2005/03/31 by I. Giller, A. Ocherashvili, T. Ebertshäuser +3
Physics and Astronomy · #Black Holes and Theoretical Physics #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ex #hep-ph #nucl-th
paper · pdf · doi:10.1140/epja/i2005-10116-1
published as Eur.Phys.J. A25 (2005) 229-240 · 23 pages, 14 figures, discussion of the ChPT calculation extended
arxiv created 2005/06/06 · openalex publication_date 2005/08/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We discuss the reaction π- e- → π- e- π0 with the purpose of obtaining information on the γπ→ ππ anomalous amplitude \cal F3π. We compare a full calculation at \cal O(p6) in chiral perturbation theory and various phenomenological predictions with the existing data of Amendolia \em et al. By integrating our theory results using Monte Carlo techniques we obtain σ= 2.05 nb at \cal O(p6) and σ= 2.17 nb after including the dominant electromagnetic correction. Both results are in good agreement with the experimental cross section of σ= (2.11 ± 0.47) nb. On the basis of the ChPT results one would extract from the the experimental cross section as amplitudes \cal F3π(0)\rm extr = (9.9 ± 1.1) GeV-3 and \cal F3π(0)\rm extr = (9.6 ± 1.1) GeV-3, respectively, which have to be compared with the low-energy theorem \cal F3π=e/(4π2 Fπ3)=9.72 GeV-3. We emphasize the need for new data to allow for a comparison of experimental and theoretical distributions and to obtain \cal F3π with smaller uncertainty.