1204.2914 (M. Nanova et al.)

Transparency ratio in γA -> η' A' and the in-medium η' width    [PDF]

M. Nanova, V. Metag, A. Ramos, E. Oset, I. Jaegle, K. Makonyi, K. Brinkmann, O. Bartholomy, D. Bayadilov, Y. A. Beloglazov, V. Crede, H. Dutz, A. Ehmanns, D. Elsner, K. Essig, R. Ewald, I. Fabry, M. Fuchs, Ch. Funke, R. Gregor, A. B. Gridnev, E. Gutz, S. Höffgen, P. Hoffmeister, I. Horn, J. Junkersfeld, H. Kalinowsky, Frank Klein, Friedrich Klein, E. Klempt, M. Konrad, B. Kopf, B. Krusche, J. Langheinrich, H. Löhner, I. V. Lopatin, J. Lotz, S. Lugert, D. Menze, T. Mertens, J. G. Messchendorp, C. Morales, R. Novotny, M. Ostrick, L. M. Pant, H. van Pee, M. Pfeiffer, A. Roy, A. Radkov, S. Schadmand, Ch. Schmidt, H. Schmieden, B. Schoch, A. Süle, V. V. Sumachev, T. Szczepanek, U. Thoma, D. Trnka, R. Varma, D. Walther, Ch. Wendel

The photoproduction of \eta'-mesons off different nuclei has been measured with the CBELSA/TAPS detector system for incident photon energies between 1500 - 2200 MeV. The transparency ratio has been deduced and compared to theoretical calculations describing the propagation of \eta'-mesons in nuclei. The comparison indicates a width of the \eta' -meson of the order of \Gamma= 15-25 MeV at \rho =\rho_0 for an average momentum p_{\eta'} = 1050 MeV/c, at which the \eta'-meson is produced in the nuclear rest frame. The inelastic \eta' N cross section is estimated to be 3 - 10 mb. Parameterizing the photoproduction cross section of \eta'-mesons by \sigma(A) = \sigma_0 A^{\alpha}, a value of \alpha = 0.84\pm0.03 has been deduced.

View original: http://arxiv.org/abs/1204.2914