Abstract
A monoenergetic positron (e +) beam (ΔT/T<5·10−4) from the Stuttgart pelletron accelerator and a 4.6 mg/cm2 Be target has been employed to investigatee + e −scattering in the MeV region in a large solid angle with high statistics by means of a novel positionsensitive detector system. Superimposed on the Bhabha scattering, a structure has been found at ane + kinetic energy of 2263 keV (810 keV excitation energy in thee + e −rest frame). From the energy-integrated resonance cross-section of\(\sigma _{res} \cdot \Gamma _{res}^{e^ + e^ - } \) ≅30 b·eV (c.m.) and the standard resonance cross-section we estimate partial resonance widths\(\Gamma _{res}^{e^ + e^ - } \) ≅72 meV or 24 meV for total angular momenta J=0 or J=1, respectively. The structure, which has not been predicted within the framework of quantum electrodynamics, coincides with one of the sum energies of the correlatede + e −lines observed in heavy-ion collisions.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Cowan, T., Backe, H., Bethge, K., Bokemeyer, H., Folger, H., Greenberg, J.S., Sakaguchi, K., Schwalm, D., Schweppe, J., Stiebing, K.E., Vincent, P.: Phys. Rev. Letters56, 444 (1986)
Cowan, T., Greenberg, J.S.: Proceedings of Physics of strong Fields. Greiner, W. (ed.), p. 111. New York: Plenum Press 1987
Erb, K.A., Lee, I.Y., Milner, W.T.: Phys. Lett. B181, 52 (1986)
Mills, A.P. Jr., Levy, J.: Phys. Rev. D36, 707 (1987)
Maier, K., Bauer, W., Briggmann, J., Carstanjen, H.-D., Decker, W., Diehl, J., Heinemann, V., Major, J., Schaefer, H.-E., Seeger, A., Stoll, H., Wesolowski, P., Widmann, E., Bosch, F., Koenig, W.: Z. Phys. A —Atomic Nuclei326, 527 (1987)
Wimmersperg, U. v., Connell, S.H., Hoernle, R.F.A., SiderasHaddad, E.: Phys. Rev. Letters59, 266 (1987)
Klinken, J. van et al.: (to be published)
Tsertos, H. et al.: (submitted to Phys. Lett. B)
Bauer, W., Maier, K., Major, J., Schaefer, H.-E., Seeger, A., Carstanjen, H.-D., Decker, W., Diehl, J., Stoll, H.: Appl. Phys. A43, 261 (1987)
Bhabha, H.J.: Proc. R. Soc., London A154, 195 (1936)
Segre, E.: Nuclei and particles. London: Benjamin 1977
Hansen, N.K., Pattison, P., Schneider, J.R.: Z. Phys. B — Con-densed Matter35, 215 (1979)
Chou, M.Y., Lam, P.K., Cohen, M.L., Loupias, G., Chomilier, J., Petiau, J.: Phys. Rev. Lett.49, 1452 (1982)
Reinhardt, J., Scherdin, A., Müller, B., Greiner, W.: Z. Phys. A — Atomic Nuclei327, 367 (1987)
Barut, A.O.: In: Quantum electrodynamics of strong fields. Greiner, W. (ed.), p. 755. New York: Plenum Press 1983
Wong, C.Y., Becker, R.L.: Phys. Letters B182, 251 (1986)
Author information
Authors and Affiliations
Additional information
Our thanks are due to the engineers and technicians at the accelerator M. Bechtel, E. Freiheit, W. Funk, R. Klumpp, R. Prokopez, L. Raschke, and G. Steudle. The assistance of R. Henes, P. Keppler, G. Wiederoder, T. Grund, and M. Schäfer is gratefully acknowledged. The authors also acknowledge the construction of electronic control units by J. Hoffmann, H.P. Liebold, and M. Richter of GSI Darmstadt and the preparation of the Be targets by Dr. S. Stiltz of the Pulvermetallurgisches Laboratorium at the MPI für Metallforschung. Last not least we want to thank the Deutsche Forschungsgemeinschaft and the Bundesministerium für Forschung und Technologie, Bonn, for financial support as well as the Gewerbeaufsichtsamt Stuttgart for their excellent collaboration.
Rights and permissions
About this article
Cite this article
Maier, K., Widmann, E., Bauer, W. et al. Evidence for a resonance in positron-electron scattering at 810 keV centre-of-mass Energy. Z. Physik A - Atomic Nuclei 330, 173–181 (1988). https://doi.org/10.1007/BF01293393
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01293393