ε′/ε and rare K L decays from KTeV experiment
Journal
Nuclear Physics B - Proceedings Supplements
Journal Volume
96
Journal Issue
1-3
Pages
301-309
Date Issued
2001
Author(s)
Abstract
We update the current status for the measurement of the direct-CP violation parameters ε′/ε in the KTeV experiment at Fermilab. Substaintial statistics have been accumulated during the 1996-7 run and 1999 run for both ε′/ε and rare KL decay searches. The first KTeV result on ε′/ε published last year was Re(ε′/ε) = (28.0 ± 4.1) × 10-4 based on the 23% data from 1996-7 run. Combining with the previous E731, NA31 and the recent preliminary NA48 results, the grand average is Re(ε′/ε) = (19.3 ± 3.6) × 10-4 (with S = 1.49), more than 5σ above zero. More data from both KTeV and NA48 after completing the analysis will further improve the precision of this measurement in the near future and hopefully further improve the agreement. New results on the braching ratio and form factor measurements of KL → μ+μ-γ using 1997 data are also presented. We find that BR(KL → μ+μ-γ) = (3.66 ± 0.04stat ± 0.07syst) × 10-7. The form factor parameter αK* is measured to be αK* = -0.157+0.025-0.027. We make the first measurement of the parameter α from the D'Ambrosio, Isidori, and Portolés form factor, finding α = -1.53±0.09. This measurement of α limits the CKM parameter > -0.2. © 2001 Elsevier Science B.V. All rights reserved.
Type
journal article