K. P. Khemchandani, A. Martínez Torres, H. Kaneko, H. Nagahiro, A. Hosaka
In this manuscript, I will report the details of our recent work on the
vector meson-baryon (VB) interaction, which we studied with the motivation of
finding dynamical generation of resonances in the corresponding systems. We
started our study by building a formalism based on the hidden local symmetry
and calculating the leading order contributions to the scattering equations by
summing the diagrams with: (a) a vector meson exchange in the t-channel (b) an
octet baryon exchange in the s-, u-channels and (c) a contact interaction
arising from the part of the vector meson-baryon Lagrangian which is related to
the anomalous magnetic moment of the baryons. We find the contribution from all
these sources, except the s-channel, to be important. The amplitudes obtained
by solving the coupled channel Bethe-Salpeter equations for the systems with
total strangeness zero, show generation of one isospin 3/2, spin 1/2 resonance
and three isospin 1/2 resonances: two with spin 3/2 and one with spin 1/2. We
identify these resonances with $\Delta$ (1900) $S_{31}$, $N^*$(2080) $D_{13}$,
$N^*$(1700) $D_{13}$, and $N^*$(2090) $S_{11}$, respectively.
We have further extended our study by including pseudoscalar meson-baryon
(PB) as the coupled channels of VB systems. For this, we obtain the PB
$\rightarrow$ VB amplitudes by 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 low-lying resonances like $\Lambda$(1405)
and $\Lambda$(1670), which can have important implications on certain reactions
producing them. In addition to this, we find that the effect of coupling the
higher mass states to the lighter channels is not restricted to increasing the
width of those states, it can be far more strong.
View original:
http://arxiv.org/abs/1202.3840
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