28,675 research outputs found
Coupling vector and pseudoscalar mesons to study baryon resonances
A study of meson-baryon systems with total strangeness -1 is made within a
framework based on the chiral and hidden local symmetries. These systems
consist of octet baryons, pseudoscalar and vector mesons. The pseudoscalar
meson-baryon (PB) dynamics has been earlier found determinant for the existence
of some strangeness -1 resonances, for example, ,
, etc. The motivation of the present work is to study the effect
of coupling the closed vector meson-baryon (VB) channels to these resonances.
To do this, we obtain the and
amplitudes from the t-channel diagrams and the
amplitudes are calculated using the Kroll-Ruddermann term where, considering
the vector meson dominance phenomena, the photon is replaced by a vector meson.
The calculations done within this formalism reveal a very strong coupling of
the VB channels to the and . In the isospin 1
case, we find an evidence for a double pole structure of the
which, like the isospin 0 resonances, is also found to couple strongly to the
VB channels. The strong coupling of these low-lying resonances to the VB
channels can have important implications on certain reactions producing them.Comment: Minor typos corrected (in Eq.(22) and axis-labels of some figures
Plausible explanation of the puzzle
From a Faddeev calculation for the
system we show the plausible existence of three dynamically generated
baryon states below 2.3 GeV whereas only two
resonances, and
are cataloged in the Particle Data Book
Review. Our results give theoretical support to data analyses extracting two
distinctive resonances, and
from which the mass of
is estimated. We propose that these two
resonances should be cataloged instead of This
proposal gets further support from the possible assignment of the other baryon
states found in the approach in the with
sectors to known baryonic resonances. In
particular, is naturally interpreted as a bound state.Comment: 13 pages, 7 figure
Solution to Faddeev equations with two-body experimental amplitudes as input and application to J^P=1/2^+, S=0 baryon resonances
We solve the Faddeev equations for the two meson-one baryon system
and coupled channels using the experimental two-body -matrices for the interaction as input and unitary chiral dynamics to describe the interaction
between the rest of coupled channels. In addition to the obtained
before with the channel, we obtain, for and total
isospin of the three-body system , a resonance peak whose mass is around
2080 MeV and width of 54 MeV, while for we find a peak around 2126 MeV
and 42 MeV of width. These two resonances can be identified with the and the , respectively. We obtain another peak in the
isospin 1/2 configuration, around 1920 MeV which can be interpreted as a
resonance in the and systems.Comment: published versio
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