Pismo uredniku
The axial form factor of the nucleon from electro-pion production at low q2
M. Potokar (A1 collaboration at MAMI)
; Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
Sažetak
Results of the measurement of the transverse and longitudinal cross-section for coincident electro-production of positively charged pions on protons measured in parallel kinematics at the invariant mass of W = 1125 MeV and at three fourmomentum transfers q 2 = −0.117, −0.195 and −0.273 GeV2 are presented. An axial-mass parameter of high accuracy was extracted from a preliminary analysis of the transverse cross-section within the Mainz effective Lagrangian model of the nucleon. The value supports the prediction of the chiral perturbation theory that pion-loop corrections effectively increase the value of the axial mass extracted from pion electro-production data relative to that from neutrino scattering.
Ključne riječi
axial dipole mass; axial form factor; pion electro-production
Hrčak ID:
305288
URI
Datum izdavanja:
1.3.1999.
Posjeta: 115 *