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Abstract
A sample of 3120 K±→π±μ+μ−K±→π±μ+μ− decay candidates with (3.3±0.7)%(3.3±0.7)% background contamination has been collected by the NA48/2 experiment at the CERN SPS, allowing a detailed study of the decay properties. The branching ratio was measured to be BR=(9.62±0.25)×10−8BR=(9.62±0.25)×10−8. The form factor W(z)W(z), where z=2(Mμμ/MK)z=(Mμμ/MK)2, was parameterized according to several models. In particular, the slope of the linear form factor W(z)=W0(1+δz)W(z)=W0(1+δz) was measured to be δ=3.11±0.57δ=3.11±0.57. Upper limits of 2.9×10−22.9×10−2 and 2.3×10−22.3×10−2 on possible charge asymmetry and forward–backward asymmetry were established at 90% CL. An upper limit BR(K±→π∓μ±μ±)<1.1×10−9BR(K±→π∓μ±μ±)<1.1×10−9 was established at 90% CL for the rate of the lepton number violating decay.
Original language | English |
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Pages (from-to) | 107-115 |
Number of pages | 9 |
Journal | Physics Letters B |
Volume | B697 |
Issue number | 2 |
Early online date | 26 Jan 2011 |
DOIs | |
Publication status | Published - 28 Feb 2011 |
Keywords
- Rare kaon decay
- ΔS=1ΔS=1 weak NC decay
- Lepton number violation
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Dive into the research topics of 'New measurement of the K+- --> pi+-mu+mu- decay'. Together they form a unique fingerprint.Projects
- 1 Finished
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Responsive RA submission for a "New measurement of the ratio Gamma(K->e nu)/Gamma(K->mu nu) at NA48/2"
Lazzeroni, C. (Principal Investigator) & Watkins, P. (Co-Investigator)
SCIENCE & TECHNOLOGY FACILITIES COUNCIL
1/04/08 → 31/03/11
Project: Research Councils