16,479 research outputs found
Properties of nucleon in nuclear matter: once more
We calculate the mass and residue of the nucleon in nuclear matter in the
framework of QCD sum rules using the nucleon's interpolating current with an
arbitrary mixing parameter. We evaluate the effects of the nuclear medium on
these quantities and compare the obtained results with the existing theoretical
predictions. The results are also compared with those obtained in vacuum to
find the shifts in the quantities under consideration. Our calculations show
that these shifts in the mass and residue are about and ,
respectively.Comment: 18 Pages, 2 Tables and 7 Figures, To be appear in EPJ
Exclusive diffractive resonance production in proton-proton collisions at high energies
A model for exclusive diffractive resonance production in proton-proton
collisions at high energies is presented. This model is able to predict double
differential distributions with respect to the mass and the transverse momentum
of the produced resonance in the mass region 5 GeV. The model is
based on convoluting the Pomeron distribution in the proton with the
Pomeron-Pomeron-meson total cross section. The Pomeron-Pomeron-meson cross
section is saturated by direct-channel contributions from the Pomeron as well
as from two different trajectories, accompanied by the isolated f
resonance dominating the GeV region. A slowly varying
background is taken into account.Comment: 11 pages, 14 figures. arXiv admin note: text overlap with
arXiv:1512.0497
Predictions on , and from QCD Light-Cone Sum Rules
The form factors of the , and transitions
are calculated from QCD light-cone sum rules (LCSR) and used to predict the
widths and differential distributions of the exclusive semileptonic decays
, and ,
where . The current theoretical uncertainties are estimated. The LCSR
results are found to agree with the results of lattice QCD calculations and
with experimental data on exclusive semileptonic D decays. Comparison of the
LCSR prediction on with the CLEO measurement yields a
value of |V_{ub}| in agreement with other determinations.Comment: 24 pages, 12 figures, Latex, epsfig, some additional remarks on the
two-pole parameterization, prediction on the form factor added,
version to appear in Phys. Rev.
Indications of the possible observation of the lowest-lying 1^{-+} QCD state
We discuss properties of 1^{-+} exotic mesons within the framework of the QCD
field-theoretic approach. We estimate the mass of the lowest-lying 1^{-+}
exotic meson using renormalization-improved QCD sum rules, and find that the
mass lies around GeV, in good agreement with the
data. This state should be expected in QCD. We find that the mass for the
lowest-lying strange 1^{-+} meson is GeV. Our result hints that
the K^*(1410) may be the lowest-lying 1^{-+} nonet state.Comment: 6 pages, 3 figures; some typos corrected, Published versio
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