785 research outputs found
Predicative Ability of QCD Sum Rules for Decuplet Baryons
QCD sum rules for decuplet baryon two-point functions are investigated using
a comprehensive Monte-Carlo based procedure. In this procedure, all
uncertainties in the QCD input parameters are incorporated simultaneously,
resulting in realistic estimates of the uncertainties in the extracted
phenomenological parameters. Correlations between the QCD input parameters and
the phenomenological parameters are studied by way of scatter plots. The
predicted couplings are useful in evaluating matrix elements of decuplet
baryons in the QCD sum rule approach. They are also used to check a cubic
scaling law between baryon couplings and masses, as recently found by Dey and
coworkers. The results show a significant reduction in the scaling constant and
some possible deviations from the cubic law.Comment: 13 pages, RevTeX, 5 PS figures embedded with psfig.st
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Calculation of coupling constant g_phi-pi-gamma in QCD sum rules
The coupling constant of g_phi-pi-gamma decay is calculated in the method of
QCD sum rules. A comparison of our prediction on the coupling constant with the
result obtained from analysis of the experimental data is performed.Comment: 6 pages, 3 figure
Adaptive devices in young people with upper limb reduction deficiencies: Use and satisfaction
B0 - anti-B0 mixing beyond factorization
We present a calculation of the B0 - anti-B0 mixing matrix element in the
framework of QCD sum rules for three-point functions. We compute alpha_s
corrections to a three-point function at the three-loop level in QCD
perturbation theory, which allows one to extract the matrix element with
next-to-leading order (NLO) accuracy. This calculation is imperative for a
consistent evaluation of experimentally-measured mixing parameters since the
coefficient functions of the effective Hamiltonian for B0 - anti-B0 mixing are
known at NLO. We find that radiative corrections violate factorization at NLO;
this violation is under full control and amounts to 10%.Comment: 4 pages, 3 figures, LaTeX2
Unitarity Constraints on the B and B^* Form Factors from QCD Analyticity and Heavy Meson Spin Symmetry
A method of deriving bounds on the weak meson form factors, based on
perturbative QCD, analyticity and unitarity, is generalized in order to fully
exploit heavy quark spin symmetry in the ground state doublet of
pseudoscalar and vector mesons. All the relevant form factors of
these mesons are taken into account in the unitarity sum. They are treated as
independent functions along the timelike axis, being related by spin symmetry
only near the zero recoil point. Heavy quark vacuum polarisation up to three
loops in perturbative QCD and the experimental cross sections are used as input. We obtain bounds on the charge radius
of the elastic form factor of the meson, which considerably improve
previous results derived in the same framework.Comment: 13 pages LaTex, 1 figure as a separate ps fil
Gluonic Correlations in Matter
We derive the analogue of the QCD low energy theorems for the scalar and
pseudoscalar gluonic correlators in nuclear matter. We find that the scalar
correlations are depleted while the pseudoscalar correlations are enhanced to
leading order in the nuclear matter density. We briefly discuss the
consequences of these findings on the QCD spectrum.Comment: 9 pages, LaTe
Octet Baryons at Finite Temperature: QCD Sum Rules vs. Chiral Symmetry
Correlators of the octet baryons in the hot pion gas are studied in the
framework of the QCD sum rule. The condensates appearing in the OPE side of the
correlators become T-dependent through the interaction with thermal pions. We
present an explicit demonstration that the -dependence of the
condensates is completely compensated by the change of the pole residue and the
scattering effect in the spectral functions. Therefore
the baryon masses are constant to this order, although
, which
is consistent with the chiral symmetry constraint by Leutwyler and Smilga.Comment: 19 pages, MSUNSCL-870, LaTex files, 2 figs. consisting of simple
Feynmann diagrams not included, Phys.Rev.D in pres
Magnetic Moments of Decuplet Baryons in Light Cone QCD
We calculate the magnetic moments of decuplet baryons containing strange
quarks within the framework of light cone QCD sum rules taking into account the
SU(3) flavor symmetry breaking effects. It is obtained that magnetic moments of
the neutral \sso and \xis0 baryons are mainly determined by the SU(3)
breaking terms. A comparison of our results on the magnetic moments of the
decuplet baryons with the predictions of other approaches is presented.Comment: Latex, 20 pages, 6 figure
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