A sample of more than one million K± → pi+pi−e±ν (Ke4) decay candidates with less than one percent background contamination has been collected by the NA48/2 experiment at the CERN SPS in 2003–2004, allowing a detailed study of the decay properties. The branching ratio, inclusive of Ke4 gamma decays, is measured to be BR(Ke4) = (4.257±0.016exp±0.031ext)× 10E−5 with a total relative error of 0.8%. This measurement complements the study of S and P-wave hadronic form factors by assigning absolute values to the relative hadronic form factors obtained earlier in a simultaneous analysis of the ππ scattering lengths conducted on the same data sample. The overall form factor normalization fs=5.705±0.017 (exp) ±0.031 (ext) is obtained with a total relative precision of 0.6%.
New measurement of the K± --> pi+pi−e± nu (Ke4) decayBranching Ratio and Hadronic Form Factors
ANZIVINO, Giuseppina;IMBERGAMO, ERMANNO;NAPPI, Aniello;PICCINI, Mauro;RAGGI, MAURO;VALDATA, Marisa
2012
Abstract
A sample of more than one million K± → pi+pi−e±ν (Ke4) decay candidates with less than one percent background contamination has been collected by the NA48/2 experiment at the CERN SPS in 2003–2004, allowing a detailed study of the decay properties. The branching ratio, inclusive of Ke4 gamma decays, is measured to be BR(Ke4) = (4.257±0.016exp±0.031ext)× 10E−5 with a total relative error of 0.8%. This measurement complements the study of S and P-wave hadronic form factors by assigning absolute values to the relative hadronic form factors obtained earlier in a simultaneous analysis of the ππ scattering lengths conducted on the same data sample. The overall form factor normalization fs=5.705±0.017 (exp) ±0.031 (ext) is obtained with a total relative precision of 0.6%.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
