3,053 research outputs found
On the miracle of the Coleman-Glashow and other baryon mass formulas
Due to a new measurement of the Xi(0) mass,the Coleman-Glashow formula for
the baryon octet e.m. masses (derived using unbroken SU(3) is satisfied to an
extraordinary level of precision.The same unexpected precision exists for the
Gell-Mann Okubo formula and for its octet-decuplet extension
(G.Morpurgo,Phys.Rev.Lett. 68(1992)139).We show that the old question "why do
they work so well?" is now answered by the general parameterization method.Comment: 12 pages,Late
The baryon octet magnetic moments to all orders in flavor breaking; an application to the problem of the strangeness in the nucleon
Using the general QCD parametrization (GP) we display the magnetic moments of
the octet baryons including all flavor breaking terms to any order. The
hierarchy of the GP parameters allows to estimate a parameter related
to the quark loops contribution of the proton magnetic moment; its order of
magnitude is predicted to be inside a comparatively small interval including
the value given recently by Leinweber et al. by a lattice QCD calculationComment: (13 pages- version accepted for publication Phys.Rev.D. Note added in
last section, 2 references adde
Chiral QCD, General QCD Parameterization and Constituent Quark Models
Several recent papers -using effective QCD chiral Lagrangians- reproduced
results obtained with the general QCD parameterization (GP). These include the
baryon 8+10 mass formula, the octet magnetic moments and the coincidental
nature of the "perfect" -3/2 ratio between the magnetic moments of p and n.
Although we anticipated that the GP covers the case of chiral treatments, the
above results explicitly exemplify this fact. Also we show by the GP that -in
any model or theory (chiral or non chiral) reproducing the results of exact
QCD- the Franklin (Coleman Glashow) sum rule for the octet magnetic moments
must be violated.Comment: 10 pages, Latex; abridged version (same results), removed some
reference
Adams inequalities on measure spaces
In 1988 Adams obtained sharp Moser-Trudinger inequalities on bounded domains
of R^n. The main step was a sharp exponential integral inequality for
convolutions with the Riesz potential. In this paper we extend and improve
Adams' results to functions defined on arbitrary measure spaces with finite
measure. The Riesz fractional integral is replaced by general integral
operators, whose kernels satisfy suitable and explicit growth conditions, given
in terms of their distribution functions; natural conditions for sharpness are
also given. Most of the known results about Moser-Trudinger inequalities can be
easily adapted to our unified scheme. We give some new applications of our
theorems, including: sharp higher order Moser-Trudinger trace inequalities,
sharp Adams/Moser-Trudinger inequalities for general elliptic differential
operators (scalar and vector-valued), for sums of weighted potentials, and for
operators in the CR setting.Comment: To appear in Advances in Mathematics. 54 Pages, minor changes and
corrections in v2 (page 1, proof of Corollary 13, some typos). In v3 the more
relevant changes/corrections were made on pages 9, 10, 27, 32, 34, 36, 40,
41, 47. Minor corrections in v
A relation between the charge radii of \pi^{+},\K^{+},K^{o} derived by the general QCD parametrization
We derive,using the general QCD parametrization,the approximate relation
r^{2}(\pi^{+}) - r^{2}(K^(+)) approximately equal to -r^{2}(K^(o), where the
r's are the charge radii.The relation is satisfied but the experimental errors
are still sizeable.The derivation is similar to (but even simpler than) that
for r^{2}(p) -r^{2}(n) approximately equal to r^{2}({\Delta})[Phys.Lett.B
448,107 (1999)].Comment: latex,5 pages,no figures.To appear in Europhysics Letters [two typos
in Abstract corrected
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