organizers e-mail address phone/fax number

Volker Burkert        JLab   burkert@cebaf.gov
                             ++1 757 269-7540/5800
Nimai C. Mukhopadhyay RPI    nimai@nimai.phys.rpi.edu 
                             ++1 518 276-6663/80
Bijan Saghai          Saclay saghai@phnx7.saclay.cea.fr
                             ++33 1 69087561/84
Silvano Simula        INFN   simula@hpteo2.iss.infn.it 
                             ++39 6 4941086/4462872

Quantum Chromodynamics (QCD) is widely recognized as the theory of the strong interaction. As is well known, perturbative QCD has allowed to reach an impressive understanding of inclusive processes involving hadrons. At the same time the non-perturbative aspects of the QCD description of exclusive processes still await for a deeper understanding.

It is well recognized that the investigation of processes involving the production of excited states of the nucleon (N*) can provide relevant information on the non-perturbative regime of QCD. In the next years, the issue of N* physics will be addressed by planned experiments at the Thomas Jefferson National Accelerator Facility (TJNAF), which will provide new experimental data in the so-called resonance region with an unprecedented accuracy. Both photo- and electro-production of single and double pions, eta and K mesons as well as vector mesons, will be measured at TJNAF in a wide range of kinematical conditions, thanks to the highly sophisticated CLAS detector. Spin observables will be also measured.

It is therefore clear that the interpretation of the huge amount of forthcoming data will require strong efforts and close collaborations between experimentalists and theoreticians. In this respect important developments in the experimental and theoretical investigation of the N* physics now occur. As for the theoretical side, progress have been made in developing reaction models and methods for analysing both the available and the expected data. At the same time, the predictions of several models of the hadron structure, like the constituent quark model, chiral and soliton models, as well as the predictions from QCD sum rule and lattice QCD approaches, have been refined. On the experimental side, it is expected that in the first half of 1998 new data will be available both from TJNAF and other facilities in the world, like MAMI$at Mainz, ELSA at Bonn and light sources at LEGS (Brookhaven National Laboratory) and GRAAL (Grenoble).

A series of workshops, specifically designed to facilitate the interactions among experimentalists and theoreticians, was held in the past few years, starting at the Florida State University in 1994 and continuing at CEBAF in 1995 and at the Institute for Nuclear Theory in Seattle in 1996 and the George Washington University in 1997. Along this line, a joint workshop between the European Center for Theoretical Studies in Nuclear Physics and Related Areas (ECT*) and the TJNAF laboratory, will be held at the ECT* from May 18 to May 29, 1998. Close to the proposed date, new experimental data are expected to emerge and the workshop will allow discussions of these data and suggestions for the new directions of the experimental and theoretical investigation of the N* physics.

The format of the Workshop is based on topical lectures (generally, two in the mornings and one in the afternoons) and informal discussion meetings, including short presentations in the afternoons, with a discussion leader.

Monday 18: 1. Highlights of N* physics with electron
              accelerators (CEBAF, ELSA, LEGS, GRAAL,
              MAMI): V. Burkert (CEBAF)
           2. Constituent quark models : N. Isgur (*)
              (JLab)
           3. Perturbative $QCD$ : S. Brodsky (*) (SLAC)

Tuesday 19: 1. N* physics at hadron machines :  
               K.  Killian (COSY)
            2. Collective algebraic models :  
               F.  Iachello (Yale)
            3. Boson exchange models of the quark 
               interaction :  D.O. Riska (Helsinki)

Wednesday 20 : 1. Amplitude analysis : R. Workman (VPI)
               2. Coupled channel analysis : D. Manley
                  (Kent)
               3. Polarization observables : F. Tabakin
                  (Pittsburgh)

Thursday 21 : 1. Single pion production (exp.) : 
                 A. Sandorfi (Brookhaven)
              2. Single pion production (theory) :
                 Harry Lee (Argonne)
              3. Nucleon and N-Delta form factors :
                 Ulf-G. Meissner (*) (Bonn)
              4. Nucleon axial form factors : 
                 B. Holstein (Massachussetts)

Friday 22 : 1. Real and virtual Compton scattering 
               (exp.): N. D'Hose (Saclay)
            2. Real and virtual Compton scattering 
               (theory): S. Scherer (Mainz)
            3. Missing resonances : S. Capstick (*)(FSU)

Saturday 23 : 1. Double pion production (exp.) :
                 B. Schoch (Bonn)
              2. Double pion production (theory) :
                 E. Oset (Valencia)


Monday 25 : 1. The Drell-Hearn-Gerasimov sum rule (exp.): 
               G. Anton (Erlangen)
            2. Dispersion approach to pion production
               and the DHG sum rule (theory) : 
               D. Drechsel (Mainz)
            3. Baryon form factors in the quark model :
               S. Simula (Roma)

Tuesday 26 : 1. Spin-dependent nucleon structure 
                functions: Z. Meziani
             2. Nucleon structure functions in the 
                quark model: M. Traini (Trento)
             3. Diquark models : P. Kroll (Wuppertal)

Wednesday 27 : 1. eta meson production (exp.) : 
                  J.P. Didelez (Orsay)
               2. eta and eta ' production (theory) :
                  N. Mukhopadhyay (RPI)
               3. Hybrids and exotics : F. Close (*)
                  (Rutherford)
               4. Lattice QCD calculations : K.-F. Liu
                  (Kentucky)

Thursday 28 : 1. K meson production (exp.) : 
                 R. Schumacher (CMU)
              2. K meson production (theory):
                 B. Saghai (Saclay)
              3. Unified quark-model for pseudoscalar 
                 mesons production : Zhenping Li 
                 (Beijing)

Friday 29 : 1. Vector meson production (exp.) :
               M. Ripani (Genova)
            2. Vector meson production (theory) :
               A. Donnachie (Manchester)
            3. QCD sum rules : A. Radyushkin (JLab)
            4. Summaries and perspectives.

The allotted time for each lecture is about one hour.

At any time the number of participants is limited to 35-40 and, therefore, the partecipation to the workshop is BY INVITATION only. The participants are encouraged to stay for the whole period of the workshop. Students and younger researchers are requested to add a recommendation by their adviser.

ECT* expects that participants cover their travel expenses and, possibly, also (part of) the local living expenses. In case you need financial support, please indicate so in the enclosed application form.

The second circular will include detailed information about housing, submission of contributions, proceedings, etc.

Name (title, last, first):

Institution:

Address:

Phone:

Fax:

E-mail:


_______ I am planning to attend the Workshop

_______ I am planning to attend the Workshop and submit a contribution tentative title:

expected duration of stay: accompanied by: type of accommodation needed (double/single room, .....):

requested financial support:


_______ I am not sure if I will attend the workshop but I would like to receive future communications


Additional remarks:

Silvano Simula Istituto Nazionale di Fisica Nucleare Sezione Sanita' Viale Regina Elena 299 I-00161 Roma (Italy)

FAX: ++39 - 6 - 4462872

E-MAIL: simula@hpteo2.iss.infn.it


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last updated May 15, 1998