BRAG
2007
1-day
pre-meeting before NSTAR 2007
Tuesday, September 4, 2007
University of Bonn, Germany
As for
the previous NSTAR workshops,
this year we have also organized a 1-day BRAG meeting in Bonn preceding the actual event.
This time the main topic is:
What kind of physical meaning can we attribute
to the
bare quantities
in
coupled-channel formalisms?
Everybody who is interested
in this subject
is invited to participate.
In order to organize an appropriate seminar
room and coffee,
please send us an email, if you are planning to participate.
Simon Capstick (BRAG chair)
Alfred Svarc
Lothar Tiator
preliminary list of speakers:
| Simon Capstick
(FSU) |
Un-quenching the quark
model |
| Jambul Gegelia (Mainz) |
On the definition of the D mass and width in EFT |
| Mauro Giannini (Genova) |
Longitudinal and
transverse helicity amplitudes of nucleon resonances
in a constituent quark model - bare vs dressed resonance couplings |
|
Christoph Hanhart (Jülich) |
What
we can learn from spectroscopy
--- and what not |
| Stefan Scherer (Mainz) |
From
the chiral to the physical limit, from
off-shell to on-shell kinematics |
|
Alfred Svarc (Zagreb) |
Bare
propagator poles in coupled-channel
models |
preliminary program:
location: Seminar Room I (room# 154),
Helmholtz-Institut für Strahlen- und Kernphysik (HISKP)
see map
all talks will be 20 min plus 10 min of discussion
short presentations (1-2 transparencies) are possible during the
general discussion sessions
morning session
chair: Lothar Tiator (Mainz)
10:00 Opening
10:10 Alfred Svarc
10:40 Simon Capstick
11:10 Christoph Hanhart
11:40 short presentations and general discussion (I)
12:30 - 14:00 Lunch break
afternoon session
chair: Alfred Svarc (Zagreb)
14:00 Stefan Scherer
14:30 Jambul Gegelia
15:00 Mauro Giannini
15:30 short presentations and general discussion (II)
17:00 NSTAR2007 Registration and Get Together
list of participants:
Beck, Reinhard, HISKP, Universität Bonn, Bonn, Germany
Bellis, Matt, Physics Department, Carnegie Mellon University, Pittsburgh, PA, USA
Briscoe, Bill, Physics Department, The George Washington University, Washington, DC, USA
Buchmann, Alfons, Universität Tübingen, Tübingen, Germany
Capstick, Simon, Florida State University, Tallahassee, FL, USA
Ceci, Sasa, Rudjer Boskovic Institute, Zagreb, Croatia
Djukanovic, Dalibor, Institut für Kernphysik, Universität Mainz, Mainz, Germany
Gegelia, Jambul, Institut für Kernphysik, Universität Mainz, Mainz, Germany
Giannini, Mauro, Dipartimento di Fisica, Universita di Genova, Genova, Italy
Hanhart, Christoph, Forschungszentrum Jülich, Jülich, Germany
Haidenbauer, Johann, Forschungszentrum Jülich, Jülich, Germany
Kamalov, Sabit, Laboratory of Theoretical Physics, JINR, Dubna, Russia
Metsch, Bernard, HISKP, Universität Bonn, Bonn, Germany
Saghai, Bijan, Nuclear Physics Department, CEA-Saclay, Paris, France
Scherer, Stefan, Institut für Kernphysik, Universität Mainz, Mainz, Germany
Shklyar, Vitaly, Institut für Theoretische Physik, Universität Giessen, Giessen, Germany
Svarc, Alfred, Rudjer Boskovic Institute, Zagreb, Croatia
Tiator, Lothar, Institut für Kernphysik, Universität Mainz, Mainz, Germany
Vancraeyveld, Pieter, Theoretical Medium-Energy Physics, Universiteit Gent, Gent, Belgium
Zhao, Qiang, Institute of High Energy Physics, Chinese Academy of Sciences and Department of
Physics, University of Surrey
goals of this meeting:
For decades coupled-channel models are extensively used in various
fields of physics, but a clear physical interpretation of bare quantities,
coming from the recurrent integral structure of the model, have not yet been
given. Present interpretations range from not giving them a direct physical
meaning [1,2], to hoping for a strong correlation between them and the hadron-structure
calculation functions (in most cases constituent quark models) [3,4].
The situation is far from being settled, because physicists close to
the field theory on the basis of field-theory first principles simply do
not see a fundamental way to link macroscopic coupled-channel functions to the microscopic
quark structure calculation ones, while phenomenologists do believe that
singling out the self-energy contributions arising from the interaction of some
bare entity with the meson cloud, should bring them closer to the fundamental
particle structure.
The main aim of this workshop is to remedy
this situation. We do not expect to come out with the final answer. We would
like to have all opinions formulated, expressed, and presented in a checkable
and reproducible form. Only when we see all arguments pro and contra
scientifically presented, may we expect that some of us may make a breakthrough
and clarify the problem.
Both sides have their standpoints and hopes; the question is if we
can find a way to conciliate them into a coherent picture.
The idea of this workshop is to be a workshop of cooperation, and
not a workshop of confrontation. We should start talking to each other.
incomplete list of references:
[1] P.J. Fink et al, Phys. Rev. C 41, 2720 (1990), see a comment given as ref.
21.
[2] C. Hanhart, A. Sibirtsev, private communication.
[3] A. Matsuyama, T. Sato and T. -S. H.
Lee, Phys. Rep. 439, 193 (2007)
and references therein starting in 1996 regarding Δ photoproduction;
B. Julia-Diaz, T.-S.H. Lee, A.
Matsuyama, and T. Sato, arXiv:0704.1615.
[4] G.-Y. Chen, S. Kamalov, S.N. Yang, D. Drechsel,
and L. Tiator, nucl-th/0703096;
L.
Tiator, D. Drechsel, S. Kamalov, M.M. Giannini, E. Santopinto, and A. Vassallo,
Eur. Phys. J. A 19, 55 (2004) and nucl-th/0310041.
contributions to this meeting (papers and talks):
