کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1853433 | 1034228 | 2009 | 9 صفحه PDF | دانلود رایگان |

A sample of 7253 K±→π±e+e−(γ)K±→π±e+e−(γ) decay candidates with 1.0% background contamination has been collected by the NA48/2 experiment at the CERN SPS, which allowed a precise measurement of the decay properties. The branching ratio in the full kinematic range was measured to be BR=(3.11±0.12)×10−7BR=(3.11±0.12)×10−7, where the uncertainty includes also the model dependence. The shape of the form factor W(z)W(z), where z=(Mee/MK)2z=(Mee/MK)2, was parameterized according to several models, and, in particular, the slope δ of the linear form factor W(z)=W0(1+δz)W(z)=W0(1+δz) was determined to be δ=2.32±0.18δ=2.32±0.18. A possible CP violating asymmetry of K+K+ and K−K− decay widths was investigated, and a conservative upper limit of 2.1×10−22.1×10−2 at 90% CL was established.
Journal: Physics Letters B - Volume 677, Issue 5, 29 June 2009, Pages 246–254