTH 93-2
Baryon-Pion Couplings from Large-N QCD
We derive a set of consistency conditions for the pion-baryon coupling
constants in the large-N limit of QCD. The consistency conditions have a unique
solution which are precisely the values for the pion-baryon coupling constants
in the Skyrme model. We also prove that non-relativistic spin-flavor
symmetry (where is the number of light flavors) is a symmetry of the
baryon-pion couplings in the large-N limit of QCD. The symmetry breaking
corrections to the pion-baryon couplings vanish to first order in .
Consistency conditions for other couplings, such as the magnetic moments are
also derived.Comment: (12 pages, 2 figs, uses harvmac and uufiles), UCSD/PTH 93-1
Light Quark Spin-Flavor Symmetry for Baryons Containing a Heavy Quark in Large N QCD
The couplings and interactions of baryons containing a heavy quark are
related by light quark spin-flavor symmetry in the large limit. The single
pion coupling constant which determines all heavy quark baryon-pion couplings
is equal to the pion coupling constant for light quark baryons. Light quark
symmetry relations amongst the baryon couplings are violated at order .
Heavy quark spin-flavor symmetry is used in conjunction with large light
quark spin-flavor symmetry to determine the couplings of the degenerate
doublets of heavy quark baryons.Comment: (14 pages, 2 figs, uses harvmac and uufiles), UCSD/PTH 93-1
Large-N Baryons, Chiral Loops, and the Emergence of the Constituent Quark
Meson loop corrections to baryon axial currents are computed in the 1/N
expansion. It is already known that the one-loop corrections are suppressed by
a factor 1/N; here it is shown that the two-loop corrections are suppressed by
(1/N)^2. To leading order, these corrections are exactly what would be
calculated in the constituent quark model. Some applications are discussed
Naturalness of the Coleman-Glashow Mass Relation in the 1/N_c Expansion: an Update
A new measurement of the Xi^0 mass verifies the accuracy of the
Coleman-Glashow relation at the level predicted by the 1/N_c expansion. Values
for other baryon isospin mass splittings are updated, and continue to agree
with the 1/N_c hierarchy.Comment: 6 pages, revte
Semiclassical Meson-Baryon Dynamics from Large-Nc QCD
The large- limit of the meson-baryon effective Lagrangian is shown to
reduce to a semiclassical field theory. A chiral bag structure emerges
naturally in the limit. A possible connection between
the chiral bag picture and the Skyrme model is discussed. The classical
meson-baryon theory is used to reproduce the non-analytic correction
to the baryon mass obtained previously as a loop correction in chiral
perturbation theory.Comment: (13 pages, 1 figure, uses harvmac and uufiles), UCSD/PTH 94-1
Incidence of the WTO Anti-Discrimination Rules on Corporation Income Taxation
Many countries with free trade zones or export processing zones now exempt from corporate income taxation the income of firms exporting from these areas. The WTO has attempted to eliminate this exemption through its rules to promote the non-discrimination of fiscal systems with respect to export production. In particular, these rules do not allow countries to exempt the income of firms exporting from Free Trade Zones from corporate income taxation. This paper examines both theoretically as well as empirically the incidence of removing this corporate income tax exemption. The empirical analysis is carried out for the case of the Dominican Republic. The findings indicate that in the case of the Dominican Republic the removal of the corporate income tax exemption would inflict a burden on labour equal to about 6 times the amount of additional corporate tax revenue collected from the companies operating in its free trade zones.WTO, tax incidence, Free Trade Zones, corporate taxation
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