1. Test of chiral perturbation theory in η decays
- Author
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R. Bossingham, C. A. Meyer, J. Lüdemann, R. P. Haddock, A. Noble, A. Cooper, M. A. Faessler, A. H. Sanjari, T. Case, B. Schmid, H. Matthäy, G. Pinter, K. Braune, J. Zoll, C. Felix, B. M. Barnett, P. Schmidt, D. Walther, Eberhard Klempt, G. Folger, L. Montanet, W. Dünnweber, James A. Bistirlich, H. P. Dietz, Michael Kobel, Pàl Hidas, C.A. Baker, D. Umer, Claude Amsler, M. Suffert, I. Augustin, F. Walter, R. Hackmann, S. v. Dombrowski, D. S. Armstrong, P. Birien, Kenneth M. Crowe, M. Merkel, H. Kalinowski, Č. Zupančič, Z. Jávorfi, B. Kämmle, K. Beuchert, C. Kolo, F. Ould-Saada, C. Straßburger, D. Jamnik, P. Illinger, N. P. Hessey, D. Engelhardt, J. Brose, F. H. Heinsius, C. Völcker, U. Wiedner, Michael Doser, Mark J. Burchell, J. P. Merlo, M. Englert, Marcel Kunze, K. Königsmann, T. Kiel, J. Kisiel, H. Bossy, S. Ravndal, P. Blüm, D.V. Bugg, J. Salk, S. Waßmer, C.J. Batty, H. Koch, U. Strohbusch, R. Landua, E. Schäfer, and Krisztian Peters
- Subjects
Quantum chromodynamics ,Crystal ,Nuclear physics ,Physics ,Particle physics ,Chiral perturbation theory ,Pion ,Partial width ,Order (group theory) ,Charged particle - Abstract
The decay of the η-meson into three pions plays an important role as a test of low-energy QCD calculations in the framework of chiral perturbation theory. Previous experiments show results that are inconclusive or even contradictory. The Crystal Barrel experiment at LEAR has determined the braching ratiosΓ(η→3π0)/Γ(η→π+π−π0)=1.47±0.09±0.15 andΓ(η→γγ)/Γ(η→π+π−π0)=1.88±0.10±0.17 using its unique features to detect charged particles as well as neutral particles. The value for the first ratio agrees nicely with the theoretical predictions and solves previous experimental uncertainties. The second value, which yields a partial width ofΓ(η→π+π−π0)=(0.24±0.03) keV, shows that the same next-to-leading order chiral perturbation theory calculations still have some problems.
- Published
- 1994
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