This Letter reports on a new high precision measurement of the form factors of the KL -> pi mu nu decay. The data sample of about 2.3 × 10^6 events was recorded in 1999 by the NA48 experiment at CERN. Studying the Dalitz plot density we measured a linear, $\lambda^{'}_{+} = (20.5 ± 2.2stat ±2.4syst ) × 10-3 , and a quadratic, $\lambda^{''}_{+} = (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 $\lambda_{0}= (9.5 ± 1.1stat ± 0.8syst ) × 10-3 . Using a linear fit our results were: $\lambda_{+} = (26.7 ± 0.6stat ± 0.8syst ) × 10-3 and $\lambda_{0} = (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
VELTRI, MICHELE;
2007
Abstract
This Letter reports on a new high precision measurement of the form factors of the KL -> pi mu nu decay. The data sample of about 2.3 × 10^6 events was recorded in 1999 by the NA48 experiment at CERN. Studying the Dalitz plot density we measured a linear, $\lambda^{'}_{+} = (20.5 ± 2.2stat ±2.4syst ) × 10-3 , and a quadratic, $\lambda^{''}_{+} = (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 $\lambda_{0}= (9.5 ± 1.1stat ± 0.8syst ) × 10-3 . Using a linear fit our results were: $\lambda_{+} = (26.7 ± 0.6stat ± 0.8syst ) × 10-3 and $\lambda_{0} = (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.
