his Letter reports on a new high precision measurement of the form factors of the KL → π± μ∓ νμ decay. The data sample of about 2.3 × 106 events was recorded in 1999 by the NA48 experiment at CERN. Studying the Dalitz plot density we measured a linear, λ+ ′ = (20.5 ± 2.2stat ± 2.4syst) × 10-3, and a quadratic, λ+ ″ = (2.6 ± 0.9stat ± 1.0syst) × 10-3 term in the power expansion of the vector form factor. No evidence was found for a second order term for the scalar form factor; the linear slope was determined to be λ0 = (9.5 ± 1.1stat ± 0.8syst) × 10-3. Using a linear fit our results were: λ+ = (26.7 ± 0.6stat ± 0.8syst) × 10-3 and λ0 = (11.7 ± 0.7stat ± 1.0syst) × 10-3. A pole fit of the form factors yields: mV = (905 ± 9stat ± 17syst) MeV / c2 and mS = (1400 ± 46stat ± 53syst) MeV / c2.
Measurement of K0(mu3) form factors
ANZIVINO, Giuseppina;IMBERGAMO, ERMANNO;NAPPI, Aniello;PICCINI, Mauro
2007
Abstract
his Letter reports on a new high precision measurement of the form factors of the KL → π± μ∓ νμ decay. The data sample of about 2.3 × 106 events was recorded in 1999 by the NA48 experiment at CERN. Studying the Dalitz plot density we measured a linear, λ+ ′ = (20.5 ± 2.2stat ± 2.4syst) × 10-3, and a quadratic, λ+ ″ = (2.6 ± 0.9stat ± 1.0syst) × 10-3 term in the power expansion of the vector form factor. No evidence was found for a second order term for the scalar form factor; the linear slope was determined to be λ0 = (9.5 ± 1.1stat ± 0.8syst) × 10-3. Using a linear fit our results were: λ+ = (26.7 ± 0.6stat ± 0.8syst) × 10-3 and λ0 = (11.7 ± 0.7stat ± 1.0syst) × 10-3. A pole fit of the form factors yields: mV = (905 ± 9stat ± 17syst) MeV / c2 and mS = (1400 ± 46stat ± 53syst) MeV / c2.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
