Differential cross sections for [formula omitted] in the CM energy range from 2.0 to 3.1 GeV

• Published in: Physics letters. B Vol. 130; no. 6; pp. 449 - 453
• Main Authors: Althoff, M., Braunschweig, W., Gather, K., Kirschfink, F.J., Lübelsmeyer, K., Martyn, H.-U., Peise, G., Rimkus, J., Rosskamp, P., Sander, H.G., Schmitz, D., Siebke, H., Wallraff, W., Fischer, H.M., Hartmann, H., Hillen, W., Jocksch, A., Knop, G., Köpke, L., Kolanoski, H., Kück, H., Wedemeyer, R., Wermes, N., Wollstadt, M., Cooper, S., Eisenberg, Y., Hultschig, H., Joos, P., Koch, W., Kötz, U., Kowalski, H., Ladage, A., Lüke, D., Mättig, P., Mess, K.H., Notz, D., Pyrlik, J., Quarrie, D.R., Rushton, M., Schütte, W., Trines, D., Wolf, G., Xiao, Ch, Fohrmann, R., Hilger, E., Krasemann, H.L., Leu, P., Pandoulas, D., Poelz, G., Wiik, B.H., Al-Agil, I., Beuselinck, R., Binnie, D.M., Campbell, A.J., Dornan, P.J., Foster, B., Garbutt, D.A., Jones, T.D., Jones, W.G., McCardle, J., Sedgbeer, J.K., Bowler, M.G., Brock, I.C., Cashmore, R.J., Clarke, P.E.L., Devenish, R., Grossmann, P., Lloyd, S.L., Salmon, G.L., Thomas, J., Wyatt, T.R., Youngman, C., Hart, J.C., Harvey, J., Proudfoot, J., Saxon, D.H., Woodworth, P.L., Barreiro, F., Dittmar, M., Heyland, D., Holder, M., Neumann, B., Duchovni, E., Karshon, U., Mikenberg, G., Mir, R., Revel, D., Ronat, E., Shapira, A., Yekutieli, G., Barklow, T., Caldwell, A., Cherney, M., Izen, J.M., Mermikides, M., Rudolph, G., Strom, D., Venkataramania, H., Wicklund, E., Wu, Sau Lan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.1983
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/0370-2693(83)91541-1

Exclusive production of proton-antiproton pairs by two photon scattering at CM energies between 2.0 GeV and 3.1 GeV has been measured with the TASSO detector at the e +e − storage ring PETRA. The angular distribution is flat within the accepted CM angular range | cos Θ ∗|⩽0.7 . The integrated cross section (| cos Θ ∗|⩽0.6) drops from about 4 nb at 2 GeV to less than 0.5 nb above 3 GeV. For the two-photon production of the η c(2984) and its subsequent decay into proton-antiproton the upper limit Γ(η c →γγ)· B(η c → p p )<0.32 keV (95% CL) is found.