The semileptonic decay of the neutral K meson, KL0→π± e∓ν (Ke3), was used to study the strangeness-changing weak interaction of hadrons. A sample of 5.6 million reconstructed events recorded by the NA48 experiment was used to measure the Dalitz plot density. Admitting all possible Lorentz-covariant couplings, the form factors for vector (f+(q2)), scalar (fS) and tensor (fT) interactions were measured. The linear slope of the vector form factor λ+=0.0284±0.0007±0.0013 and values for the ratios |fS/f+(0)|=0.015-0.010+0.007±0.012 and |fT/f+(0)|=0.05-0.04+0. 03±0.03 were obtained. The values for fS and fT are consistent with zero. Assuming only vector-axial-vector couplings, λ+=0.0288±0. 0004±0.0011 and a good fit consistent with pure V-A couplings were obtained. Alternatively, a fit to a dipole form factor yields a pole mass of M=859±18 MeV, consistent with the K*(892) mass.
Measurement of K0(e3) form-factors.
ANZIVINO, Giuseppina;IMBERGAMO, ERMANNO;NAPPI, Aniello;PICCINI, Mauro
2004
Abstract
The semileptonic decay of the neutral K meson, KL0→π± e∓ν (Ke3), was used to study the strangeness-changing weak interaction of hadrons. A sample of 5.6 million reconstructed events recorded by the NA48 experiment was used to measure the Dalitz plot density. Admitting all possible Lorentz-covariant couplings, the form factors for vector (f+(q2)), scalar (fS) and tensor (fT) interactions were measured. The linear slope of the vector form factor λ+=0.0284±0.0007±0.0013 and values for the ratios |fS/f+(0)|=0.015-0.010+0.007±0.012 and |fT/f+(0)|=0.05-0.04+0. 03±0.03 were obtained. The values for fS and fT are consistent with zero. Assuming only vector-axial-vector couplings, λ+=0.0288±0. 0004±0.0011 and a good fit consistent with pure V-A couplings were obtained. Alternatively, a fit to a dipole form factor yields a pole mass of M=859±18 MeV, consistent with the K*(892) mass.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
