Evidence for a πη-P-wave in [formula omitted]-annihilations at rest into π0π0η

• Published in: Physics letters. B 1999, Vol.446 (3), p.349-355
• Main Authors: Abele, A., Adomeit, J., Amsler, C., Baker, C.A., Barnett, B.M., Batty, C.J., Benayoun, M., Berdoz, A., Beuchert, K., Bischoff, S., Blüm, P., Braune, K., Case, T., Cramer, O., Credé, V., Crowe, K.M., Degener, T., Djaoshvili, N., Dombrowski, S.v., Doser, M., Dünnweber, W., Ehmanns, A., Engelhardt, D., Faessler, M.A., Giarritta, P., Haddock, R.P., Heinsius, F.H., Heinzelmann, M., Herbstrith, A., Herz, M., Hessey, N.P., Hidas, P., Holtzhaußen, C., Hüttmann, K., Jamnik, D., Kalinowsky, H., Kämmle, B., Kammel, P., Kisiel, J., Klempt, E., Koch, H., Kolo, C., Kunze, M., Kurilla, U., Lakata, M., Landua, R., Matthäy, H., McCrady, R., Meier, J., Meyer, C.A., Ouared, R., Ould-Saada, F., Peters, K., Pick, B., Pietra, C., Pinder, C.N., Ratajczak, M., Regenfus, C., Resag, S., Roethel, W., Schmidt, P., Seibert, R., Spanier, S., Stöck, H., Straßburger, C., Strohbusch, U., Suffert, M., Suh, J.S., Thoma, U., Tischhäuser, M., Uman, I., Völcker, C., Wallis-Plachner, S., Walther, D., Wiedner, U., Wittmack, K.
• Format: Article
• Language: English
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/S0370-2693(98)01544-5

A partial wave analysis is presented of two high-statistics data samples of protonium annihilation into π 0 π 0 η in liquid and 12 atm gaseous hydrogen. The contributions from the 1 S 0 , 3 P 1 and 3 P 2 initial atomic fine structure states to the two data sets are different. The change of their fractional contributions when going from liquid to gaseous H 2 as calculated in a cascade model is imposed in fitting the data. Thus the uncertainty in the fraction of S-state and P-state capture is minimized. Both data sets allow a description with a common set of resonances and resonance parameters. The inclusion of a π η P-wave in the fit gives supportive evidence for the ρ ̂ (1405) , with parameters compatible with previous findings.