8,037 research outputs found
Baryonic Resonances from the Interactions of the Baryon Decuplet and Meson Octet
We study -wave interactions of the baryon decuplet with the octet of
pseudoscalar mesons using the lowest order chiral Lagrangian. We find two bound
states in the SU(3) limit corresponding to the octet and decuplet
representations. These are found to split into eight different trajectories in
the complex plane when the SU(3) symmetry is broken gradually. Finally, we are
able to provide a reasonable description for a good number of 4-star
resonances listed by the Particle Data Group. In particular, the
, the and the states are well
reproduced. We predict a few other resonances and also evaluate the couplings
of the observed resonances to the various channels from the residues at the
poles of the scattering matrix from where partial decay widths into different
channels can be evaluated.Comment: Contribution to the HADRON05 Conference, Rio de Janeiro, September
200
Radiative vector meson decay
We study the radiative , and decay into and taking into account mechanisms in which there
are two sequential vector-vector-pseudoscalar or
axial-vector--vector--pseudoscalar steps followed by the coupling of a vector
meson to the photon, considering the final state interaction of the two mesons.
Other mechanisms in which two kaons are produced through the same sequential
mechanisms or from vector meson decay into two kaons which undergo final state
interaction leading to the final pair of pions or , are also
considered. The results of the parameter free theory, together with the
theoretical uncertainties, are compared with the latest experimental results at
Frascati and Novosibirsk.Comment: Prepared for the 10th International Symposium on Meson-Nucleon
Physics and the Structure of the Nucleo
Numerical simulations of quiet Sun magnetic fields seeded by Biermann battery
The magnetic fields of the quiet Sun cover at any time more than 90\% of its
surface and their magnetic energy budget is crucial to explain the thermal
structure of the solar atmosphere. One of the possible origins of these fields
is due to the action of local dynamo in the upper convection zone of the Sun.
Existing simulations of the local solar dynamo require an initial seed field,
and sufficiently high spatial resolution, in order to achieve the amplification
of the seed field to the observed values in the quiet Sun. Here we report an
alternative model of seeding based on the action of the Bierman battery effect.
This effect generates a magnetic field due to the local imbalances in electron
pressure in the partially ionized solar plasma. We show that the battery effect
self-consistently creates from zero an initial seed field of a strength of the
order of micro G, and together with dynamo amplification, allows the generation
of quiet Sun magnetic fields of a similar strength to those from solar
observations.Comment: To appear in Astronomy & Astrophysic
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