Preface
Resonances remain an important tool to study the structure and dynamics of hadrons and an efficient catalyst for our traditional Mini-Workshops at Bled. The many ideas, questions and responses presented at our meeting should not fade away and we thank the participants for submitting their contributions to the Proceedings as a permanent reminder of our common interests and discussions. An important aspect of the talks was the bridge between the phenomenological phase shift analyses and the theoretical interpretation of resonances. Attempts were shown to relate experimental data to pole parameters in a model-independent way, introducing additional constraints to obtain a unique solution. This year, the emphasis was on meson photoproduction, in particular of n and n', as well as doubly-polarized pion electroproduction. Of interest was also pion photoproduction on bound neutrons and the forward neutron asymmetry in proton-nucleus collisions.
The Roper resonance is still a challenge. It is not clear to which extent it is predominantly a three-quark system or a dynamically generated resonance. The dynamics of other baryons also requires an extension beyond the valence quark configurations. The knowledge of the baryon form-factors has improved both due to new experimental analyses as well due to new theoretical perspectives, especially regarding transition form-factors.
It was interesting to learn about the cluster separability in relativistic few body problems, about phase rotation ambiguities, and about the progress in understanding strength functions in hadronic and nuclear dynamics. The third emphasis was on new resonances in the charm sector. The meson and baryon resonances discovered at the Belle detector at KEKB are still being analysed in order to determine their quantum numbers and their double-qq or "molecular" dimeson structure. In view of the forthcoming Belle2 upgrade it is time to analyse the prospects of identifying the double charm baryons and the DD* dimesons (tetraquarks).
We were very happy to host such enthusiastic participants. We do hope to meet you at Bled again soon and that you will enjoy reading these Proceedings and refresh your memories of the subjects of our common interest. Perhaps you might wish to offer these Proceedings to your colleagues as a temptation to join us at Bled in the near future.
Ljubljana, November 2017	B. Golli, M. Rosina, S. Sirca
The full color version of the Proceedings are available at http://www-f1.ijs.si/BledPub, and the presentations can be found at http://www-f1.ijs.si/Bled2 017/Program.html.
Predgovor
Resonance so se vedno pomembno orodje za študijzgradbe in dinamike hadro-nov, pa tudi učinkovit katalizator za naše tradicionalne Blejske delavnice. Mnoge zamisli, vprasanja in odzivi, ki smo jih predstavili na nasem srečanju, ne smejo oveneti, zato se zahvaljujemo udelezencem, da so poslali svoje prispevke kot trajen spomin na nasa skupna zanimanja in razprave.
Pomemben vidik predavanjje bil most med fenomenolosko analizo faznih premikov in teoreticnim tolmacenjen resonanc. Predstavljeni so bili poskusi, kako povezati eksperimentalne podatke s parametri polov na modelsko neodvisen nacin, s tem da se vpeljejo dodatni pogoji, ki vodijo do enolicne resitve. Letos je bil poudarek na fotoprodukciji mezonov, zlasti n in n', pa tudi na elektropro-dukciji dvojno polariziranih pionov. Zanimiva je bila tudi fotoprodukcija pionov na vezanih nevtronih ter asimetrija nevtronov, ki letijo naprej pri trkih protonov na jedrih.
Roperjeva resonanca predstavlja se vedno izziv. Ni se jasno, do katere mere je pretezno sistem treh kvarkov ali dinamicno povzrocena resonanca. Dinamika mnogih drugih barionov tudi zahteva razsiritev modelov na konfiguracije, ki presegajo zgoljvalencne kvarke. Poznavanje barionskih oblikovnih faktorjev se je izpopolnilo zaradi novih eksperimentalnih analiz kakor tudi zaradi novih teo-reticnih pogledov, zlasti v zvezi z oblikovnimi faktorji za prehode.
Zanimiv je bil vpogled v locljivost gruc pri relativisticnem problemu malo teles, v mnogolicnost rotacije faz, pa tudi napredek pri razumevanju jakostnih funkcij v hadronski in jedrski dinamiki.
Tretji poudarek je bil na novih resonancah v carobnem sektorju. Mezonske in bar-ionske resonance, ki so jih odkrili na detektorju Belle na pospesevalniku KEKB, se vedno analizirajo, da bi dolocili njihova kvantna stevila in njihovo "molekularno" dimezonsko zgradbo v zvezi z dvojnimi pari qq. V perspektivi skorajšnjega pove-canja detektorja Belle2 je cas, da prevetrimo moznosti identifikacije dvojno carob-nih barionov ter dimezonov (tetrakvarkov) DD*.
Čutimo se srecne, da smo se druzili s tako navdusenimi udeleženci. Upamo, da vas bomo spet kmalu videli na Bledu in da boste uzivali branje tega Zbornika in osvezili spomine na probleme nasega skupnega zanimanja. Morda boste ponudili ta Zbornik svojim kolegom kot vabo, da se nam v bližnji prihodnosti pridružijo na Bledu.
Ljubljana, november 2017	B. Golli, M. Rosina, S. Sirca
Barvno verzijo lahko dobite na http://www-f1.ijs.si/BledPub in prosoj-nice predavanjna http://www-f1.ijs.si/Bled2017/Program.html.