https://doi.org/10.1051/epjconf/20100307017
Baryon resonances in the baryon meson scattering coupled to the q3-state
1
Japan College of Social Work, Kiyose, Tokyo
204-8555,
Japan
2
Department of Physics, Sophia University, Kioi,
Chiyoda,
Tokyo
102-8554,
Japan
a e-mail: s.takeuchi@jcsw.ac.jp
We investigate Λ(1405), ∆(1232), and
N* (1440) as resonances in the baryon-meson scattering with bound
states embedded in the continuum (BSEC). This BSEC is introduced by hand, as a
state not originated from a simple baryon-meson system. We assume it comes from
the three-quark state. The resonances are successfully reproduced by this
scheme. As for the Λ(1405) resonance, it is found that our
calculation can give an appropriate energy and width for the peak and reproduces
the scattering length when the BSEC contribution to the resonance is roughly
half of that of the
channel. The energy of the three-quark pole for
∆(1232) is taken to be 1327 MeV, which comes down to 1232
MeV after the mixing to the Nπ and ∆π
scattering states is included. The nucleon also gets the self energy of about
130 MeV, so the N∆ mass difference, which is one of the key
values in the quark model, does not change much. It also found that the positive
parity excited nucleon mass can be reduced by more than 400 MeV and become
around 1440 MeV after the mixing to the continuum is taken into account.
© Owned by the authors, published by EDP Sciences, 2010