A sample of more than one million K-+/- -> pi(+)pi(-)e(+/-)v (K-e4) 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 K-e4 gamma decays, is measured to be BR(K-e4) = (4.257 +/- 0.016(exp) +/- 0.031(ext)) x 10(-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 pi pi scattering lengths conducted on the same data sample. The overall form factor normalization f(s) = 5.705 +/- 0.017(exp) +/- 0.031(ext) is obtained with a total relative precision of 0.6%. (c) 2012 Elsevier B.V. All rights reserved.

New measurement of the K-+/- -> pi(+)pi(-)e(+/-)v (Ke4) decay branching ratio and hadronic form factors

COLLAZUOL, GIANMARIA;
2012

Abstract

A sample of more than one million K-+/- -> pi(+)pi(-)e(+/-)v (K-e4) 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 K-e4 gamma decays, is measured to be BR(K-e4) = (4.257 +/- 0.016(exp) +/- 0.031(ext)) x 10(-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 pi pi scattering lengths conducted on the same data sample. The overall form factor normalization f(s) = 5.705 +/- 0.017(exp) +/- 0.031(ext) is obtained with a total relative precision of 0.6%. (c) 2012 Elsevier B.V. All rights reserved.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2527609
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