Abstract

The study of meson photoproduction on the nucleon is a very important tool to complete the puzzle of baryon excited states. GRAAL aim is the measurement of cross sections and of beam asymmetries for all the photonuclear reactions accessible in the energy range from 600 MeV up to 1.5 GeV. In the following preliminary results of the Σ beam asymmetry for ω photoproduction on the free proton in Hydrogen and on the quasi-free nucleon in Deuterium are shown. GRAAL is the first experiment in which both the charged and the radiative decay of ω meson are studied. Since the beam asymmetry is independent of the decay mode, the comparison of the results from the two channel allows an important check on data consistency. Results on the free proton are in good agreement with theoretical prediction from Zhao model and confirm the presence of P₁₃(1720) state. The analysis performed for the radiative decay is applied to the process of ω photoproduction on the quasi free nucleon in Deuterium.

J. P. Bocquet, V. Bellini, L. Casano, A. D’Angelo, R. Di Salvo, A. Fantini, D. Franco, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, A. S. Ignatov, A. Lapik, A. Lleres, P. Levi Sandri, F. Mammoliti, G. Mandaglio, M. Manganaro, D. Moricciani, A. N. Mushkarenkov, V. G. Nedorezov, C. Randieri, D. Rebreyend, N. V. Rudnev, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge, V. Vegna (2010)

International Journal of Modern Physics E – June 2010, Vol. 19, Issues 5-6, pp. 1241-1248, ISSN: 0218-3013, doi: 10.1142/S0218301310015734.

World Scientific Publishing Company was established in 1981 with only 5 employees in a tiny office. Today, the company employs more than 200 staff at its headquarters in Singapore and 450 globally. It has offices in New Jersey, London, Geneva, Hong Kong, Taipei, Beijing, Shanghai, Tianjin and Chennai. In about 3 decades, it has established itself as one of the leading scientific publishers in the world, and the largest international scientific publisher in the Asia-Pacific region. World Scientific publishes about 600 new titles a year and 130 journals in various fields.

The International Journal of Modern Physics E covers the topics on experimental, theoretical and computational nuclear science, and its applications and interface with astrophysics and particle physics. The journal includes both review articles and research papers.