From hosaka@rcnp.osaka-u.ac.jp Thu May  2 18:22:54 2002
Date: Thu, 02 May 2002 10:28:24 +0900
From: Atsushi Hosaka <hosaka@rcnp.osaka-u.ac.jp>
To: ml-rcnp@rcnp.osaka-u.ac.jp, ml-rcnp-english@rcnp.osaka-u.ac.jp
Subject: seminar workshop today

Dear Colleagues,  

There is an RCNP seminar-workshop today
from 2pm at the lecture room on the fourth floor:

Speaker:  Miho Koma (Takayama)
Title:  Properties of excited baryons in a deformed oscillator quark
model.  
Abstract:
We study the masses and  transition properties of flavor SU(3)
excited baryons, paying a special attention to their spatial
deformation, as inspired by the similarity between the spectrum of
excited nucleons and that of deformed nuclei.  The deformed excited
states of baryons are practically described by the deformed oscillator
quark (DOQ) model, which is a constituent quark model with a deformed
harmonic oscillator potential.  A unique pattern of the rotational
bands formed by deformed states is obtained with only one scale
parameter, which is compared with all existing data of the flavor
SU(3) excited baryons systematically.  It is found that most of
well-established data (three- and four-star states in particle data
table) fall into the DOQ scheme.  This fact seems to suggest the
spatial deformation of excited baryons.

Furthermore, we study transition properties of
the excited baryons in terms of their spatially deformed wave
functions calculated within the DOQ model.
In this talk,  strong ``intra-band transitions''
between excited states
which belong to the same rotational band in the DOQ model are reported.
The transition amplitudes and decay widths
for the process, $N^{*} \to N^{*}\pi$, expected to be observed in
$N^{*} \to N\pi\pi$ in future,
are calculated, suggesting that some decay channels
have strong deformation dependence.

cheers, 
A. Hosaka