Momentum dependence of the imaginary part of the - and -nucleus optical potential

• Published in: The European physical journal. A, Hadrons and nuclei Hadrons and nuclei, 2016-09, Vol.52 (9), p.1-10
• Main Authors: Friedrich, S., Nanova, M., Metag, V., Afzal, F. N., Bayadilov, D., Bantes, B., Beck, R., Becker, M., Böse, S., Brinkmann, K. -T., Crede, V., Drexler, P., Eberhardt, H., Elsner, D., Frommberger, F., Funke, Ch, Gottschall, M., Grüner, M., Gutz, E., Hammann, Ch, Hannappel, J., Hartmann, J., Hillert, W., Hoffmeister, Ph, Honisch, Ch, Jude, T., Kaiser, D., Kalischewski, F., Keshelashvili, I., Klein, F., Koop, K., Krusche, B., Lang, M., Makonyi, K., Messi, F., Müller, J., Müllers, J., Piontek, D. -M., Rostomyan, T., Schaab, D., Schmidt, Ch, Schmieden, H., Schmitz, R., Seifen, T., Sokhoyan, V., Sowa, C., Spieker, K., Thiel, A., Thoma, U., Triffterer, T., Urban, M., van Pee, H., Walther, D., Wendel, Ch, Werthmüller, D., Wiedner, U., Wilson, A., Witthauer, L., Wunderlich, Y., Zaunick, H. -G.
• Format: Article
• Language: English
• Subjects: Hadrons; Heavy Ions; Nuclear cross sections; Nuclear Fusion; Nuclear Physics; Particle and Nuclear Physics; Physics; Physics and Astronomy; Regular Article - Experimental Physics
• ISSN: 1434-6001; 1434-601X
• DOI: 10.1140/epja/i2016-16297-4

. The photoproduction of and mesons off carbon and niobium nuclei has been measured as a function of the meson momentum for incident photon energies of 1.2-2.9GeV at the electron accelerator ELSA. The mesons have been identified via the and decays, respectively, registered with the CBELSA/TAPS detector system. From the measured meson momentum distributions the momentum dependence of the transparency ratio has been determined for both mesons. Within a Glauber analysis the in-medium and widths and the corresponding absorption cross sections have been deduced as a function of the meson momentum. The results are compared to recent theoretical predictions for the in-medium width and -N absorption cross sections. The energy dependence of the imaginary part of the - and -nucleus optical potential has been extracted. The finer binning of the present data compared to the existing data allows a more reliable extrapolation towards the production threshold. The modulus of the imaginary part of the -nucleus potential is found to be about three times smaller than recently determined values of the real part of the -nucleus potential, which makes the meson a suitable candidate for the search for meson-nucleus bound states. For the meson, the modulus of the imaginary part near threshold is comparable to the modulus of the real part of the potential. As a consequence, only broad structures can be expected, which makes the observation of mesic states very difficult experimentally.