APS » PROLA » Phys. Rev. Lett. » Volume 71 » Issue 24

Phys. Rev. Lett. 71, 3927 - 3930 (1993)

Axial and pseudoscalar nucleon form factors from low energy pion electroproduction
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Seonho Choi, M. A. Duval, L. Elouadrhiri, V. Estenne, G. Bardin, J. Berthot, P. Y. Bertin, N. De Botton, J. P. Didelez, H. Fonvieille, G. Fournier, R. Frascaria, M. Giffon, P. A. M. Guichon, C. Marchand, J. Marroncle, J. Martino, J. Miller, R. Nahabetian, B. Saghai, C. Samour, P. Vernin, and E. Warde
Service de Physique Nucléaire, DAPNIA, CE-Saclay F-9119 Gif-sur Yvette, France
Institut de Physique Nucléaire, Université Paris Sud, F91406 Orsay, France
Laboratoire de Physique Corpusculaire, Université Clermont II, F63170 Aubière, France
Institut de Physique Nucléaire, Université C. Bernard, F69622 Villeurbanne, France

Received 5 August 1993

The cross section for exclusive π+ electroproduction on the proton has been measured near threshold for the first time at two different values of the virtual photon polarization (ɛ∼0.2 and ɛ∼0.7). Using the low energy theorem for this reaction we deduce the axial and pseudoscalar weak form factors GA and GP at ‖t‖=0.073, 0.139, and 0.179 (GeV/c)2. The slope of GA agrees with the value obtained in neutrino experiments. GP satisfies the pion pole dominance hypothesis, which is thus verified for the first time in this range of transfer.


©1993 The American Physical Society

URL: http://link.aps.org/abstract/PRL/v71/p3927
DOI: 10.1103/PhysRevLett.71.3927
PACS: 13.60.Le, 11.40.Ha, 14.20.Dh

See Also

Comment: V. Bernard, N. Kaser, and Ulf-G. Meissner, Comment on ‘‘Axial and pseudoscalar nucleon form factors from low energy pion electroproduction’’, Phys. Rev. Lett. 72, 2810 (1994)

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