190 research outputs found
Baryonium, a common ground for atomic and high energy physics
Indications of the existence of quasi-bound states in the N-Nbar system are
presented. Measurements by BES discovered a broad enhancement close to the
p-pbar threshold in the S wave, isospin 0 state formed in radiative decays of
J/psi. Another enhancement located about 50 MeV below the threshold was found
in mesonic decays of J/psi. In terms of the Paris potential model it was shown
that these are likely to represent the same state. Antiprotonic atomic data
provide some support for this interpretation and indicate the existence of
another fairly narrow quasi-bound state in a P wave.Comment: 6 pages, 6 figures - Contribution to EXA2014 Vienna to appear in a
special edition of Hyperfine Interaction
K* resonance effects on direct CP violation in B -> pi pi K
Charged and neutral B decays into two charged pions and a charged or a
neutral kaon are analyzed within the QCD factorization scheme where final state
interactions before and after hadronization are included. The K*(892) and
K*(1430) resonance effects are taken into account using the presently known
pion-Kaon strange vector and scalar form factors. The weak decay amplitudes,
which are calculated at leading power in Lambda_QCD/m_b and at the
next-to-leading order in the strong coupling constant, include the hard
scattering and annihilation contributions. The end point divergences of these
weak final state interactions are controlled by two complex parameters
determined through a fit to the available effective mass and helicity angle
distribution, CP asymmetry and K*(892) branching ratio data. The predicted
K*(1430) branching ratios and the calculated direct CP violation asymmetries
are compared to the Belle and BABAR Collaboration data.Comment: Comments: 22 pages, 2 figures and 3 tables. In this new version, the
results are unchanged, but, the last paragraph of the Section "RESULTS AND
SUMMARY" (now called "RESULTS AND DISCUSSION") has been replaced by a new
Section "SUMMARY AND OUTLOOK". To appear in Physical Review
On the structure of the X(1835) baryonium
The measurement by the BES collaboration of J/psi -> gamma p pbar decays
indicates an enhancement at the p-pbar threshold. In another experiment BES
finds a peak in the invariant mass of pi-mesons produced in the possibly
related decay J/psi -> gamma pi+ pi- eta'. Using a semi-phenomenological
potential model which describes all the N-Nbar scattering data, we show that
the explanation of both effects may be given by a broad quasi-bound state in
the spin and isospin singlet S wave. The structure of the observed peak is due
to an interference of this quasi-bound state with a background amplitude and
depends on the annihilation mechanism.Comment: 7 pages, 7 figures, this version corresponds to the published paper
in Phys. Rev. C: minor corrections done and in section 5 suggestions of
experiments to confirm the link of the X(1835) to the antiproton-proton
syste
Pseudoscalar-scalar transition form factors in covariant light front dynamics
In an explicitly covariant light-front formalism, we analyze transition form
factors between pseudoscalar and scalar mesons. Application is performed in
case of the transition in the full available transfer momentum
range .Comment: 4 pages, 4 figures. Talk given at the XXXIII International Conference
on High Energy Physics, ICHEP06, Moscow, 26 July-02 Augus
On the relationship of the scaled phase space and Skyrme-coherent state treatments of proton antiproton annihilation at rest
We discuss pion multiplicities and single pion momentum spectra from proton
antiproton annihilation at rest. Both the scaled phase space model and the
Skyrme-coherent state approach describe these observables well. In the coherent
state approach the puzzling size of the scale parameter relating the phase
space integrals for different multiplicities is replaced by a well defined
weight function. The strength of this function is determined by the intensity
of the classical pion field and its spatial extent is of order 1 fm.Comment: 11 pages including 4 figures(postscript
SUSY Quantum Mechanics with Complex Superpotentials and Real Energy Spectra
We extend the standard intertwining relations used in Supersymmetrical (SUSY)
Quantum Mechanics which involve real superpotentials to complex
superpotentials. This allows to deal with a large class of non-hermitean
Hamiltonians and to study in general the isospectrality between complex
potentials. In very specific cases we can construct in a natural way
"quasi-complex" potentials which we define as complex potentials having a
global property such as to lead to a Hamiltonian with real spectrum. We also
obtained a class of complex transparent potentials whose Hamiltonian can be
intertwined to a free Hamiltonian. We provide a variety of examples both for
the radial problem (half axis) and for the standard one-dimensional problem
(the whole axis), including remarks concerning scattering problems.Comment: 22 pages, Late
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